Java多線程-線程狀態

線程狀態

6個狀態定義：java.lang.Thread.State

1. New: 還沒有啓動的線程的線程狀態。
2. Runnable: 可運行線程的線程狀態，等待CPU調度。
3. Blocked: 線程阻塞等待監視器鎖定的線程狀態。處於synchronized同步代碼塊或方法中被阻塞。
4. Waiting: 等待線程的線程狀態。下列不帶超時的方式：Object.wait、Thread.join、LockSupport.park
5. Timed Waiting: 具備指定等待時間的等待線程的線程狀態。下列超時的方式：Thread.sleep、Object.wait、Thread.join、LockSupport.parkNanos、LockSupport.parkUntil

常見線程狀態切換

新建->運行->終止

Thread thread1 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("thread1當前狀態：" + Thread.currentThread().getState().toString());
                System.out.println("thread1 執行了");
            }
        });
System.out.println("沒調用start方法，thread1當前狀態：" + thread1.getState().toString());
thread1.start();
Thread.sleep(2000L); // 等待thread1執行結束，再看狀態
System.out.println("等待兩秒，再看thread1當前狀態：" + thread1.getState().toString());

新建->運行->等待->運行->終止

Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {// 將線程2移動到等待狀態，1500後自動喚醒
                    Thread.sleep(1500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("thread2當前狀態：" + Thread.currentThread().getState().toString());
                System.out.println("thread2 執行了");
            }
        });
System.out.println("沒調用start方法，thread2當前狀態：" + thread2.getState().toString());
thread2.start();
System.out.println("調用start方法，thread2當前狀態：" + thread2.getState().toString());
Thread.sleep(200L); // 等待200毫秒，再看狀態
System.out.println("等待200毫秒，再看thread2當前狀態：" + thread2.getState().toString());
Thread.sleep(3000L); // 再等待3秒，讓thread2執行完畢，再看狀態
System.out.println("等待3秒，再看thread2當前狀態：" + thread2.getState().toString());

新建->運行->阻塞->運行->終止

Thread thread3 = new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (Demo2.class) {
                    System.out.println("thread3當前狀態：" + Thread.currentThread().getState().toString());
                    System.out.println("thread3 執行了");
                }
            }
        });
synchronized (Demo2.class) {
    System.out.println("沒調用start方法，thread3當前狀態：" + thread3.getState().toString());
    thread3.start();
    System.out.println("調用start方法，thread3當前狀態：" + thread3.getState().toString());
    Thread.sleep(200L); // 等待200毫秒，再看狀態
    System.out.println("等待200毫秒，再看thread3當前狀態：" + thread3.getState().toString());
}
Thread.sleep(3000L); // 再等待3秒，讓thread3執行完畢，再看狀態
System.out.println("等待3秒，讓thread3搶到鎖，再看thread3當前狀態：" + thread3.getState().toString());