使用IDEA基于Maven搭建SSM（Spring+SpringMVC+MyBatis）框架并完成登录注册案例（附源码）

偏执的太偏执、 2024-04-17 19:37 45阅读 0赞

#### 目录 ####

*   *  一、环境准备
     *  二、框架搭建
     *  三、分析需求创建表并连接数据库
     *  四、添加前端页面
     *  五、完成前端与后台的交互

### 一、环境准备 ###

1.  开发工具：IntelliJ IDEA 2017.3.1 x64
2.  数据库：MySQL 5.5，其中MySQL的管理工具为Navicat
3.  JDK版本：JDK1.8
4.  Maven版本：apache-maven-3.2.2
5.  Tomcat版本：apache-tomcat-7.0.91  
    **当然了，以上只是我个人电脑上的开发环境，只要版本不过于老旧，应该是没有什么问题的。除此之外，有关于IDEA的基本操作以及JDK、Maven、Tomcat等的配置，这些也需要大家配置好（可以百度搜索一下）。本案例的完整代码会在文章末尾给出。**

### 二、框架搭建 ###

**1.使用IDEA创建一个基本的Maven工程**

（1）打开IDEA，点击Create New Project  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70]

(2)  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 1]

（3）  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 2]  
（4）  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 3]  
（5）进去之后的界面如下  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 4]  
（6）由于IDEA创建maven的Java web项目时，main文件夹下没有java，resources目录等源文件夹，所以我们需要自己创建，[具体过程可以查看这篇博客][Link 1]。这样一个基本的项目结构就创建好了。

**2.在pom.xml中添加该项目所需要依赖jar包**

<?xml version="1.0" encoding="UTF-8"?>
    
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
             http://maven.apache.org/maven-v4_0_0.xsd">
    
      <modelVersion>4.0.0</modelVersion>
      <packaging>war</packaging>
    
      <name>ssmtest</name>
      <groupId>com.test</groupId>
      <artifactId>ssmtest</artifactId>
      <version>1.0-SNAPSHOT</version>
    
      <build>
        <plugins>
          <plugin>
            <groupId>org.mortbay.jetty</groupId>
            <artifactId>maven-jetty-plugin</artifactId>
            <version>6.1.7</version>
            <configuration>
              <connectors>
                <connector implementation="org.mortbay.jetty.nio.SelectChannelConnector">
                  <port>8888</port>
                  <maxIdleTime>30000</maxIdleTime>
                </connector>
              </connectors>
              <webAppSourceDirectory>${project.build.directory}/${pom.artifactId}-${pom.version}</webAppSourceDirectory>
              <contextPath>/</contextPath>
            </configuration>
          </plugin>
        </plugins>
      </build>
    
      <dependencies>
        
    
        
        
    
        
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-webmvc</artifactId>
          <version>4.3.7.RELEASE</version>
        </dependency>
    
        
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-jdbc</artifactId>
          <version>4.3.7.RELEASE</version>
        </dependency>
    
        
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-aspects</artifactId>
          <version>4.3.7.RELEASE</version>
        </dependency>
    
        
        
        <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis</artifactId>
          <version>3.4.2</version>
        </dependency>
    
        
        
        <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis-spring</artifactId>
          <version>1.3.1</version>
        </dependency>
    
        
        
        <dependency>
          <groupId>c3p0</groupId>
          <artifactId>c3p0</artifactId>
          <version>0.9.1</version>
        </dependency>
    
        
        <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.41</version>
        </dependency>
    
        
        
        <dependency>
          <groupId>jstl</groupId>
          <artifactId>jstl</artifactId>
          <version>1.2</version>
        </dependency>
    
        
        <dependency>
          <groupId>javax.servlet</groupId>
          <artifactId>javax.servlet-api</artifactId>
          <version>3.0.1</version>
          
          <scope>provided</scope>
        </dependency>
    
        
        
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.12</version>
        </dependency>
    
        
        <dependency>
          <groupId>com.fasterxml.jackson.core</groupId>
          <artifactId>jackson-core</artifactId>
          <version>2.9.6</version>
        </dependency>
        <dependency>
          <groupId>com.fasterxml.jackson.core</groupId>
          <artifactId>jackson-annotations</artifactId>
          <version>2.9.6</version>
        </dependency>
        <dependency>
          <groupId>com.fasterxml.jackson.core</groupId>
          <artifactId>jackson-databind</artifactId>
          <version>2.9.6</version>
        </dependency>
        
      </dependencies>
    
    </project>

添加完成之后，刷新该工程  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 5]

这样便可以看见已经添加成功的jar包  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 6]

**3.配置web.xml文件**

<?xml version="1.0" encoding="UTF-8"?>
    
    <web-app version="2.4"
             xmlns="http://java.sun.com/xml/ns/j2ee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
             http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    
      
      <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath*:spring/spring-*.xml</param-value>
      </context-param>
      <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
      </listener>
    
    
      
      <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:spring/springmvc-context.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
      </servlet>
      <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>   
      </servlet-mapping>
    
    
      
      <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
          <param-name>encoding</param-name>
          <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
          <param-name>forceEncoding</param-name>
          <param-value>true</param-value>
        </init-param>
      </filter>
      <filter-mapping>
        <filter-name>encoding</filter-name>
        <servlet-name>springmvc</servlet-name>
      </filter-mapping>
    
    </web-app>

**4.在resource目录下分别创建spring和mybatis目录，并且添加相应的配置文件**  
![在这里插入图片描述][20190904191334806.png]  
（1）spring-context.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:tx="http://www.springframework.org/schema/tx"
           xmlns:aop="http://www.springframework.org/schema/aop"
           xmlns:mvc="http://www.springframework.org/schema/mvc"
           xsi:schemaLocation="http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
            http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
            http://www.springframework.org/schema/tx
            http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
            http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context-4.3.xsd
            http://www.springframework.org/schema/mvc
            http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    
        
        <context:component-scan base-package="com.test.*" >
            <context:exclude-filter type="annotation"
                                    expression="org.springframework.stereotype.Controller"/>
        </context:component-scan>
    
        
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
            <property name="driverClass" value="com.mysql.jdbc.Driver"/>
            <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/ssmtest?rewriteBatchedStatements=true&useUnicode=true&characterEncoding=utf8"/>
            <property name="user" value="root"/>
            <property name="password" value="15272595644"/>
        </bean>
    
        
        <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean" >
            <property name="configLocation" value="classpath:mybatis/config.xml" />
            <property name="dataSource" ref="dataSource" />
            <property name="mapperLocations" >
                <list>
                    <value>classpath*:mybatis/mapper-*.xml</value>
                </list>
            </property>
        </bean>
        
        <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer" >
            <property name="basePackage" value="com.test.dao" />
        </bean>
    
    
        
        <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            
            <property name="dataSource" ref="dataSource"/>
        </bean>
        <tx:advice id="transactionAdvice" transaction-manager="transactionManager" >
            <tx:attributes>
                <tx:method name="*" propagation="REQUIRED" isolation="DEFAULT" rollback-for="java.lang.Exception" />
                <tx:method name="query*" read-only="true" />
            </tx:attributes>
        </tx:advice>
        <aop:config>
            <aop:advisor advice-ref="transactionAdvice" pointcut="execution(* com..*Service.*(..))"/>
        </aop:config>
    
    
    </beans>

（2）springmvc-context.xml

（3）config.xml

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE configuration
            PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        <typeAliases>
    
        </typeAliases>
    </configuration>

(4)mapper-user.xml

**5.在java目录下创建一些基本的包**  
![在这里插入图片描述][20190905232742813.png]

<table> 
 <thead> 
  <tr> 
   <th>包名</th> 
   <th>作用</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>bean</td> 
   <td>存放一些实体类，有些一与数据库的表相对应，例如，用户类等等</td> 
  </tr> 
  <tr> 
   <td>controller</td> 
   <td>控制层</td> 
  </tr> 
  <tr> 
   <td>dao</td> 
   <td>数据传输层，与数据库进行交数据交互</td> 
  </tr> 
  <tr> 
   <td>service</td> 
   <td>编写 业务逻辑的接口</td> 
  </tr> 
  <tr> 
   <td>serviceImpl</td> 
   <td>实现业务逻辑</td> 
  </tr> 
 </tbody> 
</table>

当然了，每个人给包的命名或者结构安排可能不一样，我所给出的只是一种参考。

### 三、分析需求创建表并连接数据库 ###

1.由于本文的案例比较简单，只有用户的登录和注册功能，所以在名为ssmtest的数据库（自己在MySQL创建）中只建立了一张t\_user表，如下图所示。  
![在这里插入图片描述][20190905235327688.png]  
2.在IDEA中连接到该名为ssmtest的数据库  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 7]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 8]  
这样便连接成功了！与此同时在User.java中添加相应的属性  
**User.java**

package com.test.bean;
    
    public class User {
        
    
        private String username;
        private String password;
        //用于判断是否记住用户名
        private String flag;
    
        public String getFlag() {
        
            return flag;
        }
    
        public void setFlag(String flag) {
        
            this.flag = flag;
        }
    
        public String getUsername() {
        
            return username;
        }
    
        public void setUsername(String username) {
        
            this.username = username;
        }
    
        public String getPassword() {
        
            return password;
        }
    
        public void setPassword(String password) {
        
            this.password = password;
        }
    }

### 四、添加前端页面 ###

具体目录结构如下图所示  
![在这里插入图片描述][20190905235919152.png]  
**1.login.jsp**

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <%@ page import="com.test.utils.*" %>
    
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <title>登录页面</title>
        <link rel="stylesheet" href="./css/login.css">
    
    </head>
    
    <%
        //完成用户名的回显
        String username="";
        //获得从客户端携带过来的所有Cookie
        Cookie[] cookies=request.getCookies();
        //从Cookie的数组中查找指定名称的Cookie
        Cookie cookie = CookieUtils.findCookie(cookies, "username");
        if(cookie!=null)
        {
            username=cookie.getValue();
        }
    %>
    
    
    <body>
        <div class="login">
            <div class="header">
                <h1>
                    <a href="./login">登录</a> <a href="./register">注册</a>
                </h1>
            </div>
    
            <form action="" method="post">
                <table>
                    <tr>
                        <td class="td1">用户名</td>
                        <td><input type="text" class="input1" id="username" name="username" value="<%= username %>" placeholder="请输入用户名"></td>
                    </tr>
                    <tr>
                        <td class="td1">密码</td>
                        <td><input type="password" class="input1" id="password" name="password" placeholder="请输入密码"></td>
                    </tr>
                    <tr>
                        <td class="td1" colspan="2">
                            <input type="checkbox" name="rememberUsername" value="true" checked="checked"> 记住用户名</td>
                    </tr>
                    <tr>
                        <td colspan="2">
                            <div class="btn-red">
                                <input type="button" value="登录" id="login-btn" onclick="doLogin()">
                            </div>
                        </td>
                    </tr>
                </table>
            </form>
        </div>
    
        <script src="jquery/jquery-2.1.1.min.js"></script>
        <script src="layer/layer.js"></script>
    
    
        <script>
            //1.登录单击事件
            function doLogin(){
          
                //账号和密码的非空校验(使用jQuery做的id选择器)
                var username = $("#username").val();
                var password = $("#password").val();
    
                //表单元素的value取值不会为null，当为空时是空字符串
                if(username == "" || password==""){
          
                    //alert("用户登录账号或密码为空，请输入");
                    /*为了使弹出框的样式保持一致，不受浏览器的影响，可以使用组件layer
                    * layer.msg(arg1,arg2,arg3)
                    * arg1：提示信息
                    * arg2: time为弹出框持续的时间，单位为ms
                    *       icon为弹出框呈现的样式
                    *       shift为弹出框出现的样式
                    * arg3: 回调方法
                    * 具体细节可以参考layer文档
                    * */
                    layer.msg("用户登录账号或密码为空，请输入", {
          time:2000, icon:5, shift:6}, function(){
          });
                    return;
                }
    
                var rememberUsername = document.getElementsByName("rememberUsername");
                var flag = rememberUsername[0].checked;
    
                //提交表单
                var loadingIndex=null;
                $.ajax({
          
                    type:"POST",
                    url:"doAjaxLogin",
                    data:{
          "username":username,"password":password,"flag":flag},
                    beforeSend:function(){
          
                        loadingIndex = layer.msg('登录中', {
          icon: 16});
                    },
                    success:function(result){
          
                        layer.close(loadingIndex);
                        if(result.success){
          
                            //后台验证用户的信息成功之后，跳转到index.jsp页面
                            window.location.href = "index";
                        }else{
          
                            layer.msg("用户的登录账号或密码不正确，请重新输入！", {
          time:2000, icon:2, shift:6}, function(){
          });
                        }
                    }
                });
            }
        </script>
    </body>
    </html>

**2.register.jsp**

<%@ page language="java" contentType="text/html; charset=UTF-8"
             pageEncoding="UTF-8"%>
    
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <title>用户注册</title>
        <link rel="stylesheet" href="./css/reg.css">
    
    </head>
    <body>
        <div class="reg">
            <div class="header">
                <h1>
                    <a href="./login">登录</a> <a href="./register">注册</a>
                </h1>
            </div>
            <form action="" method="post" id="userForm">
                <table>
                    <tr>
                        <td class="td1">用户名</td>
                        <td><input type="text" class="input1" name="username" id="username" placeholder="请输入用户名"></td>
                    </tr>
                    <tr>
                        <td class="td1">密码</td>
                        <td><input type="password" class="input1" name="password" id="password" placeholder="请输入密码"></td>
                    </tr>
                    <tr>
                        <td colspan="2">
                            <div class="btn-red">
                                <input type="button" value="注册" id="reg-btn" onclick="doRegister()">
                            </div>
                        </td>
                    </tr>
                </table>
            </form>
        </div>
    
        <script src="jquery/jquery-2.1.1.min.js"></script>
        <script src="layer/layer.js"></script>
    
        <script>
            //1.登录单击事件
            function doRegister(){
          
                //账号和密码的非空校验(使用jQuery做的id选择器)
                var username = $("#username").val();
                var password = $("#password").val();
                var pwdReg = /^(?![0-9]+$)(?![a-zA-Z]+$)[0-9A-Za-z]{8,16}$/;
    
                //表单元素的value取值不会为null，当为空时是空字符串
                if(username == "" || password == ""){
          
    
                    /*为了使弹出框的样式保持一致，不受浏览器的影响，可以使用组件layer
                    * layer.msg(arg1,arg2,arg3)
                    * arg1：提示信息
                    * arg2: time为弹出框持续的时间，单位为ms
                    *       icon为弹出框呈现的样式
                    *       shift为弹出框出现的样式
                    * arg3: 回调方法
                    * 具体细节可以参考layer文档
                    * */
                    layer.msg("用户注册账号或密码为空，请输入", {
          time:2000, icon:5, shift:6}, function(){
          });
                    return;
                }
    
                //验证密码是否符合要求
                if(!pwdReg.test(password)){
          
                    layer.msg("密码必须由数字和字母组成，且长度在8-16位之间，请重新输入", {
          time:2000, icon:5, shift:6}, function(){
          });
                    $("#password").reset();
                    return;
                }
    
                //提交表单
                var loadingIndex=null;
                $.ajax({
          
                    type:"POST",
                    url:"doAjaxRegister",
                    data:{
          "username":username,"password":password},
                    beforeSend:function(){
          
                        loadingIndex = layer.msg('注册中', {
          icon: 16});
                    },
                    success:function(result){
          
                        layer.close(loadingIndex);
                        if(result.success){
          
                            layer.msg("注册成功!", {
          time:2000, icon:2, shift:6}, function(){
          });
                            //后台验证用户注册成功之后，跳转到login.jsp页面
                            window.location.href = "login";
                        }else{
          
                            layer.msg("该用户名已经被注册，请重新填写！", {
          time:2000, icon:2, shift:6}, function(){
          });
                            //清除已经填写的用户信息
                            $("#userForm")[0].reset();
                        }
                    }
                });
            }
    
        </script>
    
    </body>
    </html>

### 五、完成前端与后台的交互 ###

后台的目录结构如下所示

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 9]  
**AjaxResult.java**

package com.test.bean;
    
    public class AjaxResult {
        
    
        //用于后台的逻辑判断
        private boolean success;
        //后台向前端返回的对象
        private Object data;
    
        public Object getData() {
        
            return data;
        }
    
        public void setData(Object data) {
        
            this.data = data;
        }
    
        public boolean isSuccess() {
        
            return success;
        }
    
        public void setSuccess(boolean success) {
        
            this.success = success;
        }
    
    }

**1.登录与注册功能**  
**(1)控制器类 DispatcherController.java，用于转发各种请求**

package com.test.controller;
    
    import com.test.bean.AjaxResult;
    import com.test.bean.User;
    import com.test.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    import javax.servlet.http.Cookie;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    @Controller
    public class DispatcherController {
        
    
        @Autowired
        private UserService userService;
    
        //1.跳转到登录页面
        @RequestMapping("login")
        public String login(){
        
            return "login";
        }
    
        //2.跳转到注册页面
        @RequestMapping("register")
        public String register(){
        
            return "register";
        }
    
        //2.登录成功后跳转到index.jsp页面
        @RequestMapping("index")
        public String index(){
        
            return "index";
        }
    
        //3.用Ajax完成登录操作，但不跳转页面
        @ResponseBody
        @RequestMapping("doAjaxLogin")
        public Object doAjaxLogin(User user, HttpSession session, HttpServletResponse response){
        
    
            //创建一个AjaxResult对象，用于保存各种
            AjaxResult ajaxResult = new AjaxResult();
    
            User dbUser = userService.queryForLogin(user);
    
            //登录成功
            if(dbUser != null){
        
                //将用户放入session中
                session.setAttribute("loginUser",dbUser.getUsername());
    
                //获取是否记住用户名单选框的状态
                if("true".equals(user.getFlag())){
        
                    // 完成记住用户名的功能:
                    Cookie cookie = new Cookie("username",user.getUsername());
                    //设置有效路径:
                    cookie.setPath("/ssmtest");
                    // 设置有效时间:
                    cookie.setMaxAge(60*60*24);// 保存24小时
                    // 将cookie回写到浏览器：
                    response.addCookie(cookie);
                }
    
                ajaxResult.setSuccess(true);
            }else{
        
                ajaxResult.setSuccess(false);
            }
    
            return ajaxResult;
        }
    
        //3.用Ajax完成注册操作，但不跳转页面
        @ResponseBody
        @RequestMapping("doAjaxRegister")
        public Object doAjaxRegister(User user){
        
    
            //创建一个AjaxResult对象，用于保存各种
            AjaxResult ajaxResult = new AjaxResult();
    
            User dbUser = userService.queryForLogin(user);
    
            if(dbUser != null){
        
                //该用户已经被注册
                ajaxResult.setSuccess(false);
            }else{
        
                try {
        
                    userService.insertUser(user);
    
                    ajaxResult.setSuccess(true);
                }catch (Exception e){
        
                    e.printStackTrace();
                    ajaxResult.setSuccess(false);
                }
            }
            return ajaxResult;
        }
    }

**(2).业务逻辑层(接口) UserService**

package com.test.service;
    
    import com.test.bean.User;
    
    public interface UserService {
        
    
        //查询登录用户
        User queryForLogin(User user);
    
        //注册用户
        void insertUser(User user);
    }

**(3).业务逻辑实现 UserServiceImpl**

package com.test.serviceImpl;
    
    import com.test.bean.User;
    import com.test.dao.UserDao;
    import com.test.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    @Service
    public class UserServiceImpl implements UserService {
        
    
        @Autowired
        private UserDao userDao;
    
        @Override
        public User queryForLogin(User user) {
        
            return userDao.queryForLogin(user);
        }
    
        @Override
        public void insertUser(User user) {
        
            userDao.insertUser(user);
        }
    }

**(4)数据访问层**

package com.test.dao;
    
    import com.test.bean.User;
    import org.apache.ibatis.annotations.Select;
    import org.springframework.stereotype.Repository;
    
    @Repository
    public interface UserDao {
        
    
        //由于该查询语句较为简单，所以可以直接在@Select注解中写SQL语句
        @Select("select * from t_user where username = #{username} and password = #{password}")
        User queryForLogin(User user);
          
       //sql语句在mapper-user.xml文件中编写
        void insertUser(User user);
    }

此时应该在mapper-user.xml文件中添加insertUser方法对应的SQL语句  
**mapper-user.xml**

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.test.dao.UserDao" >
    
        
        <insert id="insertUser">
            insert INTO t_user (username, password)
            values (#{username},#{password})
        </insert>
        
    </mapper>

此时进行测试  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 10]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzAwNDA0NA_size_16_color_FFFFFF_t_70 11]  
不出问题的话，注册应该也是没有什么问题的。

**2.使用拦截器阻止未登陆的用户访问index.jsp页面**  
可能有人会想到如果直接在浏览器中输入http://localhost:8080/ssmtest/index，那么能不能直接访问到index.jsp页面？如果在用户访问该页面之前不进行登陆信息验证的话，那么是可以直接访问到的，这显然是不安全的。所以这里可以使用SpringMVC的组件拦截器（具体相关内容可以参考我之前整理的[浅谈SpringMVC中的拦截器控件][SpringMVC]）  
**（1）添加拦截器类LoginInteceptor.java**

package com.test.web;
    
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    public class LoginInteceptor implements HandlerInterceptor{
        
    
        /*在拦截器拦截之前判断是否之后的操作
         * @return false：不再继续执行后面的操作
         *         true：继续执行后面的操作
         * */
        @Override
        public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        
            //判断当前的用户是否已经登录
            HttpSession session = httpServletRequest.getSession();
            String loginUser = (String)session.getAttribute("loginUser");
    
            //用户未登陆，跳转到登录页面
            if(loginUser == null){
        
                String path = session.getServletContext().getContextPath();
                httpServletResponse.sendRedirect(path + "/login");
                return false;
            }else{
        
                return true;
            }
    
        }
    
        //在拦截器拦截完毕之后进行的操作
        @Override
        public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        
    
        }
    
        //在完成视图渲染之后进行的操作
        @Override
        public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        
    
        }
    }

**（2）在springmvc-context.xml文件中配置该拦截器**

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:mvc="http://www.springframework.org/schema/mvc"
           xsi:schemaLocation="http://www.springframework.org/schema/mvc
           http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
            http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
            http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    
        
        <context:component-scan base-package="com.*" use-default-filters="false" >
            <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
        </context:component-scan>
    
    
        
        <mvc:default-servlet-handler/>
        
        <mvc:annotation-driven/>
    
    
        
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" >
            <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
            <property name="prefix" value="/WEB-INF/jsp/"/>
            <property name="suffix" value=".jsp"/>
        </bean>
    
        
        <mvc:interceptors>
            
            <mvc:interceptor>
                
                <mvc:mapping path="/**"/>
                
                <mvc:exclude-mapping path="/login"/>
                <mvc:exclude-mapping path="/doAjaxLogin"/>
                <mvc:exclude-mapping path="/register"/>
                <mvc:exclude-mapping path="/doAjaxRegister"/>
                <mvc:exclude-mapping path="/login"/>
                <mvc:exclude-mapping path="/css/**"/>
                <mvc:exclude-mapping path="/jquery/**"/>
                <mvc:exclude-mapping path="/layer/**"/>
                <bean class="com.test.web.LoginInteceptor"></bean>
            </mvc:interceptor>
        </mvc:interceptors>
    
    </beans>

**3.使用Cookie完成记住用户名的功能**  
**在CookieUtils .java中创建findCookie方法，便于寻找用户名**

package com.test.utils;
    
    import javax.servlet.http.Cookie;
    
    //在浏览器中回显用户名
    public class CookieUtils {
        
    
        public static Cookie findCookie(Cookie[] cookies , String name){
        
            if(cookies == null){
        
                // 说明客户端没有携带Cookie:
                return null;
            }else{
        
                // 说明客户端携带Cookie:
                for (Cookie cookie : cookies) {
        
                    if(name.equals(cookie.getName())){
        
                        return cookie;
                    }
                }
                return null;
            }
        }
    }

其余相关的操作在前面的代码已经给出

**4.防止用户多处登录**  
**(1).创建一个用户缓存类LoginCache.java，用于在session中保存用户的相关信息，以便于之后的验证**

package com.test.utils;
    
    import javax.servlet.http.HttpSession;
    import java.util.HashMap;
    import java.util.Map;
    
    public class LoginCache {
        
    
        //使用单例模式
        private LoginCache(){
        }
    
        private static LoginCache instance = new LoginCache();
    
        public static LoginCache getInstance(){
        
            return instance;
        }
    
        // key值：登录用户登录名，value值：登录用户sessionId
        private Map<String,String> loginUserSession = new HashMap<String,String>();
        //key值:登录用户sessionId,value值：登录用户session对象
        private Map<String,HttpSession> loginSession = new HashMap<String,HttpSession>();
    
        /**
         * 通过登录名获取对应登录用户的sessionId
         * @param username
         * @return
         */
        public String getSessionIdByUsername(String username){
        
            return loginUserSession.get(username);
        }
    
        /**
         * 通过sessionId获取对应的session对象
         * @param sessionId
         * @return
         */
        public HttpSession getSessionBySessionId(String sessionId){
        
            return loginSession.get(sessionId);
        }
    
        /**
         * 存储登录名与对应的登录sessionID至缓存对象
         * @param username
         * @param sessionId
         */
        public void setSessionIdByUserName(String username,String sessionId){
        
            loginUserSession.put(username, sessionId);
        }
    
        /**
         * 存储sessionId与对应的session对象至缓存对象
         * @param sessionId
         * @param session
         */
        public void setSessionBySessionId(String sessionId,HttpSession session){
        
            loginSession.put(sessionId, session);
        }
    
    }

**(2)创建LoginSessionListener类，用户监听用户属性在session中的变化**

package com.test.listener;
    
    import com.test.utils.LoginCache;
    
    import javax.servlet.http.HttpSession;
    import javax.servlet.http.HttpSessionAttributeListener;
    import javax.servlet.http.HttpSessionBindingEvent;
    
    public class LoginSessionListener implements HttpSessionAttributeListener{
        
    
        private static final String LOGINUSER="loginUser";
    
        @Override
        public void attributeAdded(HttpSessionBindingEvent httpSessionBindingEvent) {
        
            //获得session中添加的属性值的名称
            String attrName = httpSessionBindingEvent.getName();
    
            if(LOGINUSER.equals(attrName)){
        
                //获取添加的属性值，即用户登录名
                String attrValue = (String)httpSessionBindingEvent.getValue();
                //该次操作的session对象
                HttpSession session1 = httpSessionBindingEvent.getSession();
                //该次操作的session对象ID
                String sessionId = session1.getId();
                //从缓存对象里面，获得该用户登录名对应的sessionID值
                String sessionId2 = LoginCache.getInstance().getSessionIdByUsername(attrValue);
                //未获得结果，不需要清理前次登录用户会话信息
                if(null == sessionId2){
        
    
                }else{
        
                    HttpSession session2 = LoginCache.getInstance().getSessionBySessionId(sessionId2);//获取前次该用户登录对应的session对象
                    //清理前次登录用户会话存储信息，使得前次登录失效
                    session2.invalidate();
                }
    
                //完成该次登录用户登录名、sessionID，session对象的缓存对象存储
                LoginCache.getInstance().setSessionIdByUserName(attrValue, sessionId);
                LoginCache.getInstance().setSessionBySessionId(sessionId, session1);
            }
        }
    
        @Override
        public void attributeRemoved(HttpSessionBindingEvent httpSessionBindingEvent) {
        
    
        }
    
        @Override
        public void attributeReplaced(HttpSessionBindingEvent httpSessionBindingEvent) {
        
    
        }
    }

**(3)在web.xml文件中注册该监听器**

这样一来，若同一个用户在两处登录同一个账号时，那么前一个登录的用户信息会被清除，并且由拦截器拦截到用户信息在session中为空之后，直接跳转到login.jsp页面，这样便实现了同一个用户不能多处登录。  
**好啦！到这里为止，一个基于SSM框架的登录注册案例便完成了。一些必要的注释我已经在代码中给出，由于文字不能完全地还原整个开发过程，所以给出的代码顺序会存在一些前后台不同步的情况，不过给出的代码应该是完整的。如果大家发现了错误可以直接提出来哦~~**  
**该案例源码：[ssmtest][]  
提取码：86rm**

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[Link 1]: https://blog.csdn.net/qq_34377273/article/details/83183307
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[20190904191334806.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/77de029fab814430ae685433941e0051.png
[20190905232742813.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/57b93bda586d4ab19f880d975926d4aa.png
[20190905235327688.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/627764755ddb45b697a7448826cf41e9.png
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[20190905235919152.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/7ec78a0e979a494a949696461c0a572c.png
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[SpringMVC]: https://blog.csdn.net/weixin_43004044/article/details/98769819
[ssmtest]: https://pan.baidu.com/s/1vUyVhLqxm4xURdSEcK9ORA