多线程访问同一资源第一步：利用synchronized吃苹果,利用lock锁机制吃梨

/*
 *             多线程访问同一资源第一步 
 * 三个线程消费500个苹果 使用synchronized（ 同步代码快 ）
 * 三个线程消费500个梨    使用Lock（Lock锁机制）
 */

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

//将同步代码块之间的代码进行同步  吃苹果
class Apple implements Runnable {
	private int a;

	public Apple(int a) {
		this.a = a;
	}

	@Override
	public void run() {
		for (int i = 0; i < 500; i++) {

			synchronized (Apple.class) {
				if (a > 0) {
					System.out.println(Thread.currentThread().getName() + "吃第" + (a--) + "个苹果");
				}

			}

		}

	}
}


//将lock 和 unlock 之间的代码锁定    吃梨
class Pear implements Runnable {
	private int a;
	private final Lock lock = new ReentrantLock();

	public Pear(int a) {
		this.a = a;
	}

	@Override
	public void run() {
		for (int i = 0; i < 500; i++) {
			lock.lock();
			try {
				if (a > 0) {
					System.out.println(Thread.currentThread().getName() + "吃第" + (a--) + "个梨");
				}
			} finally {
				lock.unlock();
			}

		}

	}
}

public class ThreadDemo01 {

	public static void main(String[] args) {
		/*Apple apple = new Apple(500);
		Thread a1 = new Thread(apple);
		Thread a2 = new Thread(apple);
		Thread a3 = new Thread(apple);
		a1.start();
		a2.start();
		a3.start();*/
		Pear pear = new Pear(500);
		Thread b1 = new Thread(pear);
		Thread b2 = new Thread(pear);
		Thread b3 = new Thread(pear);
		b1.start();
		b2.start();
		b3.start();
	}
}