Java 高并发 计算各个线程运行时间

  public class MyExecutor extends ThreadPoolExecutor {

   public MyExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue workQueue) {
       super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
       startTimes=new ConcurrentHashMap<>();
    }

            private ConcurrentHashMap startTimes;

             @Override
             protected void beforeExecute(Thread t, Runnable r) {

                 startTimes.put(String.valueOf(r.hashCode()), new Date());
             }

             @Override
             protected void afterExecute(Runnable r, Throwable t) {

                 Future result=(Future)r;
                 try {

                     Date startDate=startTimes.remove(String.valueOf(r.hashCode()));
                     Date finishDate=new Date();
                     long diff=finishDate.getTime()-startDate.getTime();
                     System.out.printf("MyExecutor: Duration: %d\n",diff);

                  } catch (InterruptedException | ExecutionException e) { e.printStackTrace();}
          }
}