SpringMVC学习笔记（十四）

1、SpringMVC拦截器

SpringMVC拦截器类似于Servlet开发的过滤器Filter，用于对处理器进行预处理和后处理。

2、简单实例

（1）项目结构

（2）HelloController.java

package cn.hwd.springmvc.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;@Controller@RequestMapping("/hello")public class HelloController {@RequestMapping("/index.action")      public String index() throws Exception {        return "index";      }}

（3）AHandlerInterceptor.java

package cn.hwd.springmvc.interceptor;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;/** * 定义拦截器并实现HandlerInterceptor接口 * @author huangwending * */public class AHandlerInterceptor implements HandlerInterceptor {/** * Handler方法完成之后执行，用于处理异常、日志等。 */@Overridepublic void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object handler, Exception ex)throws Exception {System.out.println("AHandlerInterceptor afterCompletion");}/** * 进入Handler方法之后、返回ModelAndView之前执行，用于处理模型数据、视图等。 */@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response,Object handler, ModelAndView modelAndView) throws Exception {System.out.println("AHandlerInterceptor postHandle");}/** * 进入Handler方法之前执行，用于身份认证、身份授权等。 * return false表示拦截，return true表示放行。 */@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception {System.out.println("AHandlerInterceptor preHandle");return true;}}

（4）BHandlerInterceptor.java

package cn.hwd.springmvc.interceptor;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;/** * 定义拦截器并实现HandlerInterceptor接口 * @author huangwending * */public class BHandlerInterceptor implements HandlerInterceptor {/** * Handler方法完成之后执行，用于处理异常、日志等。 */@Overridepublic void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object handler, Exception ex)throws Exception {System.out.println("BHandlerInterceptor afterCompletion");}/** * 进入Handler方法之后、返回ModelAndView之前执行，用于处理模型数据、视图等。 */@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response,Object handler, ModelAndView modelAndView) throws Exception {System.out.println("BHandlerInterceptor postHandle");}/** * 进入Handler方法之前执行，用于身份认证、身份授权等。 * return false表示拦截，return true表示放行。 */@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception {System.out.println("BHandlerInterceptor preHandle");return true;}}

（5）spring-servlet.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-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">        <context:component-scan base-package="cn.hwd.springmvc.controller" />    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix" value="/WEB-INF/page/" /><property name="suffix" value=".jsp" /></bean><!-- 配置拦截器 --><mvc:interceptors><!-- 多个拦截器顺序执行 --><mvc:interceptor><!-- /**表示拦截所有url（包括子url） --><mvc:mapping path="/**" /><bean class="cn.hwd.springmvc.interceptor.AHandlerInterceptor"></bean></mvc:interceptor><mvc:interceptor><mvc:mapping path="/**" /><bean class="cn.hwd.springmvc.interceptor.BHandlerInterceptor"></bean></mvc:interceptor></mvc:interceptors></beans>

（6）pom.xml

<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>  <groupId>cn.hwd</groupId>  <artifactId>SpringMVC42</artifactId>  <packaging>war</packaging>  <version>0.0.1-SNAPSHOT</version>  <name>SpringMVC42 Maven Webapp</name>  <url>http://maven.apache.org</url>  <build>    <finalName>SpringMVC42</finalName>    <plugins>      <plugin>        <groupId>org.apache.maven.plugins</groupId>        <artifactId>maven-compiler-plugin</artifactId>        <version>3.0</version>        <configuration>          <source>1.7</source>          <target>1.7</target>        </configuration>      </plugin>    </plugins>  </build>  <dependencies>  <dependency>  <groupId>javax.servlet</groupId>  <artifactId>servlet-api</artifactId>  <version>2.5</version>  </dependency>  <dependency>  <groupId>org.springframework</groupId>  <artifactId>spring-webmvc</artifactId>  <version>4.0.2.RELEASE</version></dependency>  </dependencies></project>

（7）index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"    pageEncoding="ISO-8859-1"%><!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=ISO-8859-1"><title>Insert title here</title></head><body></body></html>

（8）web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">  <display-name>Archetype Created Web Application</display-name>  <welcome-file-list>    <welcome-file>index.html</welcome-file>    <welcome-file>index.htm</welcome-file>    <welcome-file>index.jsp</welcome-file>    <welcome-file>default.html</welcome-file>    <welcome-file>default.htm</welcome-file>    <welcome-file>default.jsp</welcome-file>  </welcome-file-list>  <servlet>    <servlet-name>spring</servlet-name>    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>    <init-param>      <param-name>contextConfigLocation</param-name>      <param-value>classpath:spring-servlet.xml</param-value>    </init-param>  </servlet>  <servlet-mapping>    <servlet-name>spring</servlet-name>    <url-pattern>*.action</url-pattern>  </servlet-mapping></web-app>

（9）测试

场景一：A拦截器、B拦截器都放行

控制台输出

AHandlerInterceptor preHandleBHandlerInterceptor preHandleBHandlerInterceptor postHandleAHandlerInterceptor postHandleBHandlerInterceptor afterCompletionAHandlerInterceptor afterCompletion

场景二：A拦截器放行，B拦截器不放行

控制台输出

AHandlerInterceptor preHandleBHandlerInterceptor preHandleAHandlerInterceptor afterCompletion

场景三：A拦截器不放行，B拦截器放行

控制台输出

AHandlerInterceptor preHandle

场景四：A拦截器不放行，B拦截器不放行

控制台输出

AHandlerInterceptor preHandle