newFixedThreadPool创建固定线程

           long ls = System.currentTimeMillis();
           ExecutorService fixedThreadPool = Executors.newFixedThreadPool(30);
           for (int i = 0; i < 2000; i++) {
               final int index = i;
               fixedThreadPool.execute(new Runnable() {
                   @Override
                   public void run() {
                       System.out.println("thread start" + (index+1));
                       try {
                           Thread.sleep(100);
                       } catch (InterruptedException e) {
                           e.printStackTrace();
                       }
                       System.out.println("thread end" + (index+1));
                   }
               });
           }
           fixedThreadPool.shutdown();
           try {
        	   // 设置等待所有子任务完成  
        	   fixedThreadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.MINUTES);
        	   System.out.println("时间"+(System.currentTimeMillis()-ls));
           } catch (InterruptedException e) {
               e.printStackTrace();  
           }