Java 给一个任务设置超时返回

可以通过CompletableFuture 来执行某个任务，超时后放弃任务。

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
 
public class CompletableFutureTester {
 
    public static void main(String[] argvs) {
        CompletableFuture<String> cf1 = CompletableFuture.supplyAsync(() -> {
            System.out.println("enter cf");
            try {
                //sleep 3秒
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("s1");
            return "done";
        });
 
        try {
            //试图在2秒内得到结果，否则算超时
            String result = cf1.get(2, TimeUnit.SECONDS);
            System.out.println("result is : " + result);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        } catch (TimeoutException e) {
            System.out.println("超时未得到结果");
            e.printStackTrace();
        }
    }
}