CompletableFuture提供了多个方法，可以支持两个任务的组合执行，提供的方式是runAfter开头的多个方法。
runAfterXXX方法支持等待一个或者两个任务执行完成，然后再执行一个自定义的action，执行自定义action并不使用之前任务的结果，并且执行完也没有返回结果。
我们看一下具体方法：
CompletableFuture<Void> runAfterBoth(CompletionStage<?> other, Runnable action)
CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other, Runnable action)
CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other, Runnable action, Executor executor)
CompletableFuture<Void> runAfterEither(CompletionStage<?> other, Runnable action)
CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other, Runnable action)
CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other, Runnable action, Executor executor)
static CompletableFuture<Void> runAsync(Runnable runnable)
static CompletableFuture<Void> runAsync(Runnable runnable, Executor executor) 我们再来看一下demo：
import java.util.concurrent.CompletableFuture;
/**
* 使用CompletableFuture异步编程 runAfterXXX
* @author www.itzhimei.com
*/
public class FutureTest_12 {
public static void main(String[] args) throws Exception {
CompletableFuture.supplyAsync(()->FutureTest_12.getTaskResult(1000, "Test Task 1"))
.runAfterBoth(CompletableFuture.supplyAsync(()->FutureTest_12.getTaskResult(500, "Test Task 2")), ()->System.out.println("runAfterBoth:两个任务都执行完成了")).join();
System.out.println("==================================================");
long start = System.currentTimeMillis();
CompletableFuture.supplyAsync(()->FutureTest_12.getTaskResult(10000, "Test Task 1"))
.runAfterEither(CompletableFuture.supplyAsync(()->FutureTest_12.getTaskResult(500, "Test Task 2")), ()->System.out.println("runAfterEither:其中一个任务执行完成了")).join();
long end = System.currentTimeMillis();
System.out.println("任务执行时间:" + (end-start));
}
public static String getTaskResult(long sleepTime, String task) {
try {
Thread.sleep(sleepTime);
} catch (InterruptedException e) {
e.printStackTrace();
}
return task;
}
}
/* 输出
runAfterBoth:两个任务都执行完成了
==================================================
runAfterEither:其中一个任务执行完成了
任务执行时间:502
*/