java线程同步入门例子

使用同一个对象锁+synchronized实现线程同步

class RunnableCase2 implements Runnable{ public void run() { synchronized (this) { try { System.out.println(Thread.currentThread().getId()+"-start"); Thread.sleep(5000); System.out.println(Thread.currentThread().getId()+"-end"); } catch (InterruptedException e) { e.printStackTrace(); } } } }

测试

RunnableCase2 r2 = new RunnableCase2(); Thread t1 = new Thread(r2); Thread t2 = new Thread(r2); t1.start(); t2.start();

输出

9-start 9-end 10-start 10-end

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以下不能实现线程同步，因为不是用的同一个对象锁

class ThreadCase2 extends Thread{ public void run(){ synchronized(this){ try { System.out.println(Thread.currentThread().getId()+"-start"); Thread.sleep(5000); System.out.println(Thread.currentThread().getId()+"-end"); } catch (InterruptedException e) { e.printStackTrace(); } } } }

ThreadCase2 t1 = new ThreadCase2(); ThreadCase2 t2 = new ThreadCase2(); t1.start(); t2.start();