zoukankan      html  css  js  c++  java
  • Java线程同步锁的选择

      在需要线程同步的时候如何选择合适的线程锁?

    例:选择可以存入到常量池当中的对象,String对象等  

    public class SyncTest
    {
        private String name = "name";
    public void method(String flag)
        {
            synchronized (name)
            {
                System.out.println(flag + ", invoke method ....");
                try
                {
                    Thread.sleep(1000);
                }
                catch (InterruptedException e)
                {
                    e.printStackTrace();
                }
            }
        }
        
        public static void main(String[] args)
        {
            SyncTest test1 = new SyncTest();
            
            SyncTest test2 = new SyncTest();
            
            MyThread1 myThread1 = new MyThread1();
            MyThread1 myThread2 = new MyThread1();
            myThread1.syncTest = test1;
            myThread2.syncTest = test1; 
            
            MyThread1 myThread3 = new MyThread1();
            MyThread1 myThread4 = new MyThread1();
            myThread3.syncTest = test2;
            myThread4.syncTest = test2;
            
            myThread1.start();
            myThread2.start();
            myThread3.start();
            myThread4.start();
            
        }
    
    
    }


    线程类:

    public class MyThread1 extends Thread
    {
        SyncTest syncTest;
        
        @Override
        public void run()
        {
            syncTest.method(this.getName());
        }
    
    }

    本来应该是要实现线程thread1和thread2同步,线程thread3和thread4同步的,但结果呢?

    却是使得线程thread1、thread2、thread3、thread4同步了,很是郁闷。

    我推荐选用的同步锁对象:

    package com.rcx.thread;
    
    
    public class SyncTest
    {
        // 特殊的instance变量,用于充当同步锁的对象
        private byte[] lock = new byte[0];
        
        public void method(String flag)
        {
            synchronized (lock)
            {
                System.out.println(flag + ", invoke method f....");
                try
                {
                    Thread.sleep(1000);
                }
                catch (InterruptedException e)
                {
                    e.printStackTrace();
                }
            }
        }
        
        public static void main(String[] args)
        {
            SyncTest test1 = new SyncTest();
            
            SyncTest test2 = new SyncTest();
            
            MyThread1 myThread1 = new MyThread1();
            MyThread1 myThread2 = new MyThread1();
            myThread1.syncTest = test1;
            myThread2.syncTest = test1; 
            
            MyThread1 myThread3 = new MyThread1();
            MyThread1 myThread4 = new MyThread1();
            myThread3.syncTest = test2;
            myThread4.syncTest = test2;
            
            myThread1.start();
            myThread2.start();
            myThread3.start();
            myThread4.start();
            
        }
    
    
    }

    推荐使用0长度的byte数组充当同步锁对象,不会产生很诧异的错误同时不会占用很大内存。

  • 相关阅读:
    DateTime 格式化示例
    Linq To XML概述[转]
    .net邮件发送代码
    ASP.NET中c#的URL编码处理
    消息队列(Message Queue)简介及其使用
    C#多线程学习笔记之(abort与join配合使用)
    异常处理的性能损失
    推荐一款DataGridView的打印解决方案
    玩转App.Config
    推荐一个快速反射调用的类
  • 原文地址:https://www.cnblogs.com/renchunxiao/p/3079850.html
Copyright © 2011-2022 走看看