使用javaweb进行用户管理系统的增删改查，分页和条件查询

你的名字 2024-04-17 05:53 58阅读 0赞

## **使用javaweb进行用户管理系统的增删改查，分页和条件查询** ##

如有转载请标注来源！！！谢谢配合  
源码已经上传，可以自行下载  
[https://download.csdn.net/download/weixin\_44476520/13087005][https_download.csdn.net_download_weixin_44476520_13087005]  
主要实现增删改查，分为customer表和user表，customer表主要是客户实现增删改查，分页，和条件查询，user表主要是实现用户的登陆和注册功能  
**dao层的接口：**

（customerDao）dao层接口的代码：
    package cn.cyp.dao;
    
    import cn.cyp.bean.Customer;
    import cn.cyp.bean.pageBean;
    
    import java.util.List;
    import java.util.Map;
    
    /**
     * @Author:cyp
     * @date:2019/8/14 19:54
     * @Desc:
     */
    public interface customerDao {
        //查询所有用户
        List<Customer> selectAllCustomer();
        //进行添加判断邮箱
        Customer ckEmailName(String email);
        //增加用户
        Boolean addCustomer(Customer customer);
        // 删除用户
        void deleteCustomer(int id);
        //修改
        //修改数据
        Customer updateCustomer(int id);
        //编辑数据
        Boolean editeCustomer(Customer customer);
        //显示查询的总共有多少条
        int findTotalCounts(Map<String, String[]> map);
        //查询每页显示的数据是什么
        List<Customer> findTotalCustomers(pageBean pageBean, Map<String, String[]> map);
    
    }

（userDao）dao层接口：
    package cn.cyp.dao;
    
    import cn.cyp.bean.User;
    
    /**
     * @Author:cyp
     * @date:2019/8/16 8:20
     * @Desc:
     */
    public interface userDao {
    
        User userLogin(User user);
        Boolean registerUser(User user);
        User registerOk(String username);
    }

**dao层接口的实现：**

（customerDaoImpl）dao层接口实现的代码：
    package cn.cyp.dao.impl;
    
    import cn.cyp.bean.Customer;
    import cn.cyp.bean.pageBean;
    import cn.cyp.dao.customerDao;
    import cn.cyp.util.jdbcUtil;
    import org.springframework.dao.DataAccessException;
    import org.springframework.jdbc.core.BeanPropertyRowMapper;
    import org.springframework.jdbc.core.JdbcTemplate;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    import java.util.Set;
    
    /**
     * @Author:cyp
     * @date:2019/8/14 19:55
     * @Desc:dao层，发送sql语句到db中
     */
    public class customerDaoImpl implements customerDao {
        //jdbc模板操作
        JdbcTemplate template = new JdbcTemplate(jdbcUtil.getDataSource());
    
        //查询所有人的信息
        @Override
        public List<Customer> selectAllCustomer() {
            String sql = "select  * from customer";
            List<Customer> list = template.query(sql, new BeanPropertyRowMapper<Customer>(Customer.class));
            return list;
        }
    
        //检查邮箱
        @Override
        public Customer ckEmailName(String email) {
            String sql = "select * from customer where email=?";
            try {
                return this.template.queryForObject(sql, new BeanPropertyRowMapper<Customer>(Customer.class), email);
            } catch (DataAccessException e) {
                e.printStackTrace();
            }
            return null;
        }
    
        //添加客户的信息
        @Override
        public Boolean addCustomer(Customer customer) {
            //定义sql语句
            String sql = "insert into customer(name,sex,age,addr,qq,email) values(?,?,?,?,?,?) ";
            //执行sql
            int add = template.update(sql, customer.getName(), customer.getSex(),
                    customer.getAge(), customer.getAddr(), customer.getQq(), customer.getEmail());
            if (add > 0) {
                return true;
            }
            return false;
        }
    
        //删除用户信息
        @Override
        public void deleteCustomer(int id) {
            String sql = "delete from customer where id=?";
            template.update(sql, id);
        }
    
        //查询数据库是否有需要修改的数据
        @Override
        public Customer updateCustomer(int id) {
            String sql = "select * from customer where id=id";
            List<Customer> customers = template.query(sql, new BeanPropertyRowMapper<Customer>(Customer.class));
            for (Customer customer1 : customers) {
                if (customer1.getId() == id) {
                    return customer1;
                }
            }
            return null;
        }
    
        @Override
        public Boolean editeCustomer(Customer customer) {
            String sql = "update customer set name=?,sex=?,age=?,addr=?,qq=?,email=? where id=?";
            int edit = template.update(sql, customer.getName(), customer.getSex(),
                    customer.getAge(), customer.getAddr(), customer.getQq(), customer.getEmail(), customer.getId());
            if (edit > 0) {
                return true;
            }
            return false;
        }
    
        /**
         *    分页功能的实现，查询总共有多少条数
         */
        @Override
        public int findTotalCounts(Map<String, String[]> map) {
            // String sql = "select count(1) from customer";
            // try {
            //     return template.queryForObject(sql, Integer.class);
            // } catch (Exception e) {
            //     e.printStackTrace();
            //     throw new RuntimeException("sql查询条数语句出现异常");
            // }
            StringBuilder sql =new StringBuilder("select count(1) from customer where 1=1");
            //设置可变参数
            List<Object> list=new ArrayList<>();
            Set<String> keySet = map.keySet();
            for (String key:keySet){
                //排除pageNum
                if ("pageNum".equals(key)){
                    //跳出本次循环
                    continue;
                }
                String value=map.get(key)[0];
                if (value!=null&&!value.equals("")){
                    sql.append(" and " +  key + " like ?");
                    list.add("%" +value+ "%");
                }
            }
            return template.queryForObject(sql.toString(), Integer.class,list.toArray());
        }
    
        //查询每页显示的数目
        @Override
        public List<Customer> findTotalCustomers(pageBean pageBean, Map<String, String[]> map) {
            StringBuilder sql =new StringBuilder("select * from customer where 1=1");
            //将参数放在list集合中
            List<Object> list = new ArrayList<>();
            //将map1集合中的内容循环遍历进行判断
            Set<String> key = map.keySet();
            for(String key1:key){
                //排除pageNum
                if ("pageNum".equals(key1)){
                    //跳出本次循环
                    continue;
                }
                String value = map.get(key1)[0];
                if (key1!= null && !key1.equals("")){
                    sql.append(" and " +  key1 + " like ?");
                    list.add("%" +value+ "%");
                }
            }
            //进行拼接分页
            sql.append(" limit ?,?");
            list.add(pageBean.getStartIndex());
            list.add(pageBean.getPageSize());
            try {
                 //list.toArray转化成
                 return this.template.query(sql.toString(), new BeanPropertyRowMapper<Customer>(Customer.class), list.toArray());
            } catch (DataAccessException e) {
                e.printStackTrace();
                throw new RuntimeException("sql查询分页出现异常");
            }
        }
    }

（userDaoImpl）dao层接口实现的代码：
    package cn.cyp.dao.impl;
    
    import cn.cyp.bean.User;
    import cn.cyp.dao.userDao;
    import cn.cyp.util.jdbcUtil;
    import org.springframework.dao.DataAccessException;
    import org.springframework.jdbc.core.BeanPropertyRowMapper;
    import org.springframework.jdbc.core.JdbcTemplate;
    
    import java.util.Date;
    
    /**
     * @Author:cyp
     * @date:2019/8/16 8:19
     * @Desc:
     */
    public class userDaoImpl implements userDao {
        //jdbc模板操作
        JdbcTemplate template = new JdbcTemplate(jdbcUtil.getDataSource());
    
        //查询登陆的用户是否是数据库中的
        @Override
        public User userLogin(User user) {
            String sql = "select * from user where username=? and pwd=?";
            try {
                return template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), user.getUsername(), user.getPwd());
            } catch (DataAccessException e) {
                e.printStackTrace();
            }
    
            //使用list进行获取
            // String username = user.getUsername();
            // String pwd = user.getPwd();
            //
            // String sql="select * from admin ";
            // List<User> list = template.query(sql, new BeanPropertyRowMapper<User>(User.class));
            // for(User user1:list){
            //     if(user1.getUsername().equals(username.trim()) &  user1.getPwd().equals(pwd.trim())){
            //         return user;
            //     }
            // }
            return null;
        }
    
        //添加用户，进行判断该用户是否已经存在，使名字唯一
        @Override
        public User registerOk(String username) {
            String sql = "select * from user where username=?";
            try {
                return this.template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username);
            } catch (DataAccessException e) {
                e.printStackTrace();
            }
            return null;
        }
        @Override
        public Boolean registerUser(User user) {
            Date date=new Date();
            String sql="insert into user(username,pwd,nickname,createtime,updatetime) values(?,?,?,?,?)";
            int update = template.update(sql, user.getUsername(), user.getPwd(),user.getNickname(),date,date);
            if (update>0){
                return true;
            }
            return null;
        }
    }

**service层的接口：**

（customerService）service层接口的代码：
    package cn.cyp.service;
    
    import cn.cyp.bean.Customer;
    import cn.cyp.bean.pageBean;
    
    import java.util.List;
    import java.util.Map;
    
    /**
     * @Author:cyp
     * @date:2019/8/14 19:12
     * @Desc:
     */
    public interface customerService {
        //查询所有用户
        List<Customer> selectAllCustomer();
       // 增加用户
        Boolean addCustomer(Customer customer);
       // 删除用户
       void deleteCustomer(int id);
        //删除选中的用户
        void deleteCheckedCustomer(String[] items);
        //修改用户
        //判断用户id是不是选择的id
        Customer updateCustomer(int id);
        //进行编辑用户的信息
        boolean editCustomer(Customer customer);
    
        //关于分页的方法
        pageBean findCustomerPage(pageBean pageBean, Map<String, String[]> map);
    }

（userService）service层接口的代码：
    package cn.cyp.service;
    
    import cn.cyp.bean.User;
    
    /**
     * @Author:cyp
     * @date:2019/8/15 22:05
     * @Desc:
     */
    public interface userService {
        User userLogin(User user);
        Boolean registerUser(User user);
    }

**service层的接口的实现：**

（userServiceImpl）service层接口实现的代码：
    package cn.cyp.service.impl;
    import cn.cyp.bean.User;
    import cn.cyp.dao.userDao;
    import cn.cyp.dao.impl.userDaoImpl;
    import cn.cyp.service.userService;
    import cn.cyp.util.MD5Utils;
    
    /**
     * @Author:cyp
     * @date:2019/8/15 22:05
     * @Desc:
     */
    public class userServiceImpl implements userService {
        @Override
        public User userLogin(User user){
            //创建dao对象，调用dao里面的方法，进行判断
            userDao userDao =new userDaoImpl();
            return  userDao.userLogin(user);
        }
        //判断用户是否存在
        @Override
        public Boolean registerUser(User user) {
            //进行md5加密
            user.setPwd(MD5Utils.getPWD(user.getPwd()));
            //创建dao对象，调用dao里面的方法，进行判断
            userDao userDao =new userDaoImpl();
            //判断用户名是否为空
            User u=userDao.registerOk(user.getUsername());
            if (u==null){
                userDao.registerUser(user);
                return true;
            }
            return  false;
        }
    }

（addCustomerServlet）添加客户功能的实现，web层的代码：
    package cn.cyp.web;
    
    import cn.cyp.bean.Customer;
    import cn.cyp.service.customerService;
    import cn.cyp.service.impl.customerServiceImpl;
    import org.apache.commons.beanutils.BeanUtils;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.lang.reflect.InvocationTargetException;
    import java.util.Map;
    
    /**
     * @Author:cyp
     * @date:2019/8/16 20:38
     * @Desc:添加用户信息的页面
     */
    @WebServlet(urlPatterns = "/addCustomerServlet")
    public class addCustomerServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //通过map获取页面上输入框的所有内容
            response.setContentType("text/html;charset=utf-8");
            //设置post请求字符集
            request.setCharacterEncoding("utf-8");
            Map<String, String[]> map = request.getParameterMap();
            Customer customer = new Customer();
            //进行封装实体类
            try {
                BeanUtils.populate(customer, map);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            }
            customerService addCustomerService = new customerServiceImpl();
            Boolean customer1 = addCustomerService.addCustomer(customer);
            if (customer1 == true) {
                response.getWriter().print("添加成功");
                request.getRequestDispatcher("/pageBeanServlet").forward(request, response);
            } else {
                response.getWriter().print("添加失败");
               request.setAttribute("msg","邮箱已存在");
                //    当邮箱存在的时候，进行回显到添加界面
                request.setAttribute("old", customer);
                request.getRequestDispatcher("addCustomer.jsp").forward(request, response);
            }
        }
    }

**servlet**

（deleteCustomerServlet）删除客户功能的实现，web层的代码：
    package cn.cyp.web;
    
    import cn.cyp.service.customerService;
    import cn.cyp.service.impl.customerServiceImpl;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /**
     * @Author:cyp
     * @date:2019/8/17 14:47
     * @Desc:
     */
    @WebServlet(urlPatterns = "/deleteCustomerServlet")
    public class deleteCustomerServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        }
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //获取前台传来的id值
            String idstr = request.getParameter("id");
            int id=Integer.parseInt(idstr);
    
            customerService deleteCustomerService = new customerServiceImpl();
            deleteCustomerService.deleteCustomer(id);
            //删除成功
            response.sendRedirect(request.getContextPath()+"/pageBeanServlet");
                // request.getRequestDispatcher("/selectCustomerServlet").forward(request,response);
                System.out.println("删除成功");
    
            }
        }

（deleteCheckedCustomerServlet）删除选中客户功能的实现，web层的代码：
    package cn.cyp.web;
    
    import cn.cyp.service.customerService;
    import cn.cyp.service.impl.customerServiceImpl;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /**
     * @Author:cyp
     * @date:2019/8/20 18:08
     * @Desc:
     */
    @WebServlet(urlPatterns = "/deleteCheckedCustomerServlet")
    public class deleteCheckedCustomerServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            String[] items = request.getParameterValues("items");
            customerService deleteCustomerService = new customerServiceImpl();
            deleteCustomerService.deleteCheckedCustomer(items);
            response.sendRedirect(request.getContextPath()+"/pageBeanServlet");
        }
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        }
    }

（pageBeanServlet）分页和条件查询功能的实现	，web层的代码：
    package cn.cyp.web;
    import cn.cyp.bean.pageBean;
    import cn.cyp.service.customerService;
    import cn.cyp.service.impl.customerServiceImpl;
    import org.apache.commons.beanutils.BeanUtils;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.lang.reflect.InvocationTargetException;
    import java.util.Map;
    
    /**
     * @Author:cyp
     * @date:2019/8/22 9:34
     * @Desc:
     */
    @WebServlet(urlPatterns = "/pageBeanServlet")
    public class pageBeanServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
             //解决乱码问题
            request.setCharacterEncoding("utf-8");
            response.setContentType("text/html;  charset=utf-8");
            //条件查询，获取前台传过来的pageNum，name，sex,age
            Map<String, String[]> map=request.getParameterMap();
            //实例化一个pageBean变量
            pageBean pageBean=new pageBean();
            //    使用BeanUtil封装实体类
            try {
                BeanUtils.populate(pageBean,map);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            }
    
            //    注入业务层
            customerService customerService=new customerServiceImpl();
            pageBean pageBean1=customerService.findCustomerPage(pageBean,map);
            //将pageBean的值传到浏览器
            request.setAttribute("pageBean",pageBean1);
            //实现输入框的值回显的功能
            request.setAttribute("map",map);
            request.getRequestDispatcher("/list.jsp").forward(request,response);
    
        }
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
            doPost(request,response);
        }
    }

（selectCustomerServlet）查询所有用户功能的实现	，web层的代码：
    package cn.cyp.web;
    
    import cn.cyp.bean.Customer;
    import cn.cyp.service.customerService;
    import cn.cyp.service.impl.customerServiceImpl;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.util.List;
    
    /**
     * @Author:cyp
     * @date:2019/8/14 19:17
     * @Desc:
     */
    @WebServlet(urlPatterns= "/selectCustomerServlet")
    public class selectCustomerServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         doGet(request,response);
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          customerService selectCustomerService =new customerServiceImpl();
            //使用list集合来接收从service传过来的值
            List<Customer> list= selectCustomerService.selectAllCustomer();
    
          request.setAttribute("list",list);
          request.getRequestDispatcher("/list.jsp").forward(request,response);
        }
    }

（updateCustomerServlet）修改用户功能的实现	，web层的代码：
    package cn.cyp.web;
    
    import cn.cyp.bean.Customer;
    import cn.cyp.service.customerService;
    import cn.cyp.service.impl.customerServiceImpl;
    import org.apache.commons.beanutils.BeanUtils;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.lang.reflect.InvocationTargetException;
    import java.util.Map;
    
    /**
     * @Author:cyp
     * @date:2019/8/16 19:45
     * @Desc:修改操作
     */
    @WebServlet(urlPatterns= "/updateCustomerServlet")
    public class updateCustomerServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //通过map获取页面上输入框的所有内容
            response.setContentType("text/html;charset=utf-8");
            //设置post请求字符集
            request.setCharacterEncoding("utf-8");
    
            Map<String, String[]> map = request.getParameterMap();
            Customer customer = new Customer();
            //进行封装实体类
            try {
                BeanUtils.populate(customer, map);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            }
            customerService updateCustomerService = new customerServiceImpl();
            boolean customer1 = updateCustomerService.editCustomer(customer);
            if (customer1 == true) {
                response.getWriter().print("添加成功");
                request.getRequestDispatcher("/pageBeanServlet").forward(request, response);
            } else {
                response.getWriter().print("添加失败");
            }
        }
    
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            response.setContentType("text/html;charset=utf-8");
            String idstr = request.getParameter("id");
            int id=Integer.parseInt(idstr);
    
            customerService updateCustomerService = new customerServiceImpl();
            Customer customer1 = updateCustomerService.updateCustomer(id);
            //判断是否是需要的id
            if (customer1!=null) {
                request.setAttribute("customer",customer1);
                request.getRequestDispatcher("/updateCustomer.jsp").forward(request,response);
            }
            System.out.println("查询不到");
        }
    
    }

（userLoginServlet）user登陆功能的实现
    package cn.cyp.web;
    
    import cn.cyp.bean.User;
    import cn.cyp.service.impl.userServiceImpl;
    import cn.cyp.service.userService;
    import cn.cyp.util.MD5Utils;
    import org.apache.commons.beanutils.BeanUtils;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.*;
    import java.io.IOException;
    import java.lang.reflect.InvocationTargetException;
    import java.util.Map;
    
    /**
     * @Author:cyp
     * @date:2019/8/15 21:06
     * @Desc: 查询所有的人员的信息的dao层
     */
    @WebServlet(urlPatterns = "/userLoginTestServlet")
    public class userLoginServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
            response.setContentType("text/html;charset=utf-8");
            //获取用户输入的验证码
            String img = request.getParameter("img");
            //获取服务器验证码的内容，session
            HttpSession session = request.getSession();
    
            //获取登陆框的内容
            String imgsession =(String) session.getAttribute("CHECKCODE_SERVER");
            //判断不匹配的情况
            
            if(!img.equalsIgnoreCase(imgsession)){
                request.setAttribute("imgmsg","验证码错误");
                request.getRequestDispatcher("/login.jsp").forward(request,response);
                return;
            }
            //再进行获取从前台输入的内容
            Map<String, String[]> map = request.getParameterMap();
            User user =new User();
            //将从登陆框中获取的内容通过传参传到后面，进行判断
            try {
                //进行MD5解码
                user.setUsername(MD5Utils.getPWD(user.getPwd()));
                BeanUtils.populate(user,map);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            }
            userService userLoginService =new userServiceImpl();
            User adminService1 = userLoginService.userLogin(user);
            if(adminService1!=null){
                //表示成功之后将用户名记住
                // Cookie cookie=new Cookie("name",username);
                // //设置生存时间
                // cookie.setMaxAge(60*60);
                // //响应给浏览器
                // response.addCookie(cookie);
                response.sendRedirect(request.getContextPath()+"/pageBeanServlet");
                //创建ssession对象
                HttpSession session1 = request.getSession();
                session1.setAttribute("username",user.getUsername());
                response.getWriter().print("登陆成功");
            }else{
               request.getRequestDispatcher("/login.jsp").forward(request,response);
                response.getWriter().print("登录失败");
    
            }
    
        }
    }

（userOutLoginServlet）user注销功能的的实现，web层的代码：
    package cn.cyp.web;
    
    import javax.servlet.ServletException;
    import javax.servlet.SessionCookieConfig;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import java.io.IOException;
    
    /**
     * @Author:cyp
     * @date:2019/8/16 15:17
     * @Desc:
     */
    @WebServlet(urlPatterns= "/userOutLoginServlet")
    public class userOutLoginServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
            //获取session对象
            HttpSession session = request.getSession();
            //手动去销毁session对象
            session.invalidate();
            request.getRequestDispatcher("/login.jsp").forward(request,response);
        }
    
    }

（userRegisterServlet）user注册功能的的实现，web层的代码：
    package cn.cyp.web;
    
    import cn.cyp.bean.User;
    import cn.cyp.dao.impl.userDaoImpl;
    import cn.cyp.service.impl.userServiceImpl;
    import cn.cyp.service.userService;
    import org.apache.commons.beanutils.BeanUtils;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import java.io.IOException;
    import java.lang.reflect.InvocationTargetException;
    import java.util.Map;
    
    /**
     * @Author:cyp
     * @date:2019/8/19 15:12
     * @Desc:
     */
    @WebServlet(urlPatterns = "/userRegisterServlet")
    public class userRegisterServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            String img = request.getParameter("img");
            //创建session对象
            HttpSession session = request.getSession();
            String code = (String)session.getAttribute("code");
            //进行判断输入框的内容和验证码是否一致
            if(!code.equalsIgnoreCase(img)) {
                request.setAttribute("imgmsg","验证码错误");
                request.getRequestDispatcher("/register.jsp").forward(request,response);
                return;
            }
            Map<String, String[]> map = request.getParameterMap();
            User user = new User();
            try {
                BeanUtils.populate(user,map);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            }
            //进行判断用户名和密码不能为空
            if(user.getUsername()==null||user.getPwd()==null||user.getUsername()==""||user.getPwd()==""){
                     request.getRequestDispatcher("/register.jsp").forward(request,response);
            }
            //进行判断该用户是否存在
            userService userService = new userServiceImpl();
            Boolean flag = userService.registerUser(user);
            if (flag) {
                System.out.println("添加成功");
                request.getRequestDispatcher("login.jsp").forward(request,response);
            }else {
                System.out.println("添加失败");
            }
        }
    }

**jsp部分的代码**

(addCustomer.jsp)添加用户的页面
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <html>
    <head>
        <title>Title</title>
        <link href="css/bootstrap.min.css" rel="stylesheet">
        <script src="js/jquery/1.11.3/jquery.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
        <script>
            function check() {
                //验证年龄
                var  age = document.getElementById("ageid");
                if(isNaN(age.value)){
                    document.getElementById("spanage").innerHTML="年龄只能是数字";
                    return false;
                }
                if(age.value.length==0){
                    document.getElementById("spanage").innerHTML="年龄不能为空";
                    return false;
                }
                //验证邮箱
                var emailid = document.getElementById("emailid");
                //不区分邮箱大小写
                var regExp = /^([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})$/
                if (!regExp.test(emailid.value)) {
                document.getElementById("spanemail").innerHTML="请输入正确的邮箱";
                    return false;
                }
                    return true;
            }
        </script>
    </head>
    <body>
    <h2 align="center">请输入添加用户信息</h2>
    <div style="text-align:center;padding-left: 300px" class="container table-responsive">
        <form action="${pageContext.request.contextPath}/addCustomerServlet" method="post" onsubmit="return check()">
            <table  class="table table-bordered table-hover" style="width: 600px;">
                <tr>
                    <td>姓名：</td>
                    <td><input type="text" name="name" id="nameid" value="${old.name}" ></td>
                </tr>
                <tr>
                    <td>性别：</td>
                    <td>
                        <input type="radio" checked="checked" name="sex" value="女"
                                <c:if test="${old.sex=='女'}">checked</c:if>
                        />女
                        <input type="radio" name="sex" value="男"
                               <c:if test="${old.sex=='男'}">checked</c:if>/>男
                    </td>
                </tr>
                <tr>
                    <td>年龄：</td>
                    <td>
                        <input type="text" name="age" id="ageid" value="${old.age}">
                        <span id="spanage" style="color: red"></span>
                    </td>
                </tr>
                <tr>
                    <td>籍贯：</td>
                    <td>
                        <select name="addr" id="addrid">
                            <option value="河南省" selected="selected" <c:if test="${old.addr=='河南省'}">selected</c:if>>河南省</option>
                            <option value="郑州" <c:if test="${old.addr=='郑州'}">selected</c:if>>郑州</option>
                            <option value="开封" <c:if test="${old.addr=='开封'}">selected</c:if>>开封</option >
                            <option value="商丘" <c:if test="${old.addr=='商丘'}">selected</c:if>>商丘</option>
                        </select>
                    </td>
                </tr>
                <tr>
                    <td>qq：</td>
                    <td><input type="text" name="qq" id="qqid" value="${old.qq}"></td>
                </tr>
                <tr>
                    <td>邮箱：</td>
                    <td>
                        <input type="text" name="email" id="emailid" value="${old.email}">
                        <span id="spanemail"style="color: red">${msg}</span>
                    </td>
                </tr>
                <tr>
                    <td colspan="2">
                        <input type="submit" class="btn btn-primary" value="提交">
                        <input type="reset" class="btn btn-primary" value="重置">
                        <a  class="btn btn-primary" href="${pageContext.request.contextPath}/pageBeanServlet">返回</a>
                    </td>
                </tr>
            </table>
        </form>
    </div>
    </body>
    </html>

**（list.jsp）显示首页面**
        
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Bootstrap 101 Template</title>
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <script src="js/jquery/1.11.3/jquery.min.js"></script>
    <script src="js/bootstrap.min.js"></script>
    <script>
        //获取全选/全不选的id
        function checkall() {
            var checkinputid = document.getElementById("checkinputid");
            //   获取所有名字为id的对象
            var items = document.getElementsByName("items");
            //    进行循环遍历
            for (var i = 0; i < items.length; i++) {
                //使得全选，全不选的内容为选中，选不中
                items[i].checked = checkinputid.checked;
            }
        }
    
        function isdelete() {
            //是否删除所选的内容
            var b = window.confirm("您确定删除吗？");
            if (b) {
                alert("确定");
            } else {
                alert("取消")
            }
        }
    
        //    进行判断有没有选择复选框
        window.onload = function () {
            document.getElementById("selectdelete").onclick = function () {
                //    取得所有选中的checkbox
                var items = document.getElementsByName("items");
                var str = "";
                //遍历checkbox
                for (var i = 0; i < items.length; i++) {
                    if (items[i].checked == true) {
                        str += items[i].value + ",";
                    }
                }
                if (str == "") {
                    alert("请先选择复选框")
                } else {
                    var b = window.confirm("确定要删除编号：" + str);
                    if (b) {
                        document.getElementById("formid").submit();
                    }
                }
            }
        }
        //    分页的方法
        function go(pageNum) {
            location.href = "${pageContext.request.contextPath}/pageBeanServlet?name=${map.name[0]}&age=${map.age[0]}&sex=${map.sex[0]}&pageNum=" + pageNum;
        }
    </script>
    <head>
        <title>Title</title>
    </head>
    <body>
    <%--<form action="${pageContext.request.contextPath}/deleteCheckedCustomerServlet" method="post">--%>
    <div class="row">
        <div class="col-lg-1"></div>
        <div class="col-lg-6">
            欢迎<font size="5px" color="red">${sessionScope.username}</font>登陆：
        </div>
    </div>
    
    <div class="row">
        <div class="col-lg-1"></div>
        <div class="col-lg-6">
            <a href="${pageContext.request.contextPath}/userOutLoginServlet"><font size="3px" color="red">注销</font></a>
        </div>
    </div>
    <h1 style="text-align: center;color: red">用户管理系统</h1>
    <div class=" container" style="margin-top: 60px;">
        <div class="container" style="margin-top: 20px;margin-bottom: 10px">
            <%--模糊查询--%>
    
            <div class="row">
                <form action="${pageContext.request.contextPath}/pageBeanServlet" method="post">
                    <div class="col-lg-2">
                        <input type="text" class="form-control" name="name" value="${map.name[0]}" placeholder="按姓名查">
                    </div>
                    <div class="col-lg-2">
                        <input type="text" class="form-control" name="age" value="${map.age[0]}" placeholder="按年龄查">
                    </div>
                    <div class="col-lg-2">
                        <input type="text" class="form-control" name="sex" value="${map.sex[0]}" placeholder="按性别查">
                    </div>
    
                    <div class="col-lg-3">
                        <%--onclick='window.location.href<c:if test="${pageBean.totalCounts==0}">="index.jsp"</c:if>'--%>
                        <input type="submit" class="btn btn-warning btn-md " value="查询" >
                    </div>
                </form>
                <div class="col-lg-3" style="padding-right: 0px">
                    <a class="btn btn-primary" href="addCustomer.jsp">添加客户</a>
                    <a class="btn btn-primary" href="javaScript:void(0);" id="selectdelete">删除客户</a>
                    <%--<button class="btn btn-primary" onclick="javascript:window.location.reload();" >刷新</button>--%>
                    <a class="btn btn-primary" href="${pageContext.request.contextPath}/pageBeanServlet">刷新</a>
                    <%--<input type="submit" class="btn btn-primary" value="删除选中" onclick="isdelete()">--%>
                </div>
            </div>
        </div>
        <form id="formid" action="${pageContext.request.contextPath}/deleteCheckedCustomerServlet" method="post">
            <table class="table table-bordered table-hover" <c:if test="${pageBean.totalCounts==0}">hidden</c:if> >
                <tr class="success">
                    <th>
                        <input type="checkbox" id="checkinputid" onclick="checkall()">全选/全不选
                    </th>
                    <th>编号</th>
                    <th>姓名</th>
                    <th>性别</th>
                    <th>年龄</th>
                    <th>籍贯</th>
                    <th>qq</th>
                    <th>邮箱</th>
                    <th>操作</th>
                </tr>
                <c:forEach items="${requestScope.pageBean.list}" var="list">
                    <tr>
                        <td>
                            <input type="checkbox" name="items" id="items" value="${list.id}">
                        </td>
                        <td>${list.id}</td>
                        <td>${list.name}</td>
                        <td>${list.sex}</td>
                        <td>${list.age}</td>
                        <td>${list.addr}</td>
                        <td>${list.qq}</td>
                        <td>${list.email}</td>
                        <td>
                            <a class="btn btn-default btn-lg"
                               href="${pageContext.request.contextPath}/updateCustomerServlet?id=${list.id}">修改</a> 
                            <a class="btn btn-default btn-lg"
                               href="${pageContext.request.contextPath}/deleteCustomerServlet?id=${list.id}">删除</a></td>
                    </tr>
                </c:forEach>
            </table>
        </form>
        <%--分页--%>
        <%--如果在数据库没有搜到相关信息，提示一句话"未查到相关信息"--%>
        <div <c:if test="${pageBean.totalCounts!=0}">hidden</c:if> >
        <span style="color: red;font-size: 40px;text-align: center">未查询到内容</span>
        </div>
        <div>
            <nav class="nav1">
                <ul class="pagination pagination-lg">
                    <li>
                        <span>当前页${pageBean.pageNum}/${pageBean.totalPages}</span>
                        <a <c:if test="${pageBean.totalCounts==0}">hidden</c:if> href="javascript:void(0);" onclick="go(1)">首页</a>
                        <a <c:if test="${pageBean.totalCounts==0}">hidden</c:if> href="javascript:void(0);" onclick="go(${pageBean.beforePage})" aria-label="Previous">
                            <span aria-hidden="true">上一页</span>
                        </a>
                    </li>
                    <%--分页栏--%>
                    <c:forEach items="${pageBean.pageBar}" var="bar">
                        <c:if test="${pageBean.pageNum==bar}">
                            <%--显示激活状态active--%>
                            <li class="active"><a href="">${bar}</a></li>
                        </c:if>
                        <c:if test="${pageBean.pageNum!=bar}">
                            <li class=""><a href="javascript:void(0)" onclick="go(${bar})">${bar}</a></li>
                        </c:if>
                    </c:forEach>
                    <li>
                       <%--判断最大条数是不是0--%>
                        <a <c:if test="${pageBean.totalCounts==0}">hidden</c:if> href="javascript:void(0);" onclick="go(${pageBean.nextPage})" aria-label="Next">
                            <span aria-hidden="true">下一页</span>
                            <a <c:if test="${pageBean.totalCounts==0}">hidden</c:if> href="javascript:void(0);" onclick="go(${pageBean.totalPages})">尾页</a>
                            <span>共${pageBean.totalCounts}条</span>
                        </a>
                    </li>
                </ul>
            </nav>
        </div>
    </div>
    </body>
    </html>

（login.jsp）登陆界面
    
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>Title</title>
        <link href="css/bootstrap.min.css" rel="stylesheet">
        <script src="js/jquery/1.11.3/jquery.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
        <script>
            //传到submit中的条件
            function demo1() {
                var inputusername = document.getElementById("inputusername");
                var inputpwd = document.getElementById("inputpwd");
                if ((inputusername.value=="") || (inputpwd.value=="")){
                    alert("请检查您的用户名和密码");
                    return false;
                }
                return true;
            }
    
            function demo() {
                var img = document.getElementById("_img");
                //通过拼接字符串的方式，对验证码进行切换
                img.src="${pageContext.request.contextPath}/checkCodeServlet?"+new Date().getTime();
            }
        </script>
    </head>
    <body background="img/bg3.jpg" style="width: 100%" >
    <div class="row" style="padding-top: 50px">
        <div class="col-lg-5"></div>
        <div class="col-lg-2"><h1>管理员登陆</h1></div>
    </div>
    <div class="container" style="padding-left: 250px ;padding-top: 50px;">
        <form class="form-horizontal" action="${pageContext.request.contextPath}/userLoginTestServlet"  method="post"
              onsubmit="return demo1();">
            <div class="form-group">
                <label for="inputusername" class="col-lg-2 control-label">用户名</label>
                <div class="col-lg-4">
                    <input type="text" class="form-control" name="username" id="inputusername" placeholder="请输入用户名">
                </div>
            </div>
            <div class="form-group">
                <label for="inputPassword" class="col-lg-2 control-label">密码</label>
                <div class="col-lg-4">
                    <input type="password" class="form-control" name="pwd" id="inputPassword" placeholder="请输入密码">
                </div>
                <div class="“col-lg-2">
                    <span id="spanid"></span>
                </div>
            </div>
            <div class="form-inline">
                <label for="checkcode" class="col-lg-2 control-label">验证码</label> 
                <input type="text" class="form-control" name="img" id="checkcode" placeholder="请输入验证码">
                <img src="${pageContext.request.contextPath}/checkCodeServlet" id="_img"  onclick="demo()">
                ${requestScope.imgmsg}
            </div>
            <div class="form-group" style="margin-top: 10px;margin-left: 10px">
                <div class="col-lg-offset-2 col-lg-10">
                    <input type="submit" class="btn btn-primary" value="登陆">
                    没有账号，点击<a class="" href="register.jsp" style="text-decoration: none">注册</a>
                </div>
            </div>
        </form>
    </div>
    </body>
    </html>

（register.jsp)注册界面
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>Title</title>
        <link href="css/bootstrap.min.css" rel="stylesheet">
        <script src="js/jquery/1.11.3/jquery.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
        <script>
            //检查验证码是否一致
            function demo200() {
                var _img = document.getElementById("_img");
                //通过拼接字符串的方式，对验证码进行切换
                _img.src = "${pageContext.request.contextPath}/Checkcode?" + new Date().getTime();
            }
    
            <%--清除所有框的历史记录--%>
            window.onload = function () {
                var tagName = document.getElementsByTagName("input");
                for (var i = 0; i < tagName.length; i++) {
                    tagName[i].setAttribute("autocomplete", "off");
                }
            }
            //返回的一个方法的true或者false结果
            function checkdemo(){
    
            <%--检查输入的用户名是否符合要求--%>
            var username = document.getElementById("inputname");
            var regUsername=/^[a-zA-Z][a-zA-Z0-9]{3,15}$/;
            if (!regUsername.test(username.value)) {
                document.getElementById("strongid").innerHTML ="用户名由英文字母和数字组成的4-16位字符，以字母开头";
                return false;
            }
                //检查密码的格式是否正确
                /*密码验证*/
                   var inputPassword1 = document.getElementById("inputPassword1");
                    var regpwd=/^[a-zA-Z0-9]{4,10}$/;
                    if(!regpwd.test(inputPassword1.value)){
                        document.getElementById("strongid").innerHTML="密码不能含有非法字符，长度在4-10之间";
                        return false;
                    }
                //检查两次输入的密码是否一致
                var inputPassword2 = document.getElementById("inputPassword2");
                if (inputPassword1.value != inputPassword2.value) {
                    document.getElementById("strongid").innerHTML = "两次输入的密码不一致";
                    return false;
                }
                return true;
            }
        </script>
    </head>
    <body background="img/bg3.jpg" style="width: 100%">
    <div class="row" style="padding-top: 50px">
        <div class="col-lg-5"></div>
        <div class="col-lg-2"><h1>管理员注册</h1></div>
    </div>
    <div class="container" style="padding-left: 250px ;padding-top: 50px;">
        <form class="form-horizontal" action="${pageContext.request.contextPath}/userRegisterServlet" method="post"
              onsubmit="return checkdemo()">
            <div class="form-group">
                <label for="inputname" class="col-lg-2 control-label">用户名</label>
                <div class="col-lg-4">
                    <input type="text" class="form-control" name="username" id="inputname" placeholder="请输入用户名">
                </div>
            </div>
            <div class="form-group">
                <label for="inputNickname" class="col-lg-2 control-label">昵称</label>
                <div class="col-lg-4">
                    <input type="text" class="form-control" name="nickname" id="inputNickname" placeholder="请输入昵称">
                </div>
            </div>
            <div class="form-group">
                <label for="inputPassword1" class="col-lg-2 control-label">密码</label>
                <div class="col-lg-4">
                    <input type="password" class="form-control" name="pwd" id="inputPassword1" placeholder="请输入密码">
                </div>
                <div class="“col-lg-2">
                    <span id="spanid"></span>
                </div>
            </div>
            <div class="form-group">
                <label for="inputPassword2" class="col-lg-2 control-label">确认密码</label>
                <div class="col-lg-4">
                    <input type="password" class="form-control" id="inputPassword2" placeholder="请再次确认密码">
                </div>
            </div>
            <div class="form-inline">
                <label for="checkcode" class="col-lg-2 control-label">验证码</label> 
                <input type="text" class="form-control" name="img" id="checkcode" placeholder="请输入验证码">
                <img src="${pageContext.request.contextPath}/Checkcode" id="_img" onclick="demo200()">
            </div>
            <div class="form-group" style="margin-top: 10px;margin-left: 10px">
                <div class="col-lg-offset-2 col-lg-10">
                    <button type="submit" class="btn btn-primary">注册</button>
                    <button type="reset" class="btn btn-primary">重置</button>
                </div>
            </div>
            <div class="container" style="padding-left: 140px">
                <%--出错信息框--%>
                <div class="alert alert-warning alert-dismissible" role="alert" style="text-align: center;width: 350px;height: 50px">
                    <button type="button" class="close" data-dismiss="alert">
                        <span class="glyphicon glyphicon-remove"></span>
                    </button>
                    <strong id="strongid">${imgmsg}</strong>
                </div>
            </div>
        </form>
    </div>
    </body>
    </html>

(updateCustomer.jsp)修改用户的界面
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <html>
    <head>
        <title>Title</title>
        <link href="css/bootstrap.min.css" rel="stylesheet">
        <script src="js/jquery/1.11.3/jquery.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
        <script>
            <%--进行判断id，id不可被修改--%>
        </script>
    </head>
    <body>
    <h2 align="center">修改用户数据</h2>
    <div style="text-align:center;padding-left: 300px" class="container table-responsive">
        <form action="${pageContext.request.contextPath}/updateCustomerServlet" method="post">
            <table  class="table table-bordered table-hover" style="width: 600px;">
                <tr>
                    <td>id：</td>
                    <td>
                        <input type="text" name="id" value="${customer.id}" id="idid" readonly="readonly" onclick="demo()">
                        <span id="spanid" style="color: red">id不可被修改</span>
                    </td>
                </tr>
                <tr>
                    <td>姓名：</td>
                    <td><input type="text" name="name" value="${customer.name}" id="nameid"></td>
                </tr>
                <tr>
                    <td>性别：</td>
                    <td>
                    <input type="radio" checked="checked" name="sex" value="女"
                            <c:if test="${customer.sex=='女'}">checked</c:if>/>女
                    <input type="radio" name="sex" <c:if test="${customer.sex=='男'}">checked</c:if>  value="男"/>男
                    </td>
                </tr>
                <tr>
                    <td>年龄：</td>
                    <td>
                        <input type="text" name="age" value="${customer.age}" id="ageid">
                        <span id="spanage"style="color: red"></span>
                    </td>
    
                </tr>
                <tr>
                    <td>籍贯：</td>
                    <td>
                        <select name="addr" id="addrid">
                        <option value="河南省" selected="selected" <c:if test="${customer.addr=='河南省'}">selected</c:if>>河南省</option>
                        <option value="郑州" <c:if test="${customer.addr=='郑州'}">selected</c:if>>郑州</option>
                        <option value="开封" <c:if test="${customer.addr=='开封'}">selected</c:if>>开封</option >
                        <option value="商丘" <c:if test="${customer.addr=='商丘'}">selected</c:if>>商丘</option>
                    </select>
                    </td>
                </tr>
                <tr>
                    <td>qq：</td>
                    <td><input type="text" name="qq"  value="${customer.qq}" id="qqid"></td>
                </tr>
                <tr>
                    <td>邮箱：</td>
                    <td>
                        <input type="text" name="email" value="${customer.email}" id="emailid">
                        <span id="spanemail"style="color: red"></span>
                    </td>
                </tr>
                <tr>
                    <td colspan="2">
                        <input type="submit" class="btn btn-primary" value="提交">
                        <input type="reset"  class="btn btn-primary" value="重置">
                        <a class="btn btn-primary" href="${pageContext.request.contextPath}/pageBeanServlet">返回</a>
                    </td>
                </tr>
            </table>
        </form>
    </div>
    </body>
    </html>

工具类的编写  
需要验证码工具类（Checkcode），（checkCodeServlet），  
jdbc数据库（jdbcUtil），MD5Utils（加密），MyFilter.java（过滤器）  
为了解决页面显示乱码问题，配合myFilter.java过滤器进行配置web.xml  
配置web.xml如下代码：

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
             version="3.1">
        <display-name></display-name>
        
        <filter>
            <filter-name>MyFilter</filter-name>
            <filter-class>cn.cyp.util.MyFilter</filter-class>
            <init-param>
                <param-name>type</param-name>
                <param-value>text/html</param-value>
            </init-param>
            <init-param>
                <param-name>encoding</param-name>
                <param-value>utf-8</param-value>
            </init-param>
        </filter>
        <filter-mapping>
            <filter-name>MyFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
    
    
        <welcome-file-list>
            <welcome-file>index.jsp</welcome-file>
        </welcome-file-list>
    </web-app>

**工具类：jdbc**

jdbc连数据库：
    package cn.cyp.util;
    
    import com.alibaba.druid.pool.DruidDataSourceFactory;
    
    import javax.sql.DataSource;
    import java.io.InputStream;
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.Statement;
    import java.util.Properties;
    
    public class jdbcUtil {
        //    工具类的抽取
    //    定义成员们变量DataSource
        private static DataSource ds;
    
        static {
            Properties pro = null;
            try {
                //1.加载配置文件
                pro = new Properties();
                InputStream is = jdbcUtil.class.getClassLoader().getResourceAsStream("druid.properties");
                pro.load(is);
                //2.获取DataSource
                ds = DruidDataSourceFactory.createDataSource(pro);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        //获取连接
        public static Connection getConnection() throws Exception {
            return ds.getConnection();
        }
    
        //    释放资源
        public static void close(Connection conn, Statement stmt) {
            try {
                if (stmt != null) {
                    stmt.close();
                    stmt = null;//gc垃圾回收机制会优先处理这些对象
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            try {
                if (conn != null) {
                    conn.close();
                    conn = null;//gc垃圾回收机制会优先处理这些对象
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        public static void close(Connection conn, Statement stmt, ResultSet rs) {
            try {
                if (rs != null) {
                    rs.close();
                    rs = null;//gc垃圾回收机制会优先处理这些对象
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            try {
                if (stmt != null) {
                    stmt.close();
                    stmt = null;//gc垃圾回收机制会优先处理这些对象
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            try {
                if (conn != null) {
                    conn.close();
                    conn = null;//gc垃圾回收机制会优先处理这些对象
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        //获取连接池的办法
        public static DataSource getDataSource() {
            return ds;
        }
    }

**MD5Utils（加密）**

package cn.cyp.util;
    
    import java.security.MessageDigest;
    
    
    import java.security.MessageDigest;
    
    /*
     * 负责给字符串数据进行加密
     */
    public class MD5Utils {
    
    	public static String getPWD( String strs ){
    		/*
    		 * 加密需要使用JDK中提供的类
    		 */
    		StringBuffer sb = new StringBuffer();
    		try{
    			MessageDigest digest = MessageDigest.getInstance("MD5");
    
    			byte[] bs = digest.digest(strs.getBytes());
    
    			/*
    			 *  加密后的数据是-128 到 127 之间的数字，这个数字也不安全。
    			 *   取出每个数组的某些二进制位进行某些运算，得到一个具体的加密结果
    			 *
    			 *   0000 0011 0000 0100 0010 0000 0110 0001
    			 *  &0000 0000 0000 0000 0000 0000 1111 1111
    			 *  ---------------------------------------------
    			 *   0000 0000 0000 0000 0000 0000 0110 0001
    			 *   把取出的数据转成十六进制数
    			 */
    
    			for (byte b : bs) {
    				int x = b & 255;
    				String s = Integer.toHexString(x);
    				if( x > 0 && x < 16 ){
    					sb.append("0");
    					sb.append(s);
    				}else{
    					sb.append(s);
    				}
    			}
    
    		}catch( Exception e){
    			System.out.println("加密失败");
    		}
    		return sb.toString();
    	}
    
    }

**checkCodeServlet（验证码）**

package cn.cyp.util;
    
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.image.BufferedImage;
    import java.io.IOException;
    import java.util.Random;
    import javax.imageio.ImageIO;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /**
     * 验证码
     */
    @WebServlet(urlPatterns = "/checkCodeServlet")
    public class checkCodeServlet extends HttpServlet {
    	public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
    		
    		//服务器通知浏览器不要缓存
    		response.setHeader("pragma","no-cache");
    		response.setHeader("cache-control","no-cache");
    		response.setHeader("expires","0");
    		
    		//在内存中创建一个长80，宽30的图片，默认黑色背景
    		//参数一：长
    		//参数二：宽
    		//参数三：颜色
    		int width = 80;
    		int height = 30;
    		BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
    		
    		//获取画笔
    		Graphics g = image.getGraphics();
    		//设置画笔颜色为灰色
    		g.setColor(Color.GRAY);
    		//填充图片
    		g.fillRect(0,0, width,height);
    		
    		//产生4个随机验证码，12Ey
    		String checkCode = getCheckCode();
    		//将验证码放入HttpSession中
    		request.getSession().setAttribute("CHECKCODE_SERVER",checkCode);
    		
    		//设置画笔颜色为黄色
    		g.setColor(Color.YELLOW);
    		//设置字体的小大
    		g.setFont(new Font("黑体",Font.BOLD,24));
    		//向图片上写入验证码
    		g.drawString(checkCode,15,25);
    		
    		//将内存中的图片输出到浏览器
    		//参数一：图片对象
    		//参数二：图片的格式，如PNG,JPG,GIF
    		//参数三：图片输出到哪里去
    		ImageIO.write(image,"PNG",response.getOutputStream());
    	}
    	/**
    	 * 产生4位随机字符串 
    	 */
    	private String getCheckCode() {
    		String base = "0123456789ABCDEFGabcdefg";
    		int size = base.length();
    		Random r = new Random();
    		StringBuffer sb = new StringBuffer();
    		for(int i=1;i<=4;i++){
    			//产生0到size-1的随机值
    			int index = r.nextInt(size);
    			//在base字符串中获取下标为index的字符
    			char c = base.charAt(index);
    			//将c放入到StringBuffer中去
    			sb.append(c);
    		}
    		return sb.toString();
    	}
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		this.doGet(request,response);
    	}
    }

MyFilter.java（过滤器）

package cn.cyp.util;
    
    import java.io.IOException;
    import java.io.UnsupportedEncodingException;
    import java.util.Map;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletRequestWrapper;
    import javax.servlet.http.HttpServletResponse;
    /**
     * 解决乱码问题
     * @author Administrator
     *
     */
    public class MyFilter implements Filter {
    	
    	private String type;
    	private String encoding;
    	
    	@Override
    	public void destroy() {
    		// 容器正常关闭 该方法会被执行..
    	}
    
    	@Override
    	public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
    		// TODO Auto-generated method stub
    		HttpServletRequest request = (HttpServletRequest) req;
    		HttpServletResponse response = (HttpServletResponse) res;
    		// 过滤器业务方法编写 默认 拦截后续资源的访问的
    		// 重写getParameter 方法!
    		// 思想: 自己编写 HttpServletRequest接口实现类 覆盖getParameter 方法 自己定义解码 utf-8
    		MyRequest myrequest = new MyRequest(request);// 构造方法注入 对象
    		response.setContentType(type+";charset="+encoding);// perperties xml
    		// class MYRequest implements HttpServletRequest /{ getParamter getParameterValue getParam..Map}
    		// 自己定义request 具备 getParameter系统方法 重写 保留 request其他api 的使用
    		chain.doFilter(myrequest, response);// request response 传递下去 ... 将request response 对象传递后续 servlet /jsp
    	}
    
    	@Override
    	public void init(FilterConfig config) throws ServletException {
    		type = config.getInitParameter("type");
    		encoding = config.getInitParameter("encoding");
    	}
    
    }
    
    // 找接口 中间类 Wrapper 包装类 加强 paramter 默认iso-8859-1 继承 HttpServletRequestWrapper 加强 getParameterXX sun 公司 设计类
    class MyRequest extends HttpServletRequestWrapper {
    	private HttpServletRequest request;// 获取 为加强 request 对象
    	private boolean flag = false;
    
    	public MyRequest(HttpServletRequest request) {
    		super(request);
    		// TODO Auto-generated constructor stub
    		this.request = request;
    	}
    
    	@Override
    	public String getParameter(String name) {
    		// 首先获取请求方式 ... key 表单 input name 对应属性值 value 表单用户提交信息数据 String[]
    		Map<String, String[]> map = getParameterMap();
    		if (map != null && map.size() != 0) {
    			String[] values = map.get(name);
    			if (values != null && values.length != 0) {
    				return values[0];
    			}
    		}
    		return super.getParameter(name);
    	}
    
    	@Override
    	public String[] getParameterValues(String name) {
    		Map<String, String[]> map = getParameterMap();
    		if (map != null && map.size() != 0) {
    			String[] values = map.get(name);
    			if (values != null && values.length != 0) {
    				return values;
    			}
    		}
    		return super.getParameterValues(name);
    	}
    
    	@Override
    	public Map getParameterMap() {
    		// get/post
    		String method = request.getMethod();
    		if ("post".equalsIgnoreCase(method)) {
    			try {
    				request.setCharacterEncoding("utf-8");
    				return request.getParameterMap();
    			} catch (UnsupportedEncodingException e) {
    				e.printStackTrace();
    			}
    		}
    		// 后续代码调用 getParameter getParameterValues 重复调用 getParameterMap
    		// 引入标记 开关 boolean 1--100 素数 双色球 6 1 1-33 6个红球 01 02 ...33 08
    		if ("get".equalsIgnoreCase(method)) {
    			if (!flag) {
    				// 必须要获取 map 遍历map 将 String[] 值获取 每一个数组元素都要 先编码后解码
    				Map<String, String[]> map = request.getParameterMap();// 原始request 获取数据 iso-88590-1解码
    				if (map != null && map.size() != 0) {
    					for (String key : map.keySet()) {
    						// 每一次循环 获取 map key
    						String[] values = map.get(key);
    						if (values != null && values.length != 0) {
    							// 先编码 后解码 forIn 简化查询
    							for (int i = 0; i < values.length; i++) {
    								try {
    									values[i] = new String(values[i].getBytes("iso-8859-1"), "utf-8");
    								} catch (UnsupportedEncodingException e) {
    									e.printStackTrace();
    								}
    							}
    						}
    					}
    				}
    				flag = true;
    				return map;
    			}
    		}
    		return super.getParameterMap();// 其他的请求
    	}
    
    }

[https_download.csdn.net_download_weixin_44476520_13087005]: https://download.csdn.net/download/weixin_44476520/13087005