04点睛Spring MVC 4.1-拦截器

转发地址：https://www.iteye.com/blog/wiselyman-2214292

4.1 拦截器

拦截器实现了对每一个请求处理之前和之后进行相关的处理,类似于Servlet的filter;
可以实现HandlerInterceptor接口或者继承HandlerInterceptorAdapter类;
继承HandlerInterceptorAdapter类,因为使用接口要实现接口的所有方法;

4.2 示例

新建拦截器

package com.wisely.interceptors;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Service;

import org.springframework.web.servlet.ModelAndView;

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public class DemoInteceptor extends HandlerInterceptorAdapter {

    @Override

    public boolean preHandle(HttpServletRequest request,

            HttpServletResponse response, Object handler) throws Exception {

        System.out.println("request开始前");

        long startTime = System.currentTimeMillis();

        request.setAttribute("startTime", startTime);

        return true;

    }

    @Override

    public void postHandle(HttpServletRequest request,

            HttpServletResponse response, Object handler,

            ModelAndView modelAndView) throws Exception {

        System.out.println("request结束后");

        long startTime = (Long) request.getAttribute("startTime");

        request.removeAttribute("startTime");

        long endTime = System.currentTimeMillis();

        request.setAttribute("handlingTime", endTime - startTime);

    }

}

修改配置,注册拦截器

package com.wisely;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.ComponentScan;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.servlet.config.annotation.EnableWebMvc;

import org.springframework.web.servlet.config.annotation.InterceptorRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import org.springframework.web.servlet.view.JstlView;

import org.springframework.web.servlet.view.UrlBasedViewResolver;

import com.wisely.interceptors.DemoInteceptor;

@Configuration

@ComponentScan("com.wisely")

@EnableWebMvc

public class DemoMVCConfig extends WebMvcConfigurerAdapter {

    @Bean

    public UrlBasedViewResolver viewResolver(){

        UrlBasedViewResolver resolver = new UrlBasedViewResolver();

        resolver.setPrefix("/WEB-INF/views/");

        resolver.setSuffix(".jsp");

        resolver.setViewClass(JstlView.class);

        return resolver;

    }

    //注册拦截器

    @Override

    public void addInterceptors(InterceptorRegistry registry) {

    registry.addInterceptor(demoInteceptor());

    }

    //自定义拦截器

    @Bean

    public DemoInteceptor demoInteceptor(){

        return new DemoInteceptor();

    }

}

在index.jsp添加代码接受拦截器里放置的handlingTime

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!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=UTF-8">

<title>Insert title here</title>

</head>

<body>

index.jsp  is here

value from inteceptor 处理耗时:${handlingTime}ms

</body>

</html>

输出结果

巴特西

04点睛Spring MVC 4.1-拦截器

转发地址：https://www.iteye.com/blog/wiselyman-2214292

4.1 拦截器

4.2 示例

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