怎么aop中实现记录请求访问时间:用ThreadLocal

package com.example.demo.aop;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;
import java.util.logging.Logger;


/**
 * Create by szw on 2017/11/29 17:22
 */

/**
 * 切面
 */
@Aspect
@Component
public class WebLogAspect {
    private Logger logger = Logger.getLogger(String.valueOf(getClass()));
    ThreadLocal startTime = new ThreadLocal<>();
    /**
     * 切点表达式
     */
    @Pointcut("execution(public * com.example.demo.web..*.*(..))")
    public void webLog(){};

    /**
     * 前置通知
     */
    @Before("webLog()")
    public void doBefore(JoinPoint joinPoint)throws Throwable {
        /**
         * 接收到请求,记录请求内容
         */
        startTime.set(System.currentTimeMillis());
        ServletRequestAttributes attributes  = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        /**
         * 记录下请求内容
         */
        logger.info("URL:"+request.getRequestURL().toString());
        logger.info("HTTP_METHOD:" + request.getMethod());
        logger.info("IP:"+request.getRemoteAddr());
        logger.info("CLASS_METHOD:" + joinPoint.getSignature().getDeclaringTypeName() + "." + joinPoint.getSignature().getName());
        logger.info("ARGS:" + Arrays.toString(joinPoint.getArgs()));
        logger.info("SPEND TIME : " + (System.currentTimeMillis() - startTime.get()));
    }

    /**
     * 返回后通知
     * @param ret
     * @throws Throwable
     */
    @AfterReturning(returning = "ret",pointcut = "webLog()")
    public void doAfterReturning(Object ret) throws Throwable{
        /**
         * 处理完请求,记录返回内容
         */
        logger.info("RESPONSE:"+ret);
    }
}