多线程中，java锁的应用

╰+攻爆jí腚メ 2022-07-31 16:26 106阅读 0赞

6.11去面试，谈到多线程如何保证数据先后顺序

http://www.blogjava.net/tscfengkui/archive/2010/11/10/337709.html?opt=admin

锁住一个方法，

package com.dr.runnable2;
    class TicketSouce implements Runnable
    {
        //票的总数
        private int ticket=10;
        public void run()
        {
            for(int i=1;i<50;i++)
            {
                try {
                    //休眠1s秒中，为了使效果更明显，否则可能出不了效果
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                this.sale();
            }
        }
        public synchronized void sale()
        {
                if(ticket>0)
                {
                    System.out.println(Thread.currentThread().getName()+"号窗口卖出"+this.ticket--+"号票");
                }
        }
    }
    public class Test {
        public static void main(String args[])
        {
            TicketSouce mt=new TicketSouce();
            //基于火车票创建三个窗口
            new Thread(mt,"a").start();
            new Thread(mt,"b").start();
            new Thread(mt,"c").start();
        } 
    
    }

锁住自身对象：

package com.dr.runnable2;
    class TicketSouce implements Runnable
    {
        //票的总数
        private int ticket=10;
        public void run()
        {
            for(int i=1;i<50;i++)
            {
                synchronized(this){
                    if(ticket>0)
                    {
                        //休眠1s秒中，为了使效果更明显，否则可能出不了效果
                        try {
                            Thread.sleep(1000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        System.out.println(Thread.currentThread().getName()+"号窗口卖出"+this.ticket--+"号票");
                    }
                                  }
            }
        }
    }
    public class Test {
        public static void main(String args[])
        {
            TicketSouce mt=new TicketSouce();
            //基于火车票创建三个窗口
            new Thread(mt,"a").start();
            new Thread(mt,"b").start();
            new Thread(mt,"c").start();
        } 
    
    }

自己写了一个对象锁来测试

public class LockTest {
    	public static void main(String[] args) {
    		Object ob = new Object();
    		for (int i = 0; i < 20; i++) {
    			(new mThread(ob,"this is " + i)).start();
    		}
    	}
    	
    	
    }
    
    class mThread extends Thread {
    	private Object locker;
    	private String text;
    	public mThread (Object locker,String text) {
    		this.locker=locker;
    		this.text = text;
    	}
    	@Override
    	public void run() {
    		synchronized(locker) {
    			 //休眠1s秒中，为了使效果更明显，否则可能出不了效果
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
    			System.out.println(text);
    		}
    	}
    }

运行结果：

this is 0

this is 19

this is 18

this is 17

this is 16

this is 15

this is 14

this is 13

this is 12

this is 11

this is 10