java Runnable run()方法返回一个值

Question

根据java doc,Runnable方法void run()不能返回值.我不知道是否有任何解决方法.

其实我有一个调用的方法:

public class Endpoint{
    public method_(){
       RunnableClass runcls = new RunnableClass();
       runcls.run()
    }
}

wheren方法run()是:

public class RunnableClass implements Runnable{

    public jaxbResponse response;
        public void run() {
            int id;
            id =inputProxy.input(chain);
            response = outputProxy.input();

        }
}

我想要访问response变量method_()是否可能？

Answer 1

使用Callable<V>而不是使用Runnable接口.

例:

public static void main(String args[]) throws Exception {
    ExecutorService pool = Executors.newFixedThreadPool(3);
    Set<Future<Integer>> set = new HashSet<Future<Integer>>();
    for (String word: args) {
      Callable<Integer> callable = new WordLengthCallable(word);
      Future<Integer> future = pool.submit(callable);
      set.add(future);
    }
    int sum = 0;
    for (Future<Integer> future : set) {
      sum += future.get();
    }
    System.out.printf("The sum of lengths is %s%n", sum);
    System.exit(sum);
  }

在此示例中,您还需要实现WordLengthCallable类,该类实现Callable接口.

Answer 2

public void check() {
    ExecutorService executor = Executors.newSingleThreadExecutor();
    Future<Integer> result = executor.submit(new Callable<Integer>() {
        public Integer call() throws Exception {
            return 10;
        }
    });

    try {
        int returnValue = result.get();
    } catch (Exception exception) {
       //handle exception
    }
}

Answer 3

看看Callable类.这通常通过执行程序服务提交

它可以返回线程完成时返回的future对象

Answer 4

是的，有解决方法。只需使用队列并将您想要返回的值放入其中。并从另一个线程中获取此值。

public class RunnableClass implements Runnable{

        private final BlockingQueue<jaxbResponse> queue;


        public RunnableClass(BlockingQueue<jaxbResponse> queue) {
            this.queue = queue;
        }

        public void run() {
            int id;
            id =inputProxy.input(chain);
            queue.put(outputProxy.input());
        }
    }


    public class Endpoint{
        public method_(){
            BlockingQueue<jaxbResponse> queue = new LinkedBlockingQueue<>();

            RunnableClass runcls = new RunnableClass(queue);
            runcls.run()

            jaxbResponse response = queue.take(); // waits until takes value from queue
        }
    }