private Map<Long,DecryptSignalAndPath> afterDecryptFilePathMap = new HashMap<Long,DecryptSignalAndPath>();//TODO 注意容器垃圾数据的清理工作 
 class DecryptRunnable implements Runnable { 
   private ServerFileBean serverFile; 
   private Long fid;//指向解密文件 
   private CountDownLatch decryptSignal; 
   protected DecryptRunnable(Long fid, ServerFileBean serverFile, CountDownLatch decryptSignal) { 
     this.fid = fid; 
     this.serverFile = serverFile; 
     this.decryptSignal = decryptSignal; 
   } 
   @Override 
   public void run() { 
     //开始解密 
     String afterDecryptFilePath = null; 
     DecryptSignalAndPath decryptSignalAndPath = new DecryptSignalAndPath(); 
     decryptSignalAndPath.setDecryptSignal(decryptSignal); 
     afterDecryptFilePathMap.put(fid, decryptSignalAndPath); 
     afterDecryptFilePath = decryptFile(serverFile); 
     decryptSignalAndPath.setAfterDecryptFilePath(afterDecryptFilePath); 
     decryptSignal.countDown();//通知所有阻塞的线程 
   } 
    
 } 
 class DecryptSignalAndPath { 
   private String afterDecryptFilePath; 
   private CountDownLatch decryptSignal; 
   public String getAfterDecryptFilePath() { 
     return afterDecryptFilePath; 
   } 
   public void setAfterDecryptFilePath(String afterDecryptFilePath) { 
     this.afterDecryptFilePath = afterDecryptFilePath; 
   } 
   public CountDownLatch getDecryptSignal() { 
     return decryptSignal; 
   } 
   public void setDecryptSignal(CountDownLatch decryptSignal) { 
     this.decryptSignal = decryptSignal; 
   } 
 } 

 CountDownLatch decryptSignal = new CountDownLatch(1); 
 new Thread(new DecryptRunnable(fid, serverFile, decryptSignal)).start();//无需拿到新线程句柄，由 CountDownLatch 自行跟踪 
 try { 
   decryptSignal.await(); 
 } catch (InterruptedException e) { 
   // TODO Auto-generated catch block 
 } 

CountDownLatch decryptSignal = afterDecryptFilePathMap.get(fid).getDecryptSignal();   
 try { 
   decryptSignal.await(); 
 } catch (InterruptedException e) { 
   // TODO Auto-generated catch block 
 } 

 class Driver2 { // ... 
  void main() throws InterruptedException { 
   CountDownLatch doneSignal = new CountDownLatch(N); 
   Executor e = ... 
  
   for (int i = 0; i < N; ++i) // create and start threads 
    e.execute(new WorkerRunnable(doneSignal, i)); 
  
   doneSignal.await();      // wait for all to finish 
  } 
 } 
  
 class WorkerRunnable implements Runnable { 
  private final CountDownLatch doneSignal; 
  private final int i; 
  WorkerRunnable(CountDownLatch doneSignal, int i) { 
   this.doneSignal = doneSignal; 
   this.i = i; 
  } 
  public void run() { 
   try { 
    doWork(i); 
    doneSignal.countDown(); 
   } catch (InterruptedException ex) {} // return; 
  } 
  
  void doWork() { ... } 
 }