java_多线程小练习

package com.fy.t1;
/**
 * 创建线程2：
 * 1.实现Runnable接口
 * 2.覆盖run()方法
 * 3.创建实现类方法
 * 4.创建线程对象
 * @author z方圆
 *
 */

public class TestCreateThread {
	public static void main(String[] args) {
		MyRunnable mr = new MyRunnable();
		Thread t2 = new Thread(mr);
		t2.start();
	}
}

class MyRunnable implements Runnable {
	public void run() {
		for(int i = 0; i <= 50; i++) {
			System.out.println("MyRunnable : " +i);
		}
	}
}

package com.fy.t1;

public class TestThreadSafeQuestions {
	public static void main(String[] args) throws InterruptedException {
		String[] nums = new String[5];
		Thread t1 = new Thread(new Task1(nums));
		Thread t2 = new Thread(new Task2(nums));
		t1.start();
		t2.start();
		
		//两个线程共享堆中的同一个对象（地址）。各自是独自运行的
		Thread.sleep(5000);
		for(int i = 0; i < nums.length; i++) {
			System.out.println(nums[i] + "\t");
		}
	}
}

class Task1 implements Runnable{
	String[] nums;
	public Task1(String[] nums) {
		this.nums = nums;
	} 
	public void run() {
		synchronized(nums) {//对共享资源加锁，拿到锁才能执行原子操作
			System.out.println(Thread.currentThread().getName() + "拿到了锁，开始执行任务");
			try {
				Thread.sleep(5000);
			}catch(InterruptedException e) {
				
				e.printStackTrace();
				
			}
			//原子操作
			for(int i = 0; i < nums.length; i++) {
				
				if(nums[i] == null) {
					
					System.out.println(Thread.currentThread().getName()+"进来修改下标"+i);
					nums[i] = "Hello";
					break;
				}
			}
		}
	} 
}

class Task2 implements Runnable{
	String[] nums;
	public Task2(String[] nums) {
		this.nums = nums;
	}
		public void run() {
			synchronized(nums) {//对共享资源加锁！拿到锁，才能执行原子操作
				//原子操作
				System.out.println(Thread.currentThread().getName()+"拿到了锁，开始执行任务！");
				try {
					Thread.sleep(5000);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				for(int i = 0;i<nums.length;i++) {
					if(nums[i] == null) {
						System.out.println(Thread.currentThread().getName()+"进来修改下标"+i);
						nums[i] = "World";
						break;
				}
			}
		}
	}
}

本文地址：https://blog.csdn.net/zhu_fangyuan/article/details/107388821