一个简单的java web项目

小灰灰 2021-01-24 02:35 735阅读 0赞

这周因为要准备java和四级考试,所以没有做什么太多的东西,只是把我们之前做的javaweb项目又重新写了一下,现在就简单的说一下我做的东西.

我做的就是一个简单的用户注册和管理员页面.下面是我项目的一个简单的框架.

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下面我就一个删除的操作简单的说明一下,因为其他的大概都是一样的.

1,首先数据库要连接,我这里连接的是MySQL,也就是我上面的那个utils包里的java类,就是我的连接数据库的代码.

package com.qmx.web.utils; 
       
       import java.sql.Connection; 
       import java.sql.DriverManager; 
       import java.sql.SQLException; 
       
       public class DBUtils { 
       static String loginName = "root"; 
       static String loginPassword = "123456"; 
       static{ 
       try { 
       Class.forName("com.mysql.jdbc.Driver"); 
       } catch (ClassNotFoundException e) { 
       e.printStackTrace(); 
       } 
       } 
       
       public static Connection GetConnection() throws SQLException{ 
       String url = "jdbc:mysql://localhost:3306/webdb"; 
       return DriverManager.getConnection(url, loginName, loginPassword); 
       } 
       public static void main(String args[]) throws SQLException{ 
       System.out.println(GetConnection()); 
       } 
       
       }

2,接下来是要准备好操作的对象,也就是我项目里面的User类

package com.qmx.web.pro; 
       
       public class User { 
       private int id; //编号 
       private String name; //姓名 
       private String sex; //性别 
       private int age; //年龄 
       private String profess;//专业 
       private String grade; //年级 
       private String phone; //电话 
       
       public User() { 
       
       } 
       
       public User(String name, String sex, int age, String profess, String grade, String phone) { 
       this.name = name; 
       this.sex = sex; 
       this.age = age; 
       this.profess = profess; 
       this.grade = grade; 
       this.phone = phone; 
       } 
       
       public int getId() { 
       return id; 
       } 
       public void setId(int id) { 
       this.id = id; 
       } 
       public String getName() { 
       return name; 
       } 
       public void setName(String name) { 
       this.name = name; 
       } 
       public String getSex() { 
       return sex; 
       } 
       public void setSex(String sex) { 
       this.sex = sex; 
       } 
       public int getAge() { 
       return age; 
       } 
       public void setAge(int age) { 
       this.age = age; 
       } 
       public String getProfess() { 
       return profess; 
       } 
       public void setProfess(String profess) { 
       this.profess = profess; 
       } 
       public String getGrade() { 
       return grade; 
       } 
       public void setGrade(String grade) { 
       this.grade = grade; 
       } 
       public String getPhone() { 
       return phone; 
       } 
       public void setPhone(String phone) { 
       this.phone = phone; 
       } 
       @Override 
       public String toString() { 
       return "User [id=" + id + ", name=" + name + ", sex=" + sex + ", age=" + age + ", profess=" + profess 
       + ", grade=" + grade + ", phone=" + phone + "]"; 
       } 
       }

3,接下来就是定义我的接口以及实现接口,这个项目用到的主要知识是dao工厂模式.主要的我目前搞的也不是很清楚,但是大概会那么用.

package com.qmx.web.common; 
       
       import java.sql.SQLException; 
       import java.util.List; 
       
       public interface IBaseDao <K,V> { 
       
       public boolean doInsert(V v) throws SQLException; 
       
       public boolean doDelete(K id) throws SQLException; 
       
       public boolean doUpdate(V v) throws SQLException; 
       
       public V findById(K id) throws Exception; 
       
       public List <V> findAll() throws SQLException; 
       
       public List <V> findAllPaging(String column,String keyWord,int currentPage,int pageSize); 
       
       
       }

package com.qmx.web.dao; 
       
       import com.qmx.web.common.IBaseDao; 
       import com.qmx.web.pro.User; 
       
       public interface UserDao extends IBaseDao <String,User>{ 
       
       }

下面这个代码仅仅是我实现的删除的代码,不是全部,主要就是UserDaoimpl类实现UserDao接口,
````
public class UserDaoImpl implements UserDao

@Override 
       public boolean doDelete(String id) throws SQLException { 
       conn = DBUtils.GetConnection(); 
       String sql = "delete from user where name = ?"; 
       ps = conn.prepareStatement(sql); 
       ps.setString(1, id); 
       if(ps.executeUpdate() > 0){ 
       if(ps != null) 
       ps.close(); 
       if(conn != null) 
       conn.close(); 
       return true; 
       } 
       return false; 
       }
````
下面是service包中的方法

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5,然后是创建一个简单servlet,继承HttpServlet类，并实现doGet、doPost方法

package com.qmx.web.controller; 
       
       import java.io.IOException; 
       
       import javax.servlet.ServletException; 
       import javax.servlet.http.HttpServlet; 
       import javax.servlet.http.HttpServletRequest; 
       import javax.servlet.http.HttpServletResponse; 
       
       import com.qmx.web.service.UserService; 
       
       public class DelServlet extends HttpServlet { 
       
       private static final long serialVersionUID = 1L; 
       
       @Override 
       protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
       String name = req.getParameter("name"); 
       UserService userService = new UserService(); 
       try { 
       if(userService.doDelete(name)){ 
       req.getRequestDispatcher("delsuccess.jsp").forward(req, resp); 
       }else{ 
       req.getRequestDispatcher("delfail.jsp").forward(req, resp); 
       } 
       } catch (Exception e) { 
       // TODO: handle exception 
       e.printStackTrace(); 
       } 
       } 
       
       }

上面的我是使用了doGet()方法,因为我后面的jsp文件使用了a链接来操作删除方法,使用a链接默认的方法是doGet()方法.

6,然后就是编写jsp文件了

7,之后别忘了要配置XML文件

<servlet> 
       <servlet-name>DelServlet </servlet-name> 
       <servlet-class>com.qmx.web.controller.DelServlet </servlet-class> 
       </servlet> 
       
       <servlet-mapping> 
       <servlet-name>DelServlet </servlet-name> 
       <url-pattern>/DelServlet </url-pattern> 
       </servlet-mapping>

8,之后如果没有其他的错误的话,项目就会成功

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