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。
*/
@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