SpringMvc实现简单的拦截器代码与讲解
1.Springmvc需要的jar文件,其中部分为json操作jar(暂时未用)
2.登录界面,简单的jsp代码,模拟登录所需数据
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>login.jsp</title> </head> <body> <center> <form action="login.action" method="post"> <span>用户名:</span><input type="text" name="name"/><br> <span>密码:</span><input type="password" name="password"/> <input type="submit" value="提交"/> </form> </center> </body> </html>
3.登录拦截器控制设置,拦截action的登录请求以为的action,根据session中是否有user用户判断是否登录。(拦截器权限问题会在以后的博客中写到)
package com.ytk.controller; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; import com.ytk.util.Constants; public class LoginInterceptor implements HandlerInterceptor { @Override public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception { } @Override public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3) throws Exception { } @Override public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception { if(arg0.getRequestURI().indexOf("login.action")>0) { return true; } System.out.println(arg0.getSession().getAttribute(Constants.USER_CONTEXT)+"<<<<<<<<"); if(arg0.getSession().getAttribute(Constants.USER_CONTEXT)!=null) { return true; } arg1.sendRedirect("/index.jsp"); return false; } }
4.Spring 控制跳转,业务处理登录请求,登录action,退出action以及其业务逻辑处理
package com.ytk.controller; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import com.ytk.entity.User; @Controller public class LoginController extends BaseController { @RequestMapping("/login.action") public String login(HttpServletRequest request,User user,Model model) { setSessionUser(request, user); System.out.println("username:"+user.getName()); System.out.println("password:"+user.getPassword()); model.addAttribute("name", user); return "success"; } @RequestMapping("/logout.action") public String logout(HttpServletRequest request,HttpServletResponse response) { User user=getSessionUser(request); System.out.println(user.getName()); System.err.println(user.getPassword()); setSessionUser(request, null); return "logout"; } }
5.login登录成功之后界面以及登出请求处理
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>hello</title> </head> <body> 您好!${user.name }; <a href="logout.action">退出</a> success.jsp <c:if test="${not empty user }"> ${user.password } </c:if> </body> </html>
6.登出请求,首先触发拦截器处理。判断用户是否登录。并作出相应处理。然后进入4的logout.action方法
7.保存用户的session域设置,也是拦截器判断是否拦截的条件
package com.ytk.controller; import javax.servlet.http.HttpServletRequest; import com.ytk.entity.User; import com.ytk.util.Constants; public class BaseController { public void setSessionUser(HttpServletRequest request,User user) { request.getSession().setAttribute(Constants.USER_CONTEXT, user); } public User getSessionUser(HttpServletRequest request) { return (User)request.getSession().getAttribute(Constants.USER_CONTEXT); } }
8.用户entity文件
package com.ytk.entity; public class User { public User(){} private String name; private String password; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
package com.ytk.util; public class Constants { //用户域 public final static String USER_CONTEXT="user_context"; }
9.文件配置springmvc.xml,spring.xml以及web.xml文件配置
(1)spring.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:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> </beans>
(2)springmvc.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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/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-4.3.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd"> <context:component-scan base-package="com.ytk.controller"></context:component-scan> <mvc:annotation-driven/> <mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/*"/> <bean class="com.ytk.controller.LoginInterceptor"/> </mvc:interceptor> </mvc:interceptors> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/views/"/> <property name="suffix" value=".jsp"/> </bean> </beans>
(3)web.xml文件
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1"> <display-name>Springmvc</display-name> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring.xml</param-value> </context-param> <!-- sprigmvc注册核心拦截器 --> <servlet> <servlet-name>dispatcherServlet</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> </servlet> <servlet-mapping> <servlet-name>dispatcherServlet</servlet-name> <url-pattern>*.action</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>dispatcherServlet</servlet-name> <url-pattern>/user/**</url-pattern> </servlet-mapping> <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> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>10.文件目录结构