[web-021] java Future和java CompletableFuture的示例

最新推荐文章于 2025-08-17 21:38:20 发布

未济2019

最新推荐文章于 2025-08-17 21:38:20 发布

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文章标签： java

本文链接：https://blog.youkuaiyun.com/lizhe_dashuju/article/details/98360511

本文通过两个Java示例，展示了如何使用Callable和FutureTask实现线程任务的异步执行，以及使用CompletableFuture进行异步任务的链式调用。第一个示例中，通过Callable和FutureTask创建了一个异步任务，该任务在主线程启动后独立运行，并在完成后返回结果。第二个示例中，使用了CompletableFuture来异步执行任务，并在任务完成后获取结果。

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import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;

public class Main {
    private static class Ch {};


    public static void main(String[] args) throws Exception{

        Callable<Ch> onlineChopping = new Callable<Ch>() {
            public Ch call() throws Exception {
                System.out.println("ch：start");
                Thread.sleep(5000);
                System.out.println("ch：ok");
                return new Ch();
            }
        };

        FutureTask<Ch> task = new FutureTask<Ch>(onlineChopping);
        new Thread(task).start();

        Thread.sleep(2000);
        while (!task.isDone()){
            System.out.println("wait");
            Thread.sleep(1000);
        }

    }
}

import java.time.LocalTime;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

public class Main2 {

    public static String work(String name){
        System.out.println(name + " starts at " + LocalTime.now());
        try {
            Thread.sleep(3000);
        }catch (Exception e){
        }finally {
        }
        System.out.println(name + " ends at " + LocalTime.now());
        return name;
    }

    private static void useCompleteableFure() throws InterruptedException, ExecutionException {
        CompletableFuture<Void> fa = CompletableFuture.runAsync(()->work("a"));
        Thread.sleep(1000);
        CompletableFuture<Void> fb = CompletableFuture.runAsync(()->work("b"));
        System.out.println(fa.get());
        System.out.println(fb.get());
    }

    public static void main(String[] args) throws InterruptedException, ExecutionException{
        useCompleteableFure();
    }
}