java并发LockSupport

Posted 2022-06-22 juncaif

java并发LockSupport

LockSupport是阻塞和唤醒线程的重要类。
park()方法使得当前线程阻塞
unpark(Thread thread)唤醒线程

例子

可以把注释取消再执行，就会发现park()方法使得当前线程阻塞会使得main线程阻塞，无法结束。

package com.java.javabase.thread.base.concurrent.lock;

import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.locks.LockSupport;

@Slf4j
public class LockSupportTest 
    /**
     * @author
     * @version
     * @since
     */
    private static Object object = new Object();
    private static int size = 10;
    private static int sum = 0;

    public static void main(String[] args) 
        Thread t1 = new Thread() 
            @Override
            public void run() 
                for (int i = 0; i < size; i++) 
                    sum += i;

                
                LockSupport.park();
                log.info(" sum :", Thread.currentThread().getName(),sum);
            
        ;
        Thread t2 = new Thread() 
            @Override
            public void run() 
                for (int i = 0; i < size; i++) 
                    sum += i;
                
                log.info(" sum :",Thread.currentThread().getName(), sum);
            
        ;
        t1.start();
        //t2.start();
        log.info("current thread is ",Thread.currentThread().getName());
        //LockSupport.park(t2);
        LockSupport.unpark(t1);
        //LockSupport.unpark(t2);


    

结果

2019-08-09 11:40:15,219   [main] INFO  LockSupportTest  - current thread is main
2019-08-09 11:40:15,219   [Thread-0] INFO  LockSupportTest  - Thread-0 sum :45