java - 如何访问自定义线程池执行器方法中的线程对象？

Question

我想访问自定义线程池执行器中可运行对象内的数据。如果我尝试在执行之前/之后访问方法，我会收到类转换异常。我该如何解决这种情况。

public class MyThread implements Runnable 
{
  String key;

  public void run(){ /* Do something */}  
}

public class MyExecutor extends ThreadPoolExecutor
{

  @Override
  protected void beforeExecute(Thread paramThread, Runnable paramRunnable)
  {
             MyThread mt = (mt)paramRunnable; 

  }

  @Override
  protected void afterExecute(Runnable paramRunnable, Throwable paramThrowable) 
 {
       MyThread mt = (mt)paramRunnable; 
    /* Need to access "key" inside MyThread */    
 }

Answer 1

如果得到 ClassCastException 这意味着您将不是 MyThread 或 MyThread 子类的 Thread 实现也传递到 MyExecutor 中。因此，为了修复它，您只需在转换之前执行 instanceof 检查。

public class MyExecutor extends ThreadPoolExecutor
{

  @Override
  protected void beforeExecute(Thread paramThread, Runnable paramRunnable)
  {
         if(paramRunnable instanceof MyThread) {
             MyThread mt = (MyThread)paramRunnable; 
         }

  }

  @Override
  protected void afterExecute(Runnable paramRunnable, Throwable paramThrowable) 
 {
       if(paramRunnable instanceof MyThread) {
           MyThread mt = (MyThread)paramRunnable; 
       }
       /* Need to access "key" inside MyThread */    
 }