Question

我有一些Task执行可以挂起的I / O阻塞操作（从URL获取文件）

task = new Task<List<WSDLOperation>>() {
            @Override
            protected List<WSDLOperation> call() {
                List<WSDLOperation> services = new ArrayList<>();
                try {
                    services = WSDLService.createService(wsdlURL).getOperations();
                } catch (Exception ex) {
                    LOG.log(Level.WARNING, "Can't reach {0}", wsdlURL);
                }
                return services;
            }
        };

    }

方法createService可以永远等待而不会抛出任何Exception。（我使用Main类中定义的全局（static public）ExecutorService执行任务。

Answer 1

超时后如何使用未来和取消任务：

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class Test {
    public static void main(String[] args) throws Exception {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        Task t = new Task();
        Future<String> future = executor.submit(t);

        try {
            System.out.println("Started..");
            System.out.println(future.get(5, TimeUnit.SECONDS)); // throws
                                                                    // TimeoutException
            System.out.println("Finished!");
        } catch (TimeoutException e) {
            future.cancel(true);
            System.out.println("Terminated!");
        }
    }
}

class Task implements Callable<String> {
    @Override
    public String call() throws Exception {
        for (int i = 0; i < 1000; i++) {
            Thread.sleep(1000);
            System.out.println("task running!");
        }
        return "Ready!";
    }
}

Answer 2

您正在使用ExecutorService，因此您可以在提交任务后执行此操作：

ExecutorService executor = // ...  
Future<?> future = executor.submit(task);
future.get(5, TimeUnit.MINUTES); // timeout 5 mins

如何在超时后取消任务？

2 个答案: