CompletableFuture 提供了四個靜態方法來創建一個異步操作。
靜態方法如下：
CompletableFuture runAsync(Runnable runnable);
CompletableFuture runAsync(Runnable runnable, Executor executor);
CompletableFuture supplyAsync(Supplier supplier);
CompletableFuture supplyAsync(Supplier supplier, Executor executor);
runAsync 與 supplyAsync 兩者區別：
runAsync方法不支持返回值。
supplyAsync可以支持返回值。
Executor說明：
如果方法存在executor參數，就使用executor執行任務;
否則默認使用公用的ForkJoinPool.commonPool()作爲執行異步任務的線程池。
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());
}
執行結果：
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());
}鄭州人流醫院 http://www.zyfuke.com/
執行結果：
Hello World
null
示例三
public static void main(String[] args) throws ExecutionException, InterruptedException {
// 獲取當前時間戳
CompletableFuture future = CompletableFuture.supplyAsync(System::currentTimeMillis);
System.out.println(future.get());
}
執行結果：
1586245295714
示例四
public static void main(String[] args) throws ExecutionException, InterruptedException {
// 獲取當前時間戳
ExecutorService executor = Executors.newCachedThreadPool();
CompletableFuture future = CompletableFuture.supplyAsync(System::currentTimeMillis,executor);
System.out.println(future.get());
}
執行結果：
1586245295714