Java编写一个死锁的程序

ゝ一世哀愁。 2022-03-18 15:40 264阅读 0赞

死锁是在多线程编程中常常遇到的问题，现在用java编写一个简单的死锁程序。

程序在main()方法中启动2个线程，“线程-A”和“线程-B”。 线程-A 先拿到 lockA，再寻求拿到 lockB；线程-B 先拿到locB，再需求拿到lockA，如下图，于是变成循环等待，造成死锁。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4MjE1MDQy_size_16_color_FFFFFF_t_70]  
代码

public class DeadLockDemo {
     
    	public static void main(String[] args) {
    		Object lockA = new Object();
    		Object lockB = new Object();
    		new Thread(new Runnable() {
    			@Override
    			public void run() {
    				String name = Thread.currentThread().getName();
    				synchronized (lockA) {
    					System.out.println(name + " got lockA,  want LockB");
    					try {
    						Thread.sleep(100);
    					} catch (InterruptedException e) {
     
    						e.printStackTrace();
    					}
    					synchronized (lockB) {
    						System.out.println(name + " got lockB");
    						System.out.println(name + ": say Hello!");
    					}
    				}
    			}
    		}, "线程-A").start();
     
    		new Thread(new Runnable() {
    			@Override
    			public void run() {
     
    				String name = Thread.currentThread().getName();
    				synchronized (lockB) {
    					System.out.println(name + " got lockB, want LockA");
    					try {
    						Thread.sleep(100);
    					} catch (InterruptedException e) {
     
    						e.printStackTrace();
    					}
    					synchronized (lockA) {
    						System.out.println(name + " got lockA");
    						System.out.println(name + ": say Hello!");
    					}
    				}
     
    			}
    		}, "线程-B").start();
    	}
    }

运行结果：

线程-A got lockA, want LockB  
线程-B got lockB, want LockA

程序死锁了，每个线程都不能完成。  
转自：[https://blog.csdn.net/xidianliuy/article/details/51568073][https_blog.csdn.net_xidianliuy_article_details_51568073]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4MjE1MDQy_size_16_color_FFFFFF_t_70]: /images/20220318/0db2fb9252db4fb7bb74ab8d268c0d96.png
[https_blog.csdn.net_xidianliuy_article_details_51568073]: https://blog.csdn.net/xidianliuy/article/details/51568073