Java中关于LockSupport的简单入门记录

LockSupport的JDK的文档描述：Basic thread blocking primitives for creating locks and other synchronization classes.（对于创建lock和其他同步类的基础线程原语）。在JUC中有大量使用！

1 示例:

在主线程中调用LockSupport.park(currentThread);将组线程阻塞，然后通过子线程完成5秒睡眠换后唤醒主线程。

import java.util.concurrent.locks.LockSupport;

public class LockSupportDemo {

    public static void main(String[] args) {

        //获取当前线程
        final Thread currentThread = Thread.currentThread();
        
        Runnable runnable = new Runnable() {

            @Override
            public void run() {
                try {
                    //睡眠5秒，等待主线程调用park
                    Thread.sleep(5000);
                    System.out.println("子线程进行unpark操作！");
                    // 进行唤醒给定的currentThread线程
                    LockSupport.unpark(currentThread);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        };

        new Thread(runnable).start();
        System.out.println("开始阻塞！");
        // 进行阻塞给定的currentThread线程
        LockSupport.park(currentThread);
        System.out.println("结束阻塞！");

    }

}

示例2：

import java.util.concurrent.locks.LockSupport;

public class LockSupportDemo {

    public static void main(String[] args) {

        //获取当前线程
        final Thread currentThread = Thread.currentThread();
     
        //在park之前先进行一次unpark
        LockSupport.unpark(currentThread);
         
        
        System.out.println("开始阻塞！");
        // 由于在park之前进行了一次unpark，所以会低调本次的park操作。因而不会阻塞在此处
        LockSupport.park(currentThread);
        System.out.println("结束阻塞！");

    }

}