1.创建普通Maven项目后，添加web框架
2.配置web.xml配置文件，改为最新的4.0版本
<?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"> </web-app>
3.在web.xml配置注册DispatcherServlet
<!--1.注册DispatcherServlet--> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!--关联一个springmvc的配置文件:【servlet-name】-servlet.xml--> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc-servlet.xml</param-value> </init-param> <!--启动级别-1--> <load-on-startup>1</load-on-startup> </servlet> <!--/ 匹配所有的请求；（不包括.jsp）--> <!--/* 匹配所有的请求；（包括.jsp）--> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping>
4.配置springmvc-servlet.xml配置文件,名称：springmvc-servlet.xml,说明，这里的名称要求是按照官方来的。
加入jackson统一乱码解决，这是SpringMVC自带的！
<?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"> <context:component-scan base-package="com.shan.controller"/> <mvc:default-servlet-handler /> <!--jackson统一乱码解决--> <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> </beans>
5.编写Controller处理请求
import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; @Controller @RequestMapping("/user") public class UserController { //跳转到登陆页面 @RequestMapping("/jumplogin") public String jumpLogin() throws Exception { return "login"; } //跳转到成功页面 @RequestMapping("/jumpSuccess") public String jumpSuccess() throws Exception { return "main"; } //登陆提交 @RequestMapping("/login") public String login(HttpServletRequest request, HttpServletResponse response) throws Exception { // 向session记录用户身份信息 HttpSession session = request.getSession(); String username = request.getParameter("username"); System.out.println("接收前端用户名="+username); session.setAttribute("user", username); if (username.equals("")){ request.setAttribute("userinfo","用户名不能为空！"); return "/login"; //更加方便 //request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response); //也可以 } return "main"; } //退出登陆 @RequestMapping("logout") public String logout(HttpSession session) throws Exception { // session 过期 session.invalidate(); return "login"; } }
6.编写一个登陆页面 login.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>login</title> </head> <h1>登录页面</h1> <hr> <body> <form action="${pageContext.request.contextPath}/user/login"> 用户名：<input type="text" name="username"> <br> 密码：<input type="password" name="pwd"> <br> <input type="submit" value="提交"> </form> </body> </html>
7.编写一个登陆成功的页面 success.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <h1>登录成功页面</h1> <hr> ${user} <a href="${pageContext.request.contextPath}/user/logout">注销</a> </body> </html>
8.在 index 页面上测试跳转！启动Tomcat 测试，未登录也可以进入主页！
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>$Title$</title> </head> <body> <h1>首页</h1> <hr> <%--登录--%> <a href="${pageContext.request.contextPath}/user/jumplogin">登录</a> <a href="${pageContext.request.contextPath}/user/jumpSuccess">成功页面</a> </body> </html>
9.编写用户登录拦截器
package com.shan.interceptor; 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; import java.io.IOException; public class UserInterceptor implements HandlerInterceptor { public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws ServletException, IOException { // 如果是登陆页面则放行 System.out.println("uri: " + request.getRequestURI()); if (request.getRequestURI().contains("login")) { return true; } HttpSession session = request.getSession(); // 如果用户已登陆也放行 if(session.getAttribute("user") != null) { return true; } // 用户没有登陆跳转到登陆页面 request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response); return false; } }
10.在Springmvc的配置文件中注册拦截器
<mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/**"/> <bean id="loginInterceptor" class="com.shan.interceptor.UserInterceptor"/> </mvc:interceptor> </mvc:interceptors>
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