ScheduledThreadPoolExecutor 关于 shutdown 的使用

• shutdown()
  无法直接停止。

final ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1);
executor.schedule(new Runnable() {
    @Override
    public void run() {
        System.out.println("+++ executor run.");
    }
}, 5, TimeUnit.SECONDS);
new Thread(new Runnable() {
    @Override
    public void run() {
        HCTools.sleep(1, TimeUnit.SECONDS);
        executor.shutdown();
        System.out.println("--- executor shutdown.");
    }
}).start();

输出结果：

--- executor shutdown.
+++ executor run.

• shutdownNow()
  调用后会立即停止。

final ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1);
executor.schedule(new Runnable() {
    @Override
    public void run() {
        System.out.println("+++ executor run.");
    }
}, 5, TimeUnit.SECONDS);
new Thread(new Runnable() {
    @Override
    public void run() {
        HCTools.sleep(1, TimeUnit.SECONDS);
        executor.shutdownNow();
        System.out.println("--- executor shutdownNow.");
    }
}).start();

输出结果：

--- executor shutdownNow.