子线程继承主线程的UUID

主线程的uuid是用MDC类put进去的

MDC.put("uuid", "xxxxxxxxxxxxxxxxxxxxxxxxx");

子线程继承主线程的UUID

package com.jushisi.thread;

import java.util.Map;

import org.slf4j.MDC;

import com.alibaba.fastjson.JSON;
import com.jushisi.framework.utils.LogWriter;

public class MyRunnable implements Runnable {

	private Runnable runnable;
    private Map map;
    
    public MyRunnable() {
    	
    }
    
    /**
     * 传入runnable类，并获取主线程中的所有参数（调用该构造器是父线程，所以这里的MDC.getXxxx获取到绑定在父线程的变量）
     * @param runnable
     */
    public MyRunnable(Runnable runnable) {
        this.runnable = runnable;
        this.map = MDC.getCopyOfContextMap();
    }
    
	@Override
	public void run() {
		// 可能是null，必须判断，追踪进代码可见null时会发生NPE
		LogWriter.info("MDC MAP:"+JSON.toJSONString(map));
        if (map != null) {
            MDC.setContextMap(map);
        }
        try {
            runnable.run();
        } finally {
            // 即使未执行setContextMap，这里可以clear不出错
            MDC.clear();
        }
	}

}