一、新建一个maven工程（不会建的小伙伴可以参考Idea引入maven工程依赖(保姆级)-CSDN博客），工程目录如图

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js文件可以上up网盘提取

链接：https://pan.baidu.com/s/1yOFtiZBWGJY64fa2tM9CYg?pwd=5555 
提取码：5555

二、配置pom.xml文件

<?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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.zl</groupId>
  <artifactId>project01</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>project01 Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <!--Jackson转换核心包依赖-->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.9.2</version>
    </dependency>
    <!--Jackson转换的数据绑定包依赖-->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.2</version>
    </dependency>
    <!--Jackson JSON转换注解包-->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>2.9.0</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.26</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.3</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>project01</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

三、配置web.xml文件

<?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_4_0.xsd"
         version="4.0">

  <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:springMVC.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>

  <!-- 配置编码过滤器 -->
  <filter>
    <filter-name>CharacterEncodingFilter</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>
  </filter>
  <filter-mapping>
    <filter-name>CharacterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

四、配置springMVC.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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
                 http://www.springframework.org/schema/mvc
                  http://www.springframework.org/schema/mvc/spring-mvc.xsd
                  http://www.springframework.org/schema/context
               http://www.springframework.org/schema/context/spring-context.xsd">
    <!-- 配置创建 spring 容器要扫描的包 -->
    <context:component-scan base-package="com.zl.controller"/>
    <!-- 配置视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <mvc:annotation-driven />
    <mvc:default-servlet-handler></mvc:default-servlet-handler>

</beans>

五、编写LoginController.java类

package com.zl.controller;

import com.zl.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;


import javax.servlet.http.HttpSession;
import java.util.HashMap;
import java.util.Map;

@Controller
public class LoginController {

    //主页
    @RequestMapping("/main")
    public String main(){
        return "main";
    }

    //登录页
    @RequestMapping("/ajaxlogin")
    public String hello(){
        return "Ajax_login";
    }


    /**
     * Ajax --- 登录验证
     */
    @RequestMapping("/loginAjax")
    @ResponseBody
    public String loginAjax(User user, Model model, HttpSession session){
        Map<String,String> resultMap = new HashMap<>();

        String username = user.getUsername();
        String password = user.getPassword();

        if ( null!= username && username.equals("user01")
                &&  null!= password && password.equals("123456")
        ){
            session.setAttribute("USER_SESSION",user);
            return "main";
        }
        model.addAttribute("msg","用户名或密码错误！");

        return   "error";
    }

}

六、编写LoginInterceptor.java类

package com.zl.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response
            , Object handler) throws Exception {
        HttpSession session = request.getSession();
        if (null!= session.getAttribute("USER_SESSION") ){
            return true;
        }

        request.getRequestDispatcher("/WEB-INF/pages/Ajax_login.jsp").forward(request,response);

        return false;
    }
}

七、Ajax_login.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
    <link rel="stylesheet" href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.4.1/css/bootstrap.min.css">
    <script type="text/javascript"
            src="${pageContext.request.contextPath }/js/jquery-3.6.0.js"></script>
</head>
<body>
<div>
    <div style="margin: 100px auto;">


        <div style="width: 600px">
            <h3>Ajax登录</h3>
            <div style="color: red">${msg}</div>
            用户名： <input id="username" type="text" name="username" value=""> <br><br>
            密码： <input id="password" type="password" name="password" value=""> <br><br>
            <button οnclick="login()">提交登录</button>
        </div>
    </div>

</div>


<hr/>
<br><br><br><br>



<script type="text/javascript">
    function login() {
        var username = $("#username").val();
        var password = $("#password").val();

        $.ajax({
            url: "${pageContext.request.contextPath }/loginAjax",
            type: "post",
            data: {username: username, password: password},
            success: function (response) {
                console.log(response)

                if (response=="main"){
                    window.location.href="http://localhost:8080/project01_war_exploded/main";
                }else {
                    alert("用户名或密码错误！")
                }

            }
        });
    }
</script>




</body>
</html>

注意更改自己tomcat的访问路径

八、编写main.jsp和error.jsp文件

main.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h1>主页</h1>

<h1>当前用户：${USER_SESSION.username}</h1><br><br>

</body>
</html>

error.jsp:

<%--
  Created by IntelliJ IDEA.
  User: 86158
  Date: 2024/4/4
  Time: 23:07
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
...error
</body>
</html>

九、配置tomcat（不会配置的小伙伴可参考Idea添加tomcat-CSDN博客），直接启动

启动成功

这样就成功啦！小伙伴们赶紧run起来吧！欢迎留言和私信up哦！制作不易，给个赞吧！嘻嘻