Java中sleep()与wait()的区别总结

/**
 * 
 */
package com.b510.test;

/**
 * java中的sleep()和wait()的区别
 * @author Hongten
 * @date 2013-12-10
 */
public class TestD {

 public static void main(String[] args) {
  new Thread(new Thread1()).start();
  try {
   Thread.sleep(5000);
  } catch (Exception e) {
   e.printStackTrace();
  }
  new Thread(new Thread2()).start();
 }
 
 private static class Thread1 implements Runnable{
  @Override
  public void run(){
   synchronized (TestD.class) {
   System.out.println("enter thread1..."); 
   System.out.println("thread1 is waiting...");
   try {
    //调用wait()方法，线程会放弃对象锁，进入等待此对象的等待锁定池
    TestD.class.wait();
   } catch (Exception e) {
    e.printStackTrace();
   }
   System.out.println("thread1 is going on ....");
   System.out.println("thread1 is over!!!");
   }
  }
 }
 
 private static class Thread2 implements Runnable{
  @Override
  public void run(){
   synchronized (TestD.class) {
    System.out.println("enter thread2....");
    System.out.println("thread2 is sleep....");
    //只有针对此对象调用notify()方法后本线程才进入对象锁定池准备获取对象锁进入运行状态。
    TestD.class.notify();
    //==================
    //区别
    //如果我们把代码：TestD.class.notify();给注释掉，即TestD.class调用了wait()方法，但是没有调用notify()
    //方法，则线程永远处于挂起状态。
    try {
     //sleep()方法导致了程序暂停执行指定的时间，让出cpu该其他线程，
     //但是他的监控状态依然保持者，当指定的时间到了又会自动恢复运行状态。
     //在调用sleep()方法的过程中，线程不会释放对象锁。
     Thread.sleep(5000);
    } catch (Exception e) {
     e.printStackTrace();
    }
    System.out.println("thread2 is going on....");
    System.out.println("thread2 is over!!!");
   }
  }
 }
}

enter thread1...
thread1 is waiting...
enter thread2....
thread2 is sleep....
thread2 is going on....
thread2 is over!!!
thread1 is going on ....
thread1 is over!!!

TestD.class.notify();

enter thread1...
thread1 is waiting...
enter thread2....
thread2 is sleep....
thread2 is going on....
thread2 is over!!!