CompletableFuture 提供了四个静态方法来创建一个异步操作。
静态方法如下：
CompletableFuture runAsync(Runnable runnable);
CompletableFuture runAsync(Runnable runnable, Executor executor);
CompletableFuture supplyAsync(Supplier supplier);
CompletableFuture supplyAsync(Supplier supplier, Executor executor);
runAsync 与 supplyAsync 两者区别：
runAsync方法不支持返回值。
supplyAsync可以支持返回值。
Executor说明：
如果方法存在executor参数，就使用executor执行任务;
否则默认使用公用的ForkJoinPool.commonPool()作为执行异步任务的线程池。
示例一
public static void main(String[] args) throws ExecutionException, InterruptedException {
CompletableFuture future = CompletableFuture.runAsync(() -> System.out.println("Hello World"));
System.out.println(future.get());
}
执行结果：
Hello World
null
示例二
public static void main(String[] args) throws ExecutionException, InterruptedException {
ExecutorService executor = Executors.newCachedThreadPool();
CompletableFuture future = CompletableFuture.runAsync(() -> System.out.println("Hello World"),executor);
System.out.println(future.get());
}郑州人流医院 http://www.zyfuke.com/
执行结果：
Hello World
null
示例三
public static void main(String[] args) throws ExecutionException, InterruptedException {
// 获取当前时间戳
CompletableFuture future = CompletableFuture.supplyAsync(System::currentTimeMillis);
System.out.println(future.get());
}
执行结果：
1586245295714
示例四
public static void main(String[] args) throws ExecutionException, InterruptedException {
// 获取当前时间戳
ExecutorService executor = Executors.newCachedThreadPool();
CompletableFuture future = CompletableFuture.supplyAsync(System::currentTimeMillis,executor);
System.out.println(future.get());
}
执行结果：
1586245295714