如何在退出线程时执行代码

Question

我想在线程死亡之前在最后执行代码。所以我在寻找的是线程的某种dispose（），tearDown（）方法，以确保某些任务在退出线程之前执行。

Answer 1

你可以用代码来在自己的代码一个单独的线程具有try/finally块内执行，并从try称之为的“真正的” Runnable的run方法，像这样：

final Runnable realRunnable = ... // This is the actual logic of your thread 
(new Thread(new Runnable() { 
    public void run() { 
     try { 
      realRunnable.run(); 
     } finally { 
      runCleanupCode(); 
     } 
    } 
})).start(); 

runCleanupCode()的代码将在用于运行实际线程逻辑的相同线程中执行。

Answer 2

以dasblinkenlight的回答远一点（太远）：

class ThreadWithCleanup extends Thread { 
    final Runnable main; 
    final Runnable cleanup; 

    ThreadWithCleanup(Runnable main, Runnable cleanup) { 
     this.main = main; 
     this.cleanup = cleanup; 
    } 

    @Override 
    public void run() { 
     try { 
      main.run(); 
     } finally { 
      cleanup.run(); 
     } 
    } 
} 

public class Demo { 
    public static void main(String[] args) { 
     Runnable m = new Runnable() { 
      @Override 
      public void run() { 
       System.out.println("Hello from main."); 
       throw new RuntimeException("Bleah!"); 
      } 
     }; 
     Runnable c = new Runnable() { 
      @Override 
      public void run() { 
       System.out.println("Hello from cleanup."); 
      } 
     }; 
     ThreadWithCleanup threadWithCleanup = new ThreadWithCleanup(m, c); 
     threadWithCleanup.start(); 
     try { 
      threadWithCleanup.join(); 
     } catch (InterruptedException ex) { 
     } 
    } 
} 

我曾经以为我再也看不到一个正当的理由来扩展Thread类！

Answer 3

其他答案没有考虑到你正在讨论线程池。这是你需要做的：

private static class MyThreadFactory implements ThreadFactory { 
    public Thread newThread(final Runnable r) { 
     return new Thread() { 
      public void run() { 
       try { 
        r.run(); 
       } finally { 
        // teardown code 
       } 
      } 
     }; 
    } 

} 
public static void main(String[] args) { 
    ThreadPoolExecutor exec = new ThreadPoolExecutor(10, 20, 100, TimeUnit.SECONDS, null, new MyThreadFactory()); 
}