LockSupport

LockSupport 是一个非常方便实用的线程阻塞工具,它可以在线程内任意位置让线程阻塞,

LockSupport 的静态方法park()可以阻塞当前线程,类似的还有parkNanos(),parkUntil()等方法,它们实现了一个限时的等待.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
public class LockSupportDemo {
    public static Object u=new Object();
    static ChangeObjectThread t1 =new ChangeObjectThread("t1");
    static ChangeObjectThread t2 =new ChangeObjectThread("t2");
    public static class ChangeObjectThread extends Thread
    {
        public  ChangeObjectThread(String name)
        {
            super.setName(name);
        }
        public void run()
        {
            synchronized(u)
            {
                System.out.println("in "+getName());
                LockSupport.park(); //让当前线程阻塞
            }
        }
    }
    public static void main(String[] args) throws Exception
    {
        t1.start();
        Thread.sleep(1000);
        t2.start();
        System.out.println("123");
        LockSupport.unpark(t1); //唤醒t1线程
        LockSupport.unpark(t2);	// 唤醒t2线程.
        t1.join();
        t2.join();
    }
}
1
2
3
in t1
123
in t2