Java CompletableFuture（1）

Java CompletableFuture（1）

 private Long longTimeWork() { try { //模拟耗时操作，特意阻塞5秒。 TimeUnit.SECONDS.sleep(5); } catch (InterruptedException e) { e.printStackTrace(); } return System.currentTimeMillis(); } @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); System.out.println("时间1:" + System.currentTimeMillis()); CompletableFuture<Long> future = CompletableFuture.supplyAsync(() -> longTimeWork()); System.out.println("时间2:" + System.currentTimeMillis()); Future<Long> f = future.whenComplete((v, a) -> { System.out.println("时间3:" + System.currentTimeMillis()); System.out.println("v: " + v); System.out.println("a: " + a); System.out.println("时间4:" + System.currentTimeMillis()); }); System.out.println("时间5:" + System.currentTimeMillis()); }

输出：

06-12 16:28:23.157 4686-4686/zhangphil.test I/System.out: 时间1:1528792103157 06-12 16:28:23.161 4686-4686/zhangphil.test I/System.out: 时间2:1528792103161 06-12 16:28:23.162 4686-4686/zhangphil.test I/System.out: 时间5:1528792103162 06-12 16:28:28.164 4686-4710/zhangphil.test I/System.out: 时间3:1528792108164 06-12 16:28:28.165 4686-4710/zhangphil.test I/System.out: v: 1528792108164 a: null 时间4:1528792108165