JAVA多线程—线程死锁

妖狐艹你老母 2024-04-17 22:29 113阅读 0赞

线程死锁：

创建两个字符串a和b，再创建两个线程A和B，让每个线程都用synchronized锁住字符串（A先锁a，再去锁b；B先锁b，再锁a），如果A锁住a，B锁住b，A就没办法锁住b，B也没办法锁住a，这时就陷入了死锁。直接贴代码：

/*
    线程死锁
     */
    public class DeadLock {
    
        public static String str1 = "str1";
        public static String str2 = "str2";
        public static void main(String[] args) {
            Thread t1 = new Thread(new Lock1());
            Thread t2 = new Thread(new Lock2());
            t1.start();
            t2.start();
        }
    }
    
    class  Lock1 implements Runnable{
        @Override
        public void run() {
            try {
                System.out.println("线程"+Thread.currentThread().getName()+"开始运行");
                while (true){
                    synchronized (DeadLock.str1){
                        System.out.println("线程"+Thread.currentThread().getName()+"锁住str1");
                        Thread.sleep(3000);
                        synchronized (DeadLock.str2){
                            System.out.println("线程"+Thread.currentThread().getName()+"锁住str2");
                        }
                    }
                }
            }catch (Exception e){
             e.printStackTrace();
            }
        }
    }
    
    class  Lock2 implements Runnable{
        @Override
        public void run() {
            try {
                System.out.println("线程"+Thread.currentThread().getName()+"开始运行");
                while (true){
                    synchronized (DeadLock.str2){
                        System.out.println("线程"+Thread.currentThread().getName()+"锁住str2");
                        Thread.sleep(3000);
                        synchronized (DeadLock.str1){
                            System.out.println("线程"+Thread.currentThread().getName()+"锁住str1");
                        }
                    }
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }