spring boot之spring mvc常用配置--拦截器配置(4)

2.拦截器配置
拦截器Interceptor实现对每一个请求处理前后进行相关的业务处理。类似于Servlet的Filter。
第一种方式：可以让普通的bean实现HandlerInterceptor接口或者继承HandlerInterceptorAdapter类来实现自定义拦截器。
①继承HandlerInterceptorAdapter类来实现自定义拦截器

重写preHandle：在请求发生前执行、postHandle在请求完后执行。

package com.boot.springmvc.interceptor;

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

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

public class DemoInterceptor extends HandlerInterceptorAdapter {//1

	@Override
	public boolean preHandle(HttpServletRequest request, //2
			HttpServletResponse response, Object handler) throws Exception {
		long startTime = System.currentTimeMillis();
		request.setAttribute("startTime", startTime);
		return true;
	}

	@Override
	public void postHandle(HttpServletRequest request, //3
			HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		long startTime = (Long) request.getAttribute("startTime");
		request.removeAttribute("startTime");
		long endTime = System.currentTimeMillis();
		System.out.println("本次请求处理时间为:" + new Long(endTime - startTime)+"ms");
		request.setAttribute("handlingTime", endTime - startTime);
	}

}

②配置拦截器的bean，重写addInterceptors

package com.boot.springmvc;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

import com.boot.springmvc.interceptor.DemoInterceptor;

/**
 * 	@Bean
	public InternalResourceViewResolver viewResolver();
 * 注入InternalResourceViewResolver类：
 * 说明：springmvc下有一个接口叫ViewResolver，(我们的viewResolver都实现该接口)，实现这个接口要重写
 * resolverName(),这个方法的返回值接口View，而view的职责就是使用model、request、response对象，并
 * 渲染视图(不一定是html、可能是json、xml、pdf等)给浏览器 。
 *
 */
@Configuration
@EnableWebMvc // 1开启默认配置
@EnableScheduling
@ComponentScan("com.boot.springmvc")
public class MyMvcConfig extends WebMvcConfigurerAdapter{//2
	//viewResolver
	@Bean
	public InternalResourceViewResolver viewResolver() {
		InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
		//viewResolver.setPrefix("/WEB-INF/classes/views/");//打war后默认编译的路径
		viewResolver.setPrefix("/WEB-INF/views/");//使用tomcat7:run插件后要放的位置
		viewResolver.setSuffix(".jsp");
		viewResolver.setViewClass(JstlView.class);
		return viewResolver;
	}
	//静态资源映射
	@Override
	public void addResourceHandlers(ResourceHandlerRegistry registry) {
		registry.addResourceHandler("/assets/**").addResourceLocations("classpath:/assets/");
	}// 3
	
	//拦截器
	@Bean
	// 1
	public DemoInterceptor demoInterceptor() {
		return new DemoInterceptor();
	}

	@Override
	public void addInterceptors(InterceptorRegistry registry) {// 2
		registry.addInterceptor(demoInterceptor());
	}
	
	
}

发起请求

处理结果