【重点：Lock】把sychronized改为lock的方法

最新推荐文章于 2024-05-23 14:24:26 发布

闲着没事_玩玩JAVA

最新推荐文章于 2024-05-23 14:24:26 发布

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本文通过两个Java示例对比了使用synchronized关键字与ReentrantLock实现线程同步的区别。前者直接在run方法上加锁，后者则需手动获取和释放锁。两者均能确保线程安全地递减共享变量。

sychronized

package com.xiaozhi.threadlocal2;


public class Test {

	public static void main(String[] args) {
		MyRun myRun=new MyRun();
		for(int i=0;i<10;i++)
			new Thread(myRun).start();
	}
}

class MyRun implements Runnable {
	int num = 10;
	public synchronized void run() {
			while(num > 0) {
				try {Thread.sleep(1000);} catch (InterruptedException e) {}
				num--;
				System.out.println(num);
			}
		
	}
}

lock

package com.xiaozhi.threadlocal2;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class Test {

	public static void main(String[] args) {
		MyRun myRun=new MyRun();
		for(int i=0;i<10;i++)
			new Thread(myRun).start();
	}
}

class MyRun implements Runnable {
	int num = 10;
	Lock lock = new ReentrantLock();
	public /*synchronized*/ void run() {
			lock.lock();
			try {
				while(num > 0) {
					try {Thread.sleep(1000);} catch (InterruptedException e) {}
					num--;
					System.out.println(num);
				}
			} catch (Exception e) {
				e.printStackTrace();
			}finally{
				lock.unlock();
			}
			
		
	}
}