验证用户是否登录 (认证用户)

实现思路

  1. 有一个登陆页面，需要写一个controller访问页面。
  2. 登陆页面有一提交表单的动作。需要在controller中处理。判断用户名密码是否正确。如果正确，向session中写入用户信息。返回登陆成功。
  3. 拦截用户请求，判断用户是否登陆。如果用户已经登陆。放行， 如果用户未登陆，跳转到登陆页面

测试：

（1）创建一个jsp包，创建main.jsp和login.jsp  

 login.jsp

 main.jsp

 

（2）编写一个登陆页面，一个主界面         login.jsp和main.jsp

login.jsp

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

<%--在web-inf下面的页面或者资源，只能通过controller，或者servlet进行访问--%>
<h1>登录页面</h1>

<form action="${pageContext.request.contextPath}/user/login" method="post">
    用户名：<input type="text" name="username"/>
    密码：<input type="text" name="password"/>
    <input type="submit" value="提交"/>
</form>

</body>
</html>

 

main.jsp（后续需要添加注销操作）

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

</body>
</html>

 

（3）编写一个Controller处理请求

package com.gt.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class LoginController {

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

    @RequestMapping("/goLogin")
    public String login() {
//        跳转视图--登录页面
        return "login";
    }


    @RequestMapping("/login")
    public String login(HttpSession session, String username, String password, Model model) {
        System.out.println("login==>" + username);
//        把用户的信息存在session中：
        session.setAttribute("userLoginInfo", username);
        model.addAttribute("username", username);
//        登录成功后跳转到主页面
        return "main";
    }

    @RequestMapping("/goOut")
    public String goOut(HttpSession session) {
//          移除（注销）
        session.removeAttribute("userLoginInfo");
        return "main";
    }
}

 

（4）因为在LoginController里面编写了移除注销所以在main里面需要添加注销操作 

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

<span>${username}</span>

<p>
    <a href="${pageContext.request.contextPath}/user/goOut">注销</a>
</p>

</body>
</html>

 

（5）编写用户登录拦截器

package com.gt.config;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.HandlerInterceptor;

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

@Controller
@RequestMapping("/user")
public class LoginInterceptor implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception{

        HttpSession session = request.getSession();
//        放行：判断什么情况下登录

//        登录页面也会放行
        if (request.getRequestURI().contains("goLogin")){
            return true;
        }

//       说明我在提交登录
        if (request.getRequestURI().contains("login")){
            return true;
        }

//        第一次登录，也是没有session的：
        if (session.getAttribute("userLoginInfo")!=null){
            return true;
        }

//        判断什么情况下没有登录
        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
        return false;
    }

}

 

（6）在Springmvc的配置文件中注册拦截器

    <!--    拦截器配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--            包括这个包请求下面的所有请求-->
            <mvc:mapping path="/**/"/>
            <bean class="com.gt.config.MyInterceptor"/>
        </mvc:interceptor>

        <mvc:interceptor>
            <!--            包括这个包请求下面的所有请求-->
            <mvc:mapping path="/user/**/"/>
            <bean class="com.gt.config.LoginInterceptor"/>
        </mvc:interceptor>

    </mvc:interceptors>

（7）重启tocat，测试

 

点击登录页面或者是首页，现在就只会跳转到登录页面 

 

 

 输入用户名密码，就能进去首页

 

 

点击注销就能返回登录页面

 

 

项目总代码

 

 LoginInterceptor：

package com.gt.config;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class LoginInterceptor implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception{

        HttpSession session = request.getSession();
//        放行：判断什么情况下登录

//        登录页面也会放行
        if (request.getRequestURI().contains("goLogin")){
            return true;
        }

//       说明我在提交登录
        if (request.getRequestURI().contains("login")){
            return true;
        }

//        第一次登录，也是没有session的：
        if (session.getAttribute("userLoginInfo")!=null){
            return true;
        }

//        判断什么情况下没有登录
        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
        return false;
    }

}

 MyInterceptor

package com.gt.config;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

public class MyInterceptor implements HandlerInterceptor {

    //    return true;执行下一个拦截器，放行
//    return false;不执行下一个拦截器
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("======处理前=========");
        return true;
    }

    拦截日志
//    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
//        System.out.println("=======处理后==========");
//    }
//
//    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
//        System.out.println("==========清理=========");
//    }
}

LoginController

package com.gt.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class LoginController {

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

    @RequestMapping("/goLogin")
    public String login() {
//        跳转视图--登录页面
        return "login";
    }


    @RequestMapping("/login")
    public String login(HttpSession session, String username, String password, Model model) {
        System.out.println("login==>" + username);
//        把用户的信息存在session中：
        session.setAttribute("userLoginInfo", username);
        model.addAttribute("username", username);
//        登录成功后跳转到主页面
        return "main";
    }

    @RequestMapping("/goOut")
    public String goOut(HttpSession session) {
//          移除（注销）
        session.removeAttribute("userLoginInfo");
        return "main";
    }
}

TestController

package com.gt.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {

    @GetMapping("/t1")
    public String test() {
        System.out.println("TestController==》test()执行了");
        return "OK";
    }
}

applicationContext.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:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       https://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!-- 自动扫描指定的包，下面所有注解类交给IOC容器管理 -->
    <context:component-scan base-package="com.gt.controller"/>
    <!--    静态资源过滤-->
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>

    <!--    乱码问题-->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          id="internalResourceViewResolver">
        <!-- 前缀 -->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!-- 后缀 -->
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--    拦截器配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--            包括这个包请求下面的所有请求-->
            <mvc:mapping path="/**/"/>
            <bean class="com.gt.config.MyInterceptor"/>
        </mvc:interceptor>

        <mvc:interceptor>
            <!--            包括这个包请求下面的所有请求-->
            <mvc:mapping path="/user/**/"/>
            <bean class="com.gt.config.LoginInterceptor"/>
        </mvc:interceptor>

    </mvc:interceptors>



</beans>

login.jsp

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

<%--在web-inf下面的页面或者资源，只能通过controller，或者servlet进行访问--%>
<h1>登录页面</h1>

<form action="${pageContext.request.contextPath}/user/login" method="post">
    用户名：<input type="text" name="username"/>
    密码：<input type="text" name="password"/>
    <input type="submit" value="提交"/>
</form>

</body>
</html>

main.jsp

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

<span>${username}</span>

<p>
    <a href="${pageContext.request.contextPath}/user/goOut">注销</a>
</p>

</body>
</html>

web.xml

<?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:applicationContext.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>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>


</web-app>

index.jsp 

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

<h1><a href="${pageContext.request.contextPath}/user/goLogin">登录页面</a></h1>
<h1><a href="${pageContext.request.contextPath}/user/main">首页</a></h1>


</body>
</html>

pom（项目自己）

<?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">
    <parent>
        <artifactId>SpringMVC</artifactId>
        <groupId>com.gt</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springmvc-07-intercepter</artifactId>


</project>

pom（总项目的）

<?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.gt</groupId>
    <artifactId>SpringMVC</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>springmvc-01-serlvet</module>
        <module>springmvc-02-hellomvc</module>
        <module>springmvc-03-annotation</module>
        <module>springmvc-04-controller</module>
        <module>springmvc-05-json</module>
        <module>springmvc-06-ajax</module>
        <module>springmvc-07-intercepter</module>


    </modules>

    <!--    导入依赖-->
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>


</project>

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