一、五种状态与六种状态

1.针对操作系统层面

线程的五种状态

2.针对Java API层面

线程的六种状态

• NEW
  初始状态，线程刚创建，没有调用start()方法

    public static void main(String[] args) {

        Thread t1 = new Thread(() -> log.debug("{}","running..."),"t1");

        log.debug("{}",t1.getState());
    }

输出结果：

14:43:34.132 [main] - NEW

• RUNNABLE
  可运行线程的线程状态。处于可运行状态的线程正在Java虚拟机中执行，但它可能正在等待来自操作系统(如处理器)的其他资源。

    public static void main(String[] args) {

        Thread t1 = new Thread(() -> log.debug("{}","running..."),"t1");
        t1.start();
        log.debug("{}",t1.getState());
    }

输出结果：

14:46:48.324 [main] - RUNNABLE

• BLOCKED
  等待监视器锁的阻塞线程的线程状态。

    public static void main(String[] args) throws InterruptedException {
        
        Thread t1 = new Thread(() -> {
            synchronized (New.class){
                while (true){

                }
            }
        },"t1");
        t1.start();
        
        Thread t2 = new Thread(() ->{
            synchronized (New.class){
                log.debug("{}","running");
            }
        });
        t2.start();

        TimeUnit.SECONDS.sleep(1);
        log.debug("{}",t2.getState());
    }

输出结果：

15:01:33.626 [main] - BLOCKED

• WAITING
  等待线程的线程状态，调用wait(),join(),park()方法都会进入此状态

    public static void main(String[] args) throws InterruptedException {
        Thread t1 = new Thread(() ->{
         while (true){

         }
        },"t1");
        t1.start();

        Thread t2 = new Thread(() ->{
            try {
                //t2同步等待t1线程
                t1.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        },"t2");
        t2.start();
        
        TimeUnit.SECONDS.sleep(1);
        log.debug("{}",t2.getState());
    }

输出结果：

15:20:30.439 [main] - WAITING

• TIMED_WAITING
  具有指定等待时间的等待线程的线程状态。调用sleep(),wait(),join(),parkNanos,parkUntil指定时间会进入此状态

    public static void main(String[] args) throws InterruptedException {
        Thread t1 = new Thread(() ->{
            try {
                TimeUnit.SECONDS.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        },"t1");

        t1.start();
        TimeUnit.SECONDS.sleep(1);
        log.debug("{}",t1.getState());
    }

输出结果：

15:20:51.507 [main] - TIMED_WAITING

• TERMINATED
  终止线程的线程状态。线程已完成执行。

    public static void main(String[] args) throws InterruptedException {
        
        Thread t1 = new Thread(() -> log.debug("{}","running..."),"t1");
        t1.start();
        TimeUnit.SECONDS.sleep(1);
        log.debug("{}",t1.getState());

    }

输出结果：

15:27:18.540 [main] - TERMINATED