多线程入门（3）：线程的生命周期

川长思鸟来 2023-06-27 12:55 43阅读 0赞

//java.lang.Thread.State
    public enum State {
        NEW,
        RUNNABLE,
        BLOCKED,
        WAITING,
        TIMED_WAITING,
        TERMINATED;
    }

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# 1 状态间的转化图示 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly95dWFueXUuYmxvZy5jc2RuLm5ldA_size_16_color_FFFFFF_t_70][]

> 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。

/**
     * 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 {
        public static void main(String[] args) {
            Thread thread = new Thread(() -> {
                for (int i = 0; i < 1000; i++) {
                    System.out.println(i);
                }
            });
            //打印出NEW的状态
            System.out.println(thread.getState());
            thread.start();
            System.out.println(thread.getState());
            try {
                Thread.sleep(10);
            } 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());
        }
    }

>  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();
            Thread thread2 = new Thread(runnable);
            thread2.start();
            try {
                Thread.sleep(5);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            //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();
        }
        /**
         * 线程1进入方法后sleep(1000)
         * 线程2陷入阻塞状态(Blocked)
         */
        private synchronized void syn() {
            try {
                Thread.sleep(1000);
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

--------------------

# 2 阻塞状态 #

> 一般习惯而言，把 Blocked(被阻塞)、Waiting(等待)、Timed\_waiting(计时等待)都称为阻塞状态

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