目录

• 构造几个死锁的例子（Java ）
  • 1
  • 2
  • 3

构造几个死锁的例子（Java ）

1

public class Deadlock {
    public static void main(String[] args) {
        final A a1 = new A("a1");
        final A a2 = new A("a2");
        a1.setA(a2);
        a2.setA(a1);
        Thread t1 = new Thread(()->{
            a1.method1();
        });
        Thread t2 = new Thread(()->{
            a2.method1();
        });
        t1.start();
        t2.start();
    }
}
class A {
    String name;
    A a;
    public A(String name) {
        this.name = name;
    }
    public void setA(A a) {
        this.a = a;
    }
    synchronized void method1() {
        System.out.println(Thread.currentThread().getName() + ": 锁住了" + name);
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(Thread.currentThread().getName() + ": 我在等待" + a.name);
        a.method2();
    }
    synchronized void method2() {
        System.out.println(Thread.currentThread().getName() + ": 我得到了" + name);
        System.out.println(Thread.currentThread().getName() + ": " + name + "." + a.name + ".method2()");
    }
}

运行结果：

2

public class Deadlock {
    public static void main(String[] args) {

        Thread t1 = new Thread(()->{
            A.method1();
        });
        Thread t2 = new Thread(()->{
            B.method1();
        });
        t1.start();
        t2.start();
    }
}
class A {
    synchronized static void method1() {
        System.out.println(Thread.currentThread().getName() + ": 锁住了" + A.class);
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(Thread.currentThread().getName() + ": 我在等待" + B.class);
        B.method2();
    }
    synchronized static void method2() {
        System.out.println(Thread.currentThread().getName() + ": 获得了" + A.class);
        System.out.println(Thread.currentThread().getName() + ": " + A.class + ".method2");
    }
}
class B {
    synchronized static void method1() {
        System.out.println(Thread.currentThread().getName() + ": 锁住了" + B.class);
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(Thread.currentThread().getName() + ": 我在等待" + A.class);
        A.method2();
    }
    synchronized static void method2() {
        System.out.println(Thread.currentThread().getName() + ": 获得了" + B.class);
        System.out.println(Thread.currentThread().getName() + ": " + B.class + ".method2");
    }
}

运行结果：

3

public class Deadlock {
    public static void main(String[] args) {
        final String lock1 = "lock1";
        final String lock2 = "lock2";
        Thread t1 = new Thread(()->{
            synchronized (lock1) {
                System.out.println(Thread.currentThread().getName() + ": 锁住了" + lock1);
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName() + ": 在等待" + lock2);
                synchronized (lock2) {
                    System.out.println(Thread.currentThread().getName() + ": 获得了" + lock2);
                }
            }
        });
        Thread t2 = new Thread(()->{
            synchronized (lock2) {
                System.out.println(Thread.currentThread().getName() + ": 锁住了" + lock2);
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName() + ": 在等待" + lock1);
                synchronized (lock1) {
                    System.out.println(Thread.currentThread().getName() + ": 获得了" + lock1);
                }
            }
        });
        t1.start();
        t2.start();
    }
}

运行结果：