线程池模拟高并发

Integer taskCount =700;
// 锁住所有线程，等待并发执行
final CountDownLatch begin =new CountDownLatch(1);
final ExecutorService exec =Executors.newFixedThreadPool(taskCount);
for (int index =0; index < taskCount; index++){
final int NO= index +1;
Runnable run =new Runnable() {
        @Override
        public void run() {
            try {
                // 等待，所有一起执行
                begin.await();
                //开始模拟等待。。。
                //Thread.sleep((long) (Math.random() * 10000));
            }catch (InterruptedException e){
                e.printStackTrace();
            }finally {
            }
        }
    };
    exec.submit(run);
}
System.out.println("开始执行");
// begin减一，开始并发执行
begin.countDown();
//关闭执行
exec.shutdown();