Java并发编程 线程生命周期

• 有哪6种状态？
• 每个状态是什么含义
• 状态间的转化图示
• 阻塞状态是什么

每个状态是什么含义

• New
• Runnable
• Blocked
• Waiting
• Timed Waiting
• Terminated

https://www.jianshu.com/p/dfdc150a3e54

image.png

展示线程的NEW、RUNNABLE、Terminated状态

/**
 * 描述：     展示线程的NEW、RUNNABLE、Terminated状态。即使是正在运行，也是Runnable状态，而不是Running。
 */
public class NewRunnableTerminated implements Runnable {

    public static void main(String[] args) {
        Thread thread = new Thread(new NewRunnableTerminated());
        //打印出NEW的状态
        System.out.println(thread.getState());
        thread.start();
        System.out.println(thread.getState());
        try {
            Thread.sleep(6);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //打印出RUNNABLE的状态，即使是正在运行，也是RUNNABLE，而不是RUNNING
        System.out.println(thread.getState());
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //打印出TERMINATED状态
        System.out.println(thread.getState());
    }

    @Override
    public void run() {
        for (int i = 0; i < 1000; i++) {
            System.out.println(i);
        }
    }
}

NEW
RUNNABLE
0
1
2
... 省略
294
295
RUNNABLE
296
297
298
... 省略
998
999
TERMINATED

Process finished with exit code 0

展示Blocked, Waiting, TimedWaiting

/**
 * 描述：     展示Blocked, Waiting, TimedWaiting
 */
public class BlockedWaitingTimedWaiting implements Runnable{
    public static void main(String[] args) {
        BlockedWaitingTimedWaiting runnable = new BlockedWaitingTimedWaiting();
        Thread thread1 = new Thread(runnable);
        thread1.start();

        try {
            Thread.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Thread thread2 = new Thread(runnable);
        thread2.start();

        //打印出Timed_Waiting状态，因为正在执行Thread.sleep(1000);
        System.out.println(thread1.getState());
        //打印出BLOCKED状态，因为thread2想拿得到sync()的锁却拿不到
        System.out.println(thread2.getState());
        try {
            Thread.sleep(1300);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //打印出WAITING状态，因为执行了wait()
        System.out.println(thread1.getState());

    }

    @Override
    public void run() {
        syn();
    }

    private synchronized void syn() {
        try {
            Thread.sleep(1000);
            wait();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

TIMED_WAITING
BLOCKED
WAITING

阻塞状态

一般习惯而言，把Blocked（被阻塞）、Waiting（等待）、Timed_waiting（即使等待）都成为阻塞状态

• 不仅仅是Blocked

特别感谢

悟空