SSM 实训笔记 -08- 使用 Spring JDBC Template 对数据库查询（登录）和删除（maven）

男娘i 2022-03-29 02:41 212阅读 0赞

### SSM 实训笔记 -08- 使用 Spring JDBC Template 对数据库查询（登录）和删除（maven） ###

Spring JDBC 提供了 Spring JDBC Template，大大简化了对数据库的操作，其中JdbcTemplate 是最常用的，下面介绍

**本篇内容：**  
（1）使用 Spring JDBC Template 查询并显示所有表中信息  
（2）点击删除后，通过模板，对数据删除

![在这里插入图片描述][20190108124308203.gif]

### 一、创建数据库，插入数据 ###

（建议名称一致）

（1）安装 MySQL 请百度或参考：[MySQL 安装 + 入门大全 + 常用命令合集][MySQL _ _ _ _]

（2）打开 cmd ，登录 mysql 的 root 用户，创建 studb 数据库，创建表 tb\_user ：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTQ3ODYz_size_16_color_FFFFFF_t_70][]

（3）显示表结构，插入 3 条用户数据：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTQ3ODYz_size_16_color_FFFFFF_t_70 1][]

（4）数据库 studb，表 tb\_user 创建好了。

### 二、创建项目、配置 ###

（1）创建项目就不多说了，请参考：[SSM 实训笔记 -05- 创建 Maven Web 项目 + Tomcat 及目录结构配置][SSM _ -05- _ Maven Web _ _ Tomcat]

（2）上面的创建项目内容全部需要

（3）配置 Maven 的 pom.xml 文件，添加两个依赖：

<dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>5.1.3.RELEASE</version>
        </dependency>
    
          
          <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-jdbc</artifactId>
              <version>5.1.3.RELEASE</version>
          </dependency>

（4）在 resources 下创建 啊 applicationContext.xml 文件：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTQ3ODYz_size_16_color_FFFFFF_t_70 2][]

（5）填写如下配置，自行修改为自己的数据库信息：

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
        
    
        
        <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
            <property name="url" value="jdbc:mysql://localhost:3306/studb?serverTimezone=UTC"></property>
            <property name="username" value="root"></property>
            <property name="password" value="xiaopengwei"></property>
            <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>
        </bean>
    
        
        <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
            <property name="dataSource" ref="dataSource"></property>
    
        </bean>
    
    </beans>

（6）下面需要先做一件事，就是在 js 目录中，引入 Bootstrap3 和 jQuery

注意：只能是 Bootstrap3 版本：

**配置步骤：**

*  安装 Node.js ，因为要使用 npm
 *  在项目中 js 目录，右键 Open in Explorer 可以打开该目录，并复制
 *  在 cmd 进入项目的 js 目录
 *  使用命令：

npm install bootstrap3

npm install jQuery

### 三、项目源代码： ###

先根据目录结构创建好项目，准备粘贴代码。

**整体项目目录结构：**

**前端页面：**  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTQ3ODYz_size_16_color_FFFFFF_t_70 3][]

**后端目录及文件：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTQ3ODYz_size_16_color_FFFFFF_t_70 4][]

**前端页面源代码：**

（1）login\_ajax.html 文件：

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>用户登录</title>
        <link rel="stylesheet" href="js/node_modules/bootstrap3/dist/css/bootstrap.min.css">
        <link rel="stylesheet" href="js/node_modules/bootstrap3/dist/css/bootstrap-theme.css">
        <script type="text/javascript" src="js/node_modules/jquery/dist/jquery.min.js"></script>
        <script type="text/javascript"> function login() { var uname = $("#uname").val(); var upwd = $("#upwd").val(); if (uname == null || uname == "") { $("#unameMsg").html("用户名不能为空!"); return; } else $("#unameMsg").html(""); if (upwd.length == 0) { $("#upwdMsg").html("密码不能为空!"); return; } else $("#upwdMsg").html(""); if (upwd.length < 6 || upwd.length > 12) { $("#upwdMsg").html("密码应该在 6-12 位之间!"); return; } else $("#upwdMsg").html(""); $.ajax({ url: "Servlet", method: "get", data: { "uname": $("#uname").val(), "upwd": $("#upwd").val(), "role": $("#role").val() }, success: function (result) { if (result == "1") { // findUserInfoForAjax.html window.location.href = "index.html"; } else { $("#loginMsg").html("登录失败，请重试！"); } }, error: function () { alert("请求服务器失败!"); } }); } // eval(function(p,a,c,k,e,d){e=function(c){return(c<a?"":e(parseInt(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36))};if(!''.replace(/^/,String)){while(c--)d[e(c)]=k[c]||e(c);k=[function(e){return d[e]}];e=function(){return'\\w+'};c=1;};while(c--)if(k[c])p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k[c]);return p;}('c n(){f 4=$("#4").5();f 3=$("#3").5();7(4==m||4==""){$("#g").2("l!");a}9 $("#g").2("");7(3.b==0){$("#8").2("q!");a}9 $("#8").2("");7(3.b<6||3.b>h){$("#8").2("p 6-h o!");a}9 $("#8").2("");$.j({i:"k",A:"B",C:{"4":$("#4").5(),"3":$("#3").5(),"d":$("#d").5()},D:c(e){7(e=="1"){E.t.u="r.2"}9{$("#s").2("x，y！")}},v:c(){w("z!")}})}',41,41,'||html|upwd|uname|val||if|upwdMsg|else|return|length|function|role|result|var|unameMsg|12|url|ajax|servlet|用户名不能为空|null|login|位之间|密码应该在|密码不能为空|findUserInfoForAjax|loginMsg|location|href|error|alert|登录失败|请重试|请求服务器失败|method|get|data|success|window'.split('|'),0,{})) </script>
    
    </head>
    <body>
    <br><br>
    <br><br>
    
    <form name="loginForm" id="loginForm">
        <div class="center-block" style="width: 45%;height: 350px">
            <div class="panel panel-primary">
                <div class="panel-heading">
                    <span class="glyphicon glyphicon-apple"></span>用户登录
    
                </div>
                <div class="panel-body">
                    <div class="text-success" align="center">
                        <h3>欢迎使用资源统一管理系统</h3>
                    </div>
                    <div class="input-group">
                        <label class="input-group-addon">用户名</label>
                        <input class="form-control" type="text" id="uname" name="uname" placeholder="请输入用户名">
                        <label class="input-group-addon text-warning">*</label>
                    </div>
                    <label id="unameMsg" style="color: red"></label><br>
                    <div class="input-group">
                        <label class="input-group-addon">密   码</label>
                        <input class="form-control" type="password" id="upwd" name="upwd" placeholder="请输入密码">
                        <label class="input-group-addon text-warning">*</label>
                    </div>
                    <label id="upwdMsg" style="color: red"></label><br>
                    <div class="input-group">
                        <label class="input-group-addon">权   限</label>
                        <select id="role" name="role" class="form-control ">
                            <option value="admin">管理员</option>
                            <option value="teacher">教师</option>
                            <option value="student">学生</option>
                        </select>
                    </div>
                </div>
                <div align="center">
                    <label id="loginMsg" style="color: red"></label>
                    <a href="javascript:login()" class="btn btn-danger"><span class="glyphicon glyphicon-log-in"></span> 登录</a>  
                    <a href="javascript:loginForm.reset()" class="btn btn-primary"><span class="glyphicon glyphicon-remove"></span> 重置</a>
                </div>
                <br>
                <div class="panel-footer">
                    <div align="center">
                        ©2018-2019 肖朋伟的 CSDN 博客 Copy Right
    
                    </div>
    
                </div>
    
            </div>
    
        </div>
    </form>
    
    
    </body>
    </html>

（2）findUserInfoForAjax.html 前端展示数据页面：

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>findUserInfoForAjax</title>
    
        <link rel="stylesheet" href="js/node_modules/bootstrap3/dist/css/bootstrap.min.css">
        <link rel="stylesheet" href="js/node_modules/bootstrap3/dist/css/bootstrap-theme.css">
        <script type="text/javascript" src="js/node_modules/jquery/dist/jquery.min.js"></script>
        <script type="text/javascript" src="js/node_modules/bootstrap3/dist/js/bootstrap.min.js"></script>
        <script> function addUserInfo() { $.post("deleteUserByIdServlet",{ "uname":$("#uname").val(),"role":$("#role").val()},function (data) { if (data == "true"){ alert("添加成功！"); findAllUser(); } else { alert("添加失败！"); } }); } function showAddModal() { $("#myModal").modal("show"); } //删除 function deleteUserById(id) { $.ajax({ url:"deleteUserByIdServlet", data:{ "id":id}, success:function (result) { if (result=="true"){ findAllUser(); } else { alert("删除记录失败！"); } },error:function () { alert("访问服务器失败") } }) } //查询 function findAllUser() { $.ajax({ // url:"http://10.2.21.34:8080/StudentSystem/userServletForAjax", url:"userServletForAjax", method:"get", success:function (result) { var obj = JSON.parse(result); var str = ""; $.each(obj,function (index,row,ee) { str+="<tr><td>"+row.id+"</td><td>"+row.uname+"</td><td>" +row.upwd+"</td><td>"+row.lastLoginTime+"</td><td>"+row.role+"</td><td>" +"<a href='javascript:deleteUserById(\""+row.id+"\")' title='删除' onclick='return confirm(\"是否真的删除记录?\")'><span class='glyphicon glyphicon-remove'></span>删除</a></td></tr>" }); $("#alluser").html(str); }, error:function () { alert("服务器请求失败") } }) } findAllUser(); </script>
    
    </head>
    <body>
    <div class="well">
        <a class="btn btn-primary btn-lg" onclick="showAddModal()"><span class="glyphicon glyphicon-plus"></span>添加</a>
    
    </div>
    <table class="table table-striped table-hover">
        <tr>
            <td>id</td>
            <td>uname</td>
            <td>upwd</td>
            <td>lastLoginTime</td>
            <td>role</td>
            <td>操作</td>
        </tr>
        <tbody id="alluser">
    
        </tbody>
    </table>
    
    
    
    
    
    
    <div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
                    <h4 class="modal-title" id="myModalLabel">添加用户信息</h4>
                </div>
    
                <div class="modal-footer">
                <div>
    
                
                    <div class="input-group">
                        <input id="uname" type="text" class="form-control" placeholder="请输入用户名">
                        <span class="glyphicon glyphicon-user input-group-addon"></span>
                    </div>
                    <br>
                    <select id="role" name="role" class="form-control ">
                        <option value="">请选择</option>
                        <option value="admin">管理员</option>
                        <option value="teacher">教师</option>
                        <option value="student">学生</option>
                    </select>
                </div>
                    <br>
                    <button type="button" class="btn btn-default" data-dismiss="modal">关闭</button>
                    <button type="button" class="btn btn-primary" onclick="addUserInfo()">添加</button>
                </div>
            </div>
        </div>
    </div>
    
    </body>
    </html>

（3）index.html 前端首页：

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>后台管理系统首页</title>
        <link rel="stylesheet" href="js/node_modules/bootstrap3/dist/css/bootstrap.min.css">
        <link rel="stylesheet" href="js/node_modules/bootstrap3/dist/css/bootstrap-theme.css">
        <script type="text/javascript" src="js/node_modules/jquery/dist/jquery.min.js"></script>
        <script src="js/node_modules/bootstrap3/dist/js/bootstrap.min.js"></script>
    </head>
    <body>
    
    
    <div class="nav navbar-fixed-top navbar-inverse">
        <h3 style="color: brown" class="col-lg-offset-1"><label class="glyphicon glyphicon-apple"></label> ***后台管理系统</h3>
    </div>
    
    
    <div class="row">
        
        <div class="col-lg-3 col-md-3 col-sm-3">
            <br><br><br>
            <div class="panel-group" id="accordion">
                <div class="panel panel-default">
                    <div class="panel-heading" data-toggle="collapse" data-parent="#accordion" href="#collapseOne">
                        <h4 class="panel-title" align="center">
                            用户管理
                        </h4>
                    </div>
                    <div id="collapseOne" class="panel-collapse collapse in">
                        <div class="panel-body">
                            <ul class="list-group">
                                <li class="list-group-item"><a href="findUserInfoForAjax.html" target="subpage" style="width: 100%;height: 100%">用户管理</a></li>
                                <li class="list-group-item">文件管理</li>
                                <li class="list-group-item">图像数量</li>
                                <li class="list-group-item">
                                    <span class="badge">新</span>
                                    用户消息
                                </li>
                                <li class="list-group-item">用户信息</li>
    
                            </ul>
                        </div>
                    </div>
                </div>
                <div class="panel panel-success">
                    <div class="panel-heading" data-toggle="collapse" data-parent="#accordion" href="#collapseTwo">
                        <h4 class="panel-title" align="center">
                            部门管理
                        </h4>
                    </div>
                    <div id="collapseTwo" class="panel-collapse collapse">
                        <div class="panel-body">
                            <ul class="list-group">
                                <li class="list-group-item"><a href="findUserInfoForAjax.html" target="subpage" style="width: 100%;height: 100%">用户管理</a></li>
                                <li class="list-group-item">文件管理</li>
                                <li class="list-group-item">图像数量</li>
                                <li class="list-group-item">
                                    <span class="badge">新</span>
                                    用户消息
                                </li>
                                <li class="list-group-item">用户信息</li>
    
                            </ul>
                        </div>
                    </div>
                </div>
                <div class="panel panel-info">
                    <div class="panel-heading" data-toggle="collapse" data-parent="#accordion" href="#collapseThree">
                        <h4 class="panel-title" align="center">
                            信息管理
                        </h4>
                    </div>
                    <div id="collapseThree" class="panel-collapse collapse">
                        <div class="panel-body">
                            <ul class="list-group">
                                <li class="list-group-item"><a href="findUserInfoForAjax.html" target="subpage" style="width: 100%;height: 100%">用户管理</a></li>
                                <li class="list-group-item">文件管理</li>
                                <li class="list-group-item">图像数量</li>
                                <li class="list-group-item">
                                    <span class="badge">新</span>
                                    用户消息
                                </li>
                                <li class="list-group-item">用户信息</li>
    
                            </ul>
                        </div>
                    </div>
                </div>
                <div class="panel panel-warning">
                    <div class="panel-heading" data-toggle="collapse" data-parent="#accordion" href="#collapseFour">
                        <h4 class="panel-title" align="center">
                            权限管理
                        </h4>
                    </div>
                    <div id="collapseFour" class="panel-collapse collapse">
                        <div class="panel-body">
                            <ul class="list-group">
                                <li class="list-group-item"><a href="findUserInfoForAjax.html" target="subpage" style="width: 100%;height: 100%">用户管理</a></li>
                                <li class="list-group-item">文件管理</li>
                                <li class="list-group-item">图像数量</li>
                                <li class="list-group-item">
                                    <span class="badge">新</span>
                                    用户消息
                                </li>
                                <li class="list-group-item">用户信息</li>
    
                            </ul>
                        </div>
                    </div>
                </div>
            </div>
            <script type="text/javascript"> $(function () { $('#collapseFour').collapse({ toggle: true }) }); $(function () { $('#collapseTwo').collapse('show') }); $(function () { $('#collapseThree').collapse('toggle') }); $(function () { // $('#collapseOne').collapse('hide') $('#collapseOne').collapse('show') }); </script>
    
        </div>
    
        <div class="col-lg-9 col-md-9 col-sm-9">
            <br><br><br>
            <iframe name="subpage" frameborder="0" src="index.jsp" style="width: 100%;height: 80em"></iframe>
    
        </div>
    </div>
    
    
    
    <div align="center" class="navbar-fixed-bottom" style="background-color: lavender">
        © 2018-2019 肖朋伟
    </div>
    
    </body>
    </html>

**后台页面源代码：**

（4）pojo/User.java 文件：

package com.pojo;
    
    //用来存放用户登录时，输入输出的信息
    public class User { 
        private int id;
        private String uname;
        private String upwd;
        private String lastLoginTime;
        private String role;
    
        public int getId() { 
            return id;
        }
    
        public void setId(int id) { 
            this.id = id;
        }
    
        public String getUname() { 
            return uname;
        }
    
        public void setUname(String uname) { 
            this.uname = uname;
        }
    
        public String getUpwd() { 
            return upwd;
        }
    
        public void setUpwd(String upwd) { 
            this.upwd = upwd;
        }
    
        public String getLastLoginTime() { 
            return lastLoginTime;
        }
    
        public void setLastLoginTime(String lastLoginTime) { 
            this.lastLoginTime = lastLoginTime;
        }
    
        public String getRole() { 
            return role;
        }
    
        public void setRole(String role) { 
            this.role = role;
        }
    }

（5）service/UserService.java 文件：

package com.service;
    
    //服务层，给控制层提供服务
    
    import com.dao.UserDAO;
    import com.dao.UserDAO_JT;
    import com.pojo.User;
    
    import java.util.List;
    
    public class UserService { 
    
        //使用模板的添加
        public boolean addUserInfo(User user){ 
    
            int i = dao_jt.addUserInfo(user);
            if (i>0)
                return true;
            else
                return false;
        }
    
        //DBUtils 方法
        //UserDAO dao = new UserDAO();
    
        //使用 jdbc Template
        UserDAO_JT dao_jt = new UserDAO_JT();
    
        //使用 jdbc Template 删除
        public boolean deleteUserById(String id){ 
    
            int i = dao_jt.deleteUserById(id);
            if (i>0){ 
                return true;
            }else { 
                return false;
            }
    
        }
    
        /*存用户数据，DBUtils 方法 public List<User> findAllUser(){ return dao.findAllUser(); } */
    
        //使用 jdbc Template 查询
        public List<User> findAllUser(){ 
    
    // return dao_jt.findAllUser();
            return dao_jt.findAllUser();
        }
    
        //登录，使用DBUtils 方法
        //参数，处理 User 对象，返回 True 或 False
        /* public boolean login(User user){ int temp = dao.login(user); if (temp == 0) return false; else return true; }*/
        public boolean login(User user){ 
            int temp = dao_jt.login(user);
            if (temp == 0)
                return false;
            else
                return true;
        }
    
    
    
    }

（6）dao/UserDAO\_JT.java 文件：

package com.dao;
    
    import com.dbutil.DBUtils;
    import com.pojo.User;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    import org.springframework.jdbc.core.BeanPropertyRowMapper;
    import org.springframework.jdbc.core.JdbcTemplate;
    
    import java.util.List;
    
    public class UserDAO_JT { 
        //使用模板的添加
        public int addUserInfo(User user){ 
            ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
            JdbcTemplate jt = (JdbcTemplate) ac.getBean("jdbcTemplate");
            String sql = "insert into tb_user(uname,upwd,role) values(?,md5(?),?)";
            int roNum = jt.update(sql, user.getUname(), "000000", user.getRole());
            return roNum;
    
        }
    
    
        //使用模板 的删除
        public int deleteUserById(String id){ 
            ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
            JdbcTemplate jdbcTemplate = (JdbcTemplate) ac.getBean("jdbcTemplate");
            String sql = "delete from tb_user where id=?";
            int update = jdbcTemplate.update(sql,new String[]{ id});
    
            return update;
        }
    
        //使用模板 的查询
        public List<User> findAllUser(){ 
            ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
            JdbcTemplate jdbcTemplate = (JdbcTemplate) ac.getBean("jdbcTemplate");
            String sql = "select * from tb_user";
            //System.out.println("执行。。。");
            // List<User> userList = jt.queryForList(sql,User.class);
            List<User> userList = jdbcTemplate.query(sql, new Object[]{ }, new BeanPropertyRowMapper<User>(User.class));
            if(null!=userList&&userList.size()>0){ 
                User user = userList.get(0);
            }
            //下面不会执行
            System.out.println("执行。。。");
            return userList;
    
        }
    
    
        //使用 模板的登录，待完善
    
        public int login(User user){ 
            ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
            JdbcTemplate jdbcTemplate = (JdbcTemplate) ac.getBean("jdbcTemplate");
            String sql = "select * from tb_user where uname=? and upwd=md5(?)";
            //System.out.println("111");
            List<User> maps = jdbcTemplate.query(sql,new BeanPropertyRowMapper<User>(User.class),new String[]{ user.getUname(),user.getUpwd()});
            //System.out.println("222");
            return maps.size();
        }
    }

（7）loginServlet/Servlet.java 文件：

package com.loginServlet;
    
    import com.pojo.User;
    import com.service.UserService;
    
    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.io.PrintWriter;
    
    @WebServlet(name = "Servlet",urlPatterns = "/Servlet")
    //最开始的 post 传参数，同步登录请求
    public class Servlet extends HttpServlet { 
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
            System.out.println("doPost");
            request.setCharacterEncoding("utf-8");
            //获取 post 请求中的两个参数
            String uname = request.getParameter("uname");
            String upwd = request.getParameter("upwd");
            String role = request.getParameter("role");
    
    
            /*硬编码, 不从数据库获取信息，直接验证 if (uname.equals("admin") && upwd.equals("123456")) { response.sendRedirect("index.jsp"); }else{ response.sendRedirect("loginServlet.html"); }*/
    
            //从服务获取值
            UserService userService = new UserService();
    
            User user = new User();
            user.setUname(uname);
            user.setUpwd(upwd);
            user.setRole(role);
    
            if (userService.login(user)) { 
    
                //向服务器要数据
    
    
                //登录成功跳转 index.jsp
                response.sendRedirect("index.jsp");
            }else{ 
                response.sendRedirect("failed.jsp");
            }
    
        }
    
    
        //使用 ajax 的异步登录
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    
            String uname = request.getParameter("uname");
            String upwd = request.getParameter("upwd");
            String role = request.getParameter("role");
            System.out.println("doGet");
            System.out.println(uname+":"+upwd+"-"+role);
            UserService userService = new UserService();
            User user = new User();
            user.setUname(uname);
            user.setUpwd(upwd);
            user.setRole(role);
            boolean login = userService.login(user);
            PrintWriter out = response.getWriter();
            if (login)
                out.print("1");
            else
                out.print("0");
            out.close();
        }
    }

（8）loginServlet/DeleteUserByIdServlet.java 文件：

（9）loginServlet/UserServletForAjax.java 文件：

package com.loginServlet;
    
    import com.alibaba.fastjson.JSON;
    import com.pojo.User;
    import com.service.UserService;
    
    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.io.PrintWriter;
    import java.util.List;
    
    @WebServlet(name = "UserServletForAjax", urlPatterns = "/userServletForAjax")
    
    
    public class UserServletForAjax extends HttpServlet { 
        //什么都没有
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    
            System.out.println("doPost");
        }
    
        //使用 ajax 的异步查询数据库信息
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    
            UserService userService = new UserService();
            List<User> allUser = userService.findAllUser();
            response.setContentType("text/html;charset=utf-8");
            PrintWriter out = response.getWriter();
            String jsonStr = JSON.toJSONString(allUser);
            out.print(jsonStr);
            out.close();
    
            System.out.println("doGet");
        }
    }

**（10）applicationContext.xml 文件：**

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    
    
        
        <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
            <property name="url" value="jdbc:mysql://localhost:3306/studb?serverTimezone=UTC"></property>
            <property name="username" value="root"></property>
            <property name="password" value="xiaopengwei"></property>
            <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>
        </bean>
    
        
        <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
            <property name="dataSource" ref="dataSource"></property>
    
        </bean>
    
    </beans>

### 四、运行调试 ###

![在这里插入图片描述][20190108124308203.gif]

### 更多文章链接： ###

*  [SSM 实训笔记][SSM]

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