java - Java 中的多线程控制

Question

我有一个“可运行”线程，它正在启动几个“可调用”线程，并且我想在上述所有线程完成其工作时显示结果。

最好的方法是什么？

我的代码如下

Connector.java(启动可运行线程)

  public class Connector {
                      private static void anyFileConnector() {
                    // Starting searching Thread
                        ExecutorService executor = Executors.newFixedThreadPool(100);
                        executor.submit(traverse, executor);
//HERE I WANT MY ALL SEARCH RESULTS/OUTPUT : CURRENTLY IT IS STARTING OTHER THREADS AND NOT SHOWING ME ANY RESULTS BECAUSE NONE OF THEM WAS FINISHED.(IN CONSOLE, I WAS ABLE TO SEE RESULTS FROM ALL THE THREADS
        setSearchResult(traverse.getResult());

                    executor.shutdown();
            }
    }

Traverse.java(可运行线程) 我正在使用 ExecutorCompletionService 来处理它......但它没有产生任何区别。 :(

public class Traverse implements Runnable {
    public void run() {

    ExecutorService executor = Executors.newFixedThreadPool(100);
    ExecutorCompletionService<List<ResultBean>> taskCompletionService =
            new ExecutorCompletionService<List<ResultBean>>(executor);
    try (DirectoryStream<Path> stream = Files
            .newDirectoryStream(dir)) {
                Search newSearch = new Search();
                taskCompletionService.submit(newSearch);
     }
    list.addAll(taskCompletionService.take().get());
    }
}

Search.java(可调用线程)

public class Search implements Callable<List<ResultBean>> {
 public List<ResultBean> call() {
        synchronized (Search.class) {
// It will return results
            return this.search();
        }
    }

}

Answer 1

选择CyclicBarrier，您将能够实现这一目标。 一旦所有线程完成其工作，循环屏障就会执行任务，您可以在此处打印结果。

检查CyclicBarrier的工作情况:http://javarevisited.blogspot.com/2012/07/cyclicbarrier-example-java-5-concurrency-tutorial.html