java - 为什么没有调用run方法？

Question

package threadwork;

public class WorkingWithThreads implements Runnable {

    public static void main(String[] args) {
        WorkingWithThreads wwt = new WorkingWithThreads();
    }

    public WorkingWithThreads() {
        System.out.println("Creating Thread");
        Thread t = new Thread();
        System.out.println("Starting Thread");
        t.start();
    }

    @Override
    public void run() {
        System.out.println("Thread Running");

        for (int i = 0; i < 5; i++) {
            System.out.println("Thread:" + i);
            try {
                Thread.sleep(1);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

当我运行此代码时，它会打印“正在创建线程”和“正在启动线程”。但不打印 Thread Running，这意味着 run 函数根本没有被调用。为什么会这样？

Answer 1

您必须在线程上调用start()才能启动它；例如

Thread t = new Thread();
t.start();

如果您要扩展Thread，您将创建一个新线程并对其调用start()，如下所示:

new MyThread().start();

由于您没有扩展Thread，但您的类实现了Runnable:

new Thread(new WorkingWithThreads()).start();