Java中使用Atomic*实现原子锁线程安全

谁践踏了优雅 2023-06-12 09:17 17阅读 0赞

原子锁类型是JDK Atomic\* 相关的类。如AtomicInteger、AtomicLong 等等。

package com.forestar.xht.util;
    
    import java.util.concurrent.atomic.AtomicInteger;
    
    /**
     * 原子锁
     * 
     * @author PJL
     *
     */
    public class AtomicLock {
    
    	private static AtomicInteger flag = new AtomicInteger(0);
    	
    	/**
    	 * 获取锁的值
    	 * @return
    	 */
    	public static int getLockValue() {
    		return flag.intValue();
    	}
    
    	/**
    	 * 阻塞
    	 */
    	public static void blockingUntilUnlock() {
    		while (flag.intValue() == 1) {
    			try {
    				Thread.sleep(1);
    			} catch (InterruptedException e) {
    				e.printStackTrace();
    			}
    		}
    	}
    
    	/**
    	 * 加锁
    	 * 
    	 * @return
    	 */
    	public static int lock() {
    		blockingUntilUnlock();
    
    		if (flag.intValue() == 0) {
    			return flag.incrementAndGet();
    		}
    		return flag.intValue();
    	}
    
    	/**
    	 * 去锁
    	 * 
    	 * @return
    	 */
    	public static int unlock() {
    		if (flag.intValue() == 1) {
    			return flag.decrementAndGet();
    		}
    		return flag.intValue();
    	}
    
    	public static void main(String[] args) {
    		for (int i = 1; i <= 10; i++) {
    			String name = "thread-" + i;
    			new Thread(() -> {
    				AtomicLock.lock();
    				System.out.println(name + "加锁"+" "+" 值 "+AtomicLock.getLockValue());
    				AtomicLock.unlock();
    				System.out.println(name + "去锁"+" "+" 值 "+AtomicLock.getLockValue());
    			}).start();
    		}
    	}
    
    }

测试结果：

thread-1加锁  值 1
    thread-1去锁  值 0
    thread-4加锁  值 1
    thread-4去锁  值 0
    thread-7加锁  值 1
    thread-7去锁  值 0
    thread-8加锁  值 1
    thread-8去锁  值 0
    thread-9加锁  值 1
    thread-9去锁  值 0
    thread-10加锁  值 1
    thread-10去锁  值 0
    thread-2加锁  值 1
    thread-2去锁  值 0
    thread-3加锁  值 1
    thread-3去锁  值 0
    thread-5加锁  值 1
    thread-5去锁  值 0
    thread-6加锁  值 1
    thread-6去锁  值 0