JDK 中用 Thread.State 枚举表示了线程的几种状态

• 线程状态转换图
  

• 使用程序查看线程状态
  创建 T 线程，然后输出此时的状态，再启动线程，利用循环，查看线程状态，只要线程没终止，就会不停的输出状态

public class ThreadState_ {
    public static void main(String[] args) throws InterruptedException {
        T t = new T();
        System.out.println(t.getName() + " 状态 " + t.getState());
        t.start();

        while (Thread.State.TERMINATED != t.getState()) {
            System.out.println(t.getName() + " 状态 " + t.getState());
            Thread.sleep(500);
        }

        System.out.println(t.getName() + " 状态 " + t.getState());

    }
}

class T extends Thread {
    @Override
    public void run() {
        while (true) {
            for (int i = 0; i < 5; i++) {
                System.out.println("hi " + i);
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            break;
        }
    }
}