SpringMVC拦截器

1.拦截器里面的方法，prehander是顺序执行，afterCompletion，postHandle逆序执行。

2.postHandler只有当本次拦截全部为true的时候才能执行。

3.如果url没有设置拦截器，则直接映射跳转，不经过拦截器。经过拦截器可以判断是否有账户登录进行true和false反馈。

工程网络



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_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>SpringMvc11</display-name>
<!-- The front controller of this Spring Web application, responsible for handling all application requests -->
<servlet>
<servlet-name>springDispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<!-- Map all requests to the DispatcherServlet for handling -->
<servlet-mapping>
<servlet-name>springDispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>

springmvc.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/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd 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-4.2.xsd"> 
<mvc:annotation-driven/>

<!-- 视图解析器 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/views/"></property>
<property name="suffix" value=".jsp"></property>
</bean>

<context:component-scan base-package="com.hellojava"></context:component-scan>

<!-- 拦截所有的请求 -->
<!---->
<mvc:interceptors>
<bean class="com.hellojava.tools.MyHandlerInterceptor"></bean>
<bean class="com.hellojava.tools.TestHandlerInceptor"></bean>
<bean class="com.hellojava.tools.HelloHandlerInterceptor"></bean>
</mvc:interceptors>

<!-- 拦截指定的 请求
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/success"/>
<mvc:exclude-mapping path="/index"/>
<bean class="com.hellojava.tools.MyHandlerInterceptor"></bean>
</mvc:interceptor>
</mvc:interceptors>
-->
</beans>

interceptor拦截器

package com.hellojava.tools;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

public class MyHandlerInterceptor implements HandlerInterceptor{

/**
* 目标方法之后，渲染视图ModelAndView之后
*/
public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
throws Exception {
System.out.println("afterCompletion");
}
/**
* 目标方法之后，渲染视图之前
*/
public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
throws Exception {
System.out.println("postHandle");
}
/**
* 目标方法之前
* return true 则调用目标方法和后续的拦截器
* return false 则不调用目标方法和后续的拦截器
*/
public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
System.out.println("preHandle");
return true;
}
}

contorller

package com.hellojava.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class TestController {
@RequestMapping("/success")
public String success(){
System.out.println("success view");
return "success";
}

@RequestMapping("/index")
public String index(){
System.out.println("index");
return "index";
}
}