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  • 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

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  • 原文地址:https://www.cnblogs.com/djoker/p/6619054.html
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