java的查看死锁

柔情只为你懂 2023-07-23 08:57 24阅读 0赞

## java的查看死锁 ##

1.锁是个非常有用的工具，运用场景非常多，因为它使用起来非常简单，而且易于理解。但  
同时它也会带来一些困扰，那就是可能会引起死锁，一旦产生死锁，就会造成系统功能不可  
用；

/** * Created by ls on 2020/4/7. * 演示死锁 */
    public class DeadLockDemo { 
    
        private static String A = "A";
        private static String B = "B";
        public static void main(String[] args) { 
            new DeadLockDemo().deadLock();
        }
        private void deadLock() { 
            Thread t1 = new Thread(new Runnable() { 
                public void run() { 
                    synchronized (A) { 
                        try {  Thread.currentThread().sleep(2000);
                        } catch (InterruptedException e) { 
                            e.printStackTrace();
                        }
                        synchronized (B) { 
                            System.out.println("1");
                        }
                    }
                }
            });
            Thread t2 = new Thread(new Runnable() { 
    
                public void run() { 
                    synchronized (B) { 
                        synchronized (A) { 
                            System.out.println("2");
                        }
                    }
                }
            });
            t1.start();
            t2.start();
        }
    }

**2.通过 jstack pid 查看**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70]  
以下线程信息告诉我们是DeadLockDemo类的第33行和第23行引起的死锁  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70 1]  
**3.通过Jconsole 查看**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70 4]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70 5]  
参考:《Java并发编程的艺术》

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