JAVA Filter\Interceptor\Aspect 對比

0、攔截順序

Filter
        
Interceptor
        
ControllerAdvice
        
Aspect
        
Controller

 

一、過濾器 Filter

能夠拿到原始http的請求和響應的信息

可是拿不到請求方法的信息   

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;

/**
 * 能夠拿到原始http的請求和響應的信息,可是拿不到請求方法的信息
 */
@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 耗時:"+ (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、攔截器 interceptor

能夠拿到原始http的請求和響應的信息

能夠拿到請求方法的信息

可是拿不到調用方法的參數值信息

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;

/**
 * 雖然加了 @Component 註解，可是並不會起做用
 * 還須要添加到spring boot的攔截器鏈上
 * 在 WebConfig 類上 extends WebMvcConfigurerAdapter 並實現下面的方法
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
		registry.addInterceptor(timeInterceptor);
    }
 *
 */
@Component
public class TimeInterceptor implements HandlerInterceptor {

    /**
     * 一、某個類的某個方法調用以前被調用
     *
     * Object handler 拿不到請求參數，參考源碼 DispatcherServlet.java 962 行

     // 至關於調用這個方法 preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
     if (!mappedHandler.applyPreHandle(processedRequest, response)) {
        return;
     }

     // 參數的封裝在這裏完成 Actually invoke the handler.
     ModelAndView mv = ha.handle(processedRequest, response, mappedHandler.getHandler());

     *
     *
     * 返回 true 調用後面的方法；false 不會調用後面的方法
     */
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		System.out.println("一、preHandle");

		// 能夠獲取到具體的類名和方法名
		System.out.println(((HandlerMethod)handler).getBean().getClass().getName());
		System.out.println(((HandlerMethod)handler).getMethod().getName());
		
		request.setAttribute("startTime", new Date().getTime());
		return true;
	}

    /**
     * 二、某個類的某個方法調用以後被調用，若是出了異常將不會被調用
     */
	@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 耗時:"+ (new Date().getTime() - start));

	}

    /**
     * 三、某個類的某個方法調用以後被調用，無論出不出異常都會被調用
     */
	@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 耗時:"+ (new Date().getTime() - start));
		System.out.println("ex is "+ex);

	}

}

三、切片 aspect

能夠拿到請求方法的信息，

能夠拿到調用方法的參數值信息，

直接拿不到http的請求和響應的信息，能夠經過下面RequestContextHolder對象拿到

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

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

spring aop 簡介
切片（類）
        
切入點（註解）
a、在哪些方法上起做用
b、在何時起做用
        
加強（方法）
起做用時執行的業務邏輯

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

    /**
     * 定義了在何時起做用 Around
     * 在哪些方法上起做用 execution(* com.moon.web.controller.UserController.*(..))
     * 具體語法可參考
     * https://docs.spring.io/spring/docs/4.3.12.BUILD-SNAPSHOT/spring-framework-reference/htmlsingle/#aop-pointcuts
     * 搜關鍵字 Examples
     *
     * 優勢：能拿到controller方法上參數的值
     *
     * @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");

		// 獲取調用方法的參數
		Object[] args = pjp.getArgs();
		for (Object arg : args) {
			System.out.println("arg is "+arg);
		}
		
		long start = new Date().getTime();
		
		Object object = pjp.proceed(); // 調用具體方法，獲得返回的對象
		
		System.out.println("time aspect 耗時:"+ (new Date().getTime() - start));
		
		System.out.println("time aspect end");
		
		return object;
	}

}