private Semaphore semaphore;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        semaphore = new Semaphore(5);

        for (int i = 0; i < 1000; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    showLog();
                }
            }).start();
        }


    }
    private void showLog(){
        try {
            semaphore.acquire();
            Log.i("xqxinfo","线程:"+Thread.currentThread().getName()+"执行了一个acquire请求操作");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        // 线程休眠1s
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        semaphore.release();
        Log.i("xqxinfo","线程:"+Thread.currentThread().getName()+"执行了一个release请求操作");


    }