} } }

    Java线程同步锁的选择

    添加时间:2013-5-15 点击量:

      在须要线程同步的时辰如何选择合适的线程锁?


    例:选择可以存入到常量池傍边的对象,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());
    }

    }


    底本应当是要实现线程thread1和thread2同步,线程thread3和thread4同步的,但成果呢?


    倒是使得线程thread1、thread2、thread3、thread4同步了,很是愁闷。


    我推荐选用的同步锁对象:



    package com.rcx.thread;
    


    public class SyncTest
    {
    // 特别的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();

    }


    }


    推荐应用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。


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