JAVA多线程中的synchronized怎么用？

[码农StayUp]

我只知道它有synchronized 方法和 synchronized 块
但不知道他们到底怎么用，他们的操作对象是什么？

[cweijiaweil]

1.synchronized方法
class Demo implements Runnable
{
private int ticket = 10 ;
// 加入一个同步方法
public synchronized void fun()
{
// 把需要同步的地方放在同步方法之中
if(this.ticket>0)
{
try
{
Thread.sleep(100) ;
}
catch (Exception e)
{
}
System.out.println(Thread.currentThread().getName()+" --> 卖票："+this.ticket--) ;
}
}
public void run()
{
while(ticket>0)
{
this.fun() ;
}
}
};
public class ThreadDemo14
{
public static void main(String args[])
{
Demo d = new Demo() ;
Thread t1 = new Thread(d,"售票点 A") ;
Thread t2 = new Thread(d,"售票点 B") ;
Thread t3 = new Thread(d,"售票点 C") ;

t1.start() ;
t2.start() ;
t3.start() ;
}
};

2.synchronized同步块
class Demo implements Runnable
{
private int ticket = 10 ;
public void run()
{
while(ticket>0)
{
// 加入同步块
synchronized(this)
{
if(this.ticket>0)
{
try
{
Thread.sleep(100) ;
}
catch (Exception e)
{
}
System.out.println(Thread.currentThread().getName()+" --> 卖票："+this.ticket--) ;
}
}
}
}
};
public class ThreadDemo15
{
public static void main(String args[])
{
Demo d = new Demo() ;
Thread t1 = new Thread(d,"售票点 A") ;
Thread t2 = new Thread(d,"售票点 B") ;
Thread t3 = new Thread(d,"售票点 C") ;

t1.start() ;
t2.start() ;
t3.start() ;
}
};

[lulu0126]

楼主怎么没有结过贴！

synchronized 修饰的部分 简单理解就是独自占有！

它用完了，别人才能用！

这个很好用的，随便找个代码给你吧！马士兵教程中有一个

public class TestSycronized implements Runnable{
	
int b = 100;

public synchronized void m1() throws Exception{
	
	b =1000;
	
	Thread.sleep(5000);
	
	System.out.println("b ="+b);
	
	
} 

public void m2(){
System.out.println(b);
		
	}
public synchronized  void run(){
	
	try{
		
		m1();
	}catch (Exception e){
		
		e.printStackTrace();
		
	}
	
	
}	
public static void main(String[] args) throws Exception{
	
	TestSycronized ts= new TestSycronized();
	
	Thread t =new Thread(ts) ;
	
	t.start();
	Thread.sleep(1000);
	
	ts.m2();
}

		
		
	}