SpringMVC学习笔记九:拦截器及拦截器的简单实用

SpringMVC中的interceptor拦截器是非常重要的,它的主要作用就是拦截指定的用户请求,并进行相应的预处理和后处理.

拦截时间点在"处理器映射器根据用户提交的请求映射出所要执行的处理器类,并且也找到了要执行该处理器类的处理器适配

器,在处理器适配器执行处理器之前"

项目目录树:

web.xml

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>

<!-- 注册字符集Filter -->
<filter>
    <filter-name>characterEncodingFiter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>GBK</param-value>
    </init-param>
    <init-param>
        <param-name>forceEncoding</param-name>
        <param-value>true</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>characterEncodingFiter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
  
<!-- 注册springMVC中央调度器 -->
<servlet>
    <servlet-name>springMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-mvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>springMVC</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

</web-app>

spring-mvc.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:mvc="http://www.springframework.org/schema/mvc"  
    xmlns:context="http://www.springframework.org/schema/context"  
    xsi:schemaLocation="  
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd  
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-4.0.xsd  
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-4.0.xsd">
    
    <!-- 扫描注解 -->
    <context:component-scan base-package="com.orange.controller" />    
    
    <!-- 注册拦截器 -->
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="com.orange.interceptor.myInterceptor"></bean>
        </mvc:interceptor>
        
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="com.orange.interceptor.myInterceptor2"></bean>
        </mvc:interceptor>
    </mvc:interceptors>
    
</beans>

控制器MyController.java

package com.orange.controller;

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

@Controller
@RequestMapping("/interceptor")
public class MyController {

    @RequestMapping("/interceptor")
    public String doInterceptor(){
        
        System.out.println("-------处理器MyController执行--------");
        
        return "/show.jsp";
    }
}

拦截器myInterceptor.java

package com.orange.interceptor;

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

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

public class myInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("--------myInterceptor.preHandle()------------");
        String p = request.getParameter("p");
        if(p != null){
            request.setAttribute("message", "验证生效!");
            request.getRequestDispatcher("/index.jsp").forward(request, response);
            return false;
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        System.out.println("--------myInterceptor.postHandle()------------");
        
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("--------myInterceptor.afterCompletion()------------");
        
    }

}

拦截器myInterceptor2.java

package com.orange.interceptor;

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

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

public class myInterceptor2 implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("--------myInterceptor2.preHandle()------------");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        System.out.println("--------myInterceptor2.postHandle()------------");
        
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("--------myInterceptor2.afterCompletion()------------");
        
    }

}

测试页面index.jsp

<%@ page language="java" contentType="text/html; charset=GBK"
    pageEncoding="GBK"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>    
<%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!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=GBK">
<base href="<%=basePath %>">
<title>Default Page</title>
</head>
<body>
<c:out value="${message }"></c:out>
<hr>
    <a href="interceptor/interceptor">测试</a>
    <a href="interceptor/interceptor?p=1">测试验证</a>
</body>
</html>

测试页面show.jsp

<%@ page language="java" contentType="text/html; charset=GBK"
    pageEncoding="GBK"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>    
<%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!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=GBK">
<base href="<%=basePath %>">
<title>Default Page</title>
</head>
<body>
    Show Page
</body>
</html>

测试结果

当正常测试时,拦截器中方法的执行顺序

拦截器执行顺序为:

测试拦截器简单实用,请求携带参数p时