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