Question

基本上我的代码如下所示：

private void runFreeThreads() {
    ArrayList<ClassExtendsThread> tmpThreads = new ArrayList<ClassExtendsThread>(freeThreads);
    freeThreads.clear();
    System.out.println("Before the loop");
    for (ClassExtendsThread thread : tmpThreads) {
        thread.start();
    }
    System.out.println("After the loop");
}

问题是我使用this初始化这些主题，而this有一个名为threadReport()的方法，看起来像

public void threadReport(boolean check, ClassExtendsThread someThread) {
        freeThreads.add(someThread);
        if (!check) {
            return;
        }
        System.out.println("Trying to acquire semaphore");
        try {
            reportSem.acquire();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        runFreeThreads();
        }
        System.out.println("Semaphore is released!");
        reportSem.release();
    }

我在这里使用信号量就像一个互斥体，它基本上用1初始化。无论如何，我认为Thread.start()实际上会调用run()然后从父线程调度自己，但事实并非如此。

run方法是：

    public class ClassExtendsThread extends Thread {
        private ThreadController tControl;
        private int threadNo;

        public ClassExtendsThread (int threadNo, ThreadController threadController) {
            tControl = threadController;
            this.threadNo = threadNo;
        }

        public void run() {
            System.out.println("Thread no: " + this.threadNo + " is running");
            tControl.tReport(true, this);
        }
  }

所以我期待这样的结果（我也在run()方法打印一些东西）：

Trying to acquire semaphore
Before the loop
Thread no: 1 is running
Thread no: 2 is running
After the loop
Semaphore is released!
...

但实际上发生的事情是：

Trying to acquire semaphore
Before the loop
Thread no: 1 is running
Thread no: 2 is running
Trying to acquire semaphore
Trying to acquire semaphore

然后它挂起。因为它永远不会退出循环。有没有快速解决方法？

Thread.start（）不从Java中的父线程调度

0 个答案: