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。 */ @Override public 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。 */ @Override public 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。 */ @Override public 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。 */ @Override public 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。 */ @Override public 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。 */ @Override public 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 preHandle BHandlerInterceptor preHandle BHandlerInterceptor postHandle AHandlerInterceptor postHandle BHandlerInterceptor afterCompletion AHandlerInterceptor afterCompletion场景二：A拦截器放行，B拦截器不放行
控制台输出
AHandlerInterceptor preHandle BHandlerInterceptor preHandle AHandlerInterceptor 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