死锁-嵌套容易发生死锁-蒲公英云

死锁-嵌套容易发生死锁

朱雀 2022-06-10 00:45 286阅读 0赞

直接看例子：

public class DealThread implements Runnable{
    public String username;
    public Object lock1=new Object();
    public Object lock2=new Object();
    public void setFlag(String username){
        this.username=username;
    }
    @Override
    public void run() {
        if(username.equals("a")){
            synchronized (lock1){
                try {
                    System.out.println("username = "+username);
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized (lock2){
                    System.out.println("按lock1->lock2代码顺序执行了");
                }
            }
        }
        if(username.equals("b")){
            synchronized (lock2){
                try {
                    System.out.println("username = "+username);
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized (lock1){
                    System.out.println("按 lock2->lock1代码顺序执行了");
                }
            }
        }
    }
}
public class Run {
    public static void main(String[] args){
        try {
            DealThread t1=new DealThread();
            t1.setFlag("a");
            Thread thread1=new Thread(t1);
            thread1.start();
            Thread.sleep(100);
            t1.setFlag("b");
            Thread thread2=new Thread(t1);
            thread2.start();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}