JAVA Filter\Interceptor\Aspect 对比

0、拦截顺序

Filter
        
Interceptor
        
ControllerAdvice
        
Aspect
        
Controller

 

一、过滤器 Filter

能够拿到原始http的请求和响应的信息

可是拿不到请求方法的信息   

package com.moon.web.filter;

import java.io.IOException;
import java.util.Date;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 * 能够拿到原始http的请求和响应的信息,可是拿不到请求方法的信息
 */
@Component
public class TimeFilter implements Filter {

	@Override
	public void destroy() {
		System.out.println("time filter destroy");
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		System.out.println("time filter start");
		long start = new Date().getTime();
		chain.doFilter(request, response);
		System.out.println("time filter 耗时:"+ (new Date().getTime() - start));
		System.out.println("time filter finish");
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
		System.out.println("time filter init");
	}

}

二、拦截器 interceptor

能够拿到原始http的请求和响应的信息

能够拿到请求方法的信息

可是拿不到调用方法的参数值信息

package com.moon.web.interceptor;

import java.util.Date;

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

import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

/**
 * 虽然加了 @Component 注解，可是并不会起做用
 * 还须要添加到spring boot的拦截器链上
 * 在 WebConfig 类上 extends WebMvcConfigurerAdapter 并实现下面的方法
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
		registry.addInterceptor(timeInterceptor);
    }
 *
 */
@Component
public class TimeInterceptor implements HandlerInterceptor {

    /**
     * 一、某个类的某个方法调用以前被调用
     *
     * Object handler 拿不到请求参数，参考源码 DispatcherServlet.java 962 行

     // 至关于调用这个方法 preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
     if (!mappedHandler.applyPreHandle(processedRequest, response)) {
        return;
     }

     // 参数的封装在这里完成 Actually invoke the handler.
     ModelAndView mv = ha.handle(processedRequest, response, mappedHandler.getHandler());

     *
     *
     * 返回 true 调用后面的方法；false 不会调用后面的方法
     */
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		System.out.println("一、preHandle");

		// 能够获取到具体的类名和方法名
		System.out.println(((HandlerMethod)handler).getBean().getClass().getName());
		System.out.println(((HandlerMethod)handler).getMethod().getName());
		
		request.setAttribute("startTime", new Date().getTime());
		return true;
	}

    /**
     * 二、某个类的某个方法调用以后被调用，若是出了异常将不会被调用
     */
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		System.out.println("二、postHandle");
		Long start = (Long) request.getAttribute("startTime");
		System.out.println("time interceptor 耗时:"+ (new Date().getTime() - start));

	}

    /**
     * 三、某个类的某个方法调用以后被调用，无论出不出异常都会被调用
     */
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		System.out.println("三、afterCompletion");
		Long start = (Long) request.getAttribute("startTime");
		System.out.println("time interceptor 耗时:"+ (new Date().getTime() - start));
		System.out.println("ex is "+ex);

	}

}

三、切片 aspect

能够拿到请求方法的信息，

能够拿到调用方法的参数值信息，

直接拿不到http的请求和响应的信息，能够经过下面RequestContextHolder对象拿到

ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
HttpServletRequest request = attributes.getRequest();

String requestParam = getReqParameter(request);
String requestMethod = request.getMethod();
String uri = request.getRequestURI();

spring aop 简介
切片（类）
        
切入点（注解）
a、在哪些方法上起做用
b、在何时起做用
        
加强（方法）
起做用时执行的业务逻辑

package com.moon.web.aspect;

import java.util.Date;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

/**
 *
 * @Aspect 须要加入依赖
     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-aop</artifactId>
     </dependency>
 *
 */
@Aspect
@Component
public class TimeAspect {

    /**
     * 定义了在何时起做用 Around
     * 在哪些方法上起做用 execution(* com.moon.web.controller.UserController.*(..))
     * 具体语法可参考
     * https://docs.spring.io/spring/docs/4.3.12.BUILD-SNAPSHOT/spring-framework-reference/htmlsingle/#aop-pointcuts
     * 搜关键字 Examples
     *
     * 优势：能拿到controller方法上参数的值
     *
     * @param pjp
     * @return
     * @throws Throwable
     */
	@Around("execution(* com.moon.web.controller.UserController.*(..))")
	public Object handleControllerMethod(ProceedingJoinPoint pjp) throws Throwable {
		
		System.out.println("time aspect start");

		// 获取调用方法的参数
		Object[] args = pjp.getArgs();
		for (Object arg : args) {
			System.out.println("arg is "+arg);
		}
		
		long start = new Date().getTime();
		
		Object object = pjp.proceed(); // 调用具体方法，获得返回的对象
		
		System.out.println("time aspect 耗时:"+ (new Date().getTime() - start));
		
		System.out.println("time aspect end");
		
		return object;
	}

}