JAVA Synchronized 关键字锁实例和锁CLASS对象的区别

package Thread.synchronizedTest;

public class SynchronizedTest {
 
 /**
  * 锁住class对象
  */
 public static   void synchronizedStatic(){
  synchronized(SynchronizedTest.class){
   System.out.println("synchronizedStatic");
   try {
    Thread.sleep(10000);
   } catch (InterruptedException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   
  }
   
 }
 
 /**
  * 锁住方法，lock标记打在该实力上
  */
 public synchronized void synchronizedMethod(){
  System.out.println("synchronizedMethod");
  try {
   Thread.sleep(8000);
  } catch (InterruptedException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  
 }
 
 /**
  * 不会有影响，正常调用
  */
 public  void synchronizedMethod2WithNosynchronized(){
  System.out.println("synchronizedMethod2WithNosynchronized");
 }
 /**
  * synchronizedMethod 已经锁住实例，
  * 再加锁不成功
  */
 public  void synchronizedMethod2(){
  synchronized( this ){
   System.out.println("synchronizedMethod2");
   try {
   Thread.sleep(15000);
  } catch (InterruptedException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  }
 }
 
 /**
  * synchronizedMethod 已经锁住实例，
  * 再加锁不成功
  */ 
 public  void synchronizedMethod3(){
  synchronized( this ){
   System.out.println("synchronizedMethod3");
 } 

  
 }

 /**
  * @param args
  * @throws InterruptedException 
  */
 public static void main(String[] args) throws InterruptedException {
  // TODO Auto-generated method stub
  final SynchronizedTest t= new SynchronizedTest();
  Thread th = new Thread( new Runnable(){

   @Override
   public void run() {
    // TODO Auto-generated method stub
    t.synchronizedStatic();
   }
   
  } );
  th.start();
  
  
  th = new Thread( new Runnable(){

   @Override
   public void run() {
    // TODO Auto-generated method stub
    t.synchronizedMethod();
   }
   
   
  } );
  th.start();
  
  
 
  th = new Thread( new Runnable(){

   @Override
   public void run() {
    // TODO Auto-generated method stub
    t.synchronizedMethod2();
   }
   
   
  } );
  th.start();
  t.synchronizedMethod2WithNosynchronized();
  
  t.synchronizedMethod3();
 }

}

 

评论

1 楼 panamera 2017-09-05  

楼主有没有测试过，没有发你说什么锁不成功，都不知道你想表达什么。t.synchronizedMethod2WithNosynchronized();

t.synchronizedMethod3();都能正常执行，使用的锁都是类对象，没有毛病