java的ThreadLocal类的使用方法

java的ThreadLocal类的使用方法，ThreadLocal是一个支持泛型的类，用在多线程中用于防止并发冲突问题。

比如以下的一个样例，就是用于线程添加1，可是相互不冲突

package com.test.threadlocal;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

class Local
{
	private static ThreadLocal<Integer> num=new ThreadLocal<Integer>()
			{
				protected synchronized Integer initialValue()
				{
					return 1;
				}
			};

	public static void add()
	{
		num.set(num.get()+1);
	}
	public static int get()
	{
		return num.get();
	}
}

class SelfThread extends Thread
{
	public void run()
	{
		for(int i=0;i<1000;i++)
		{
			System.out.println(this.getName()+"  "+Local.get());
			this.yield();
			Local.add();
		}
	}
}
public class MyThreadLocal {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ExecutorService exec=Executors.newCachedThreadPool();
		for(int i=0;i<5;i++)
		{
			exec.execute(new SelfThread());
		}

		exec.shutdown();
	}

}

输出结果

Thread-3  973

Thread-1  808

Thread-3  974

Thread-1  809

Thread-3  975

Thread-1  810

Thread-3  976

Thread-1  811

Thread-3  977

Thread-1  812

Thread-3  978

Thread-1  813

Thread-3  979

Thread-1  814

Thread-3  980

Thread-1  815

Thread-3  981

Thread-1  816

Thread-3  982

Thread-1  817

Thread-3  983

Thread-1  818

Thread-3  984

Thread-1  819

Thread-3  985

Thread-1  820

Thread-3  986

Thread-1  821

Thread-3  987

Thread-1  822

Thread-3  988

Thread-1  823

Thread-3  989

Thread-1  824

Thread-3  990

Thread-1  825

Thread-3  991

Thread-1  826

Thread-3  992

Thread-1  827

Thread-3  993

Thread-1  828

Thread-3  994

Thread-1  829

Thread-3  995

Thread-1  830

Thread-3  996

Thread-1  831

Thread-3  997

Thread-1  832

Thread-3  998

Thread-1  833

Thread-3  999

Thread-1  834

Thread-3  1000

Thread-1  835

Thread-1  836

Thread-1  837

Thread-1  838

Thread-1  839

Thread-1  840

Thread-1  841

Thread-1  842

Thread-1  843

Thread-1  844

Thread-1  845

Thread-1  846

Thread-1  847

Thread-1  848

Thread-1  849

Thread-1  850

Thread-1  851

Thread-1  852

Thread-1  853

Thread-1  854

Thread-1  855

Thread-1  856

Thread-1  857

Thread-1  858

Thread-1  859

Thread-1  860

Thread-1  861

Thread-1  862

Thread-1  863

Thread-1  864

Thread-1  865

Thread-1  866

Thread-1  867

Thread-1  868

Thread-1  869

Thread-1  870

Thread-1  871

Thread-1  872

Thread-1  873

Thread-1  874

我们发现。线程会相互切换，可是每一个线程都保持了添加1的顺序，说明没有线程之间的相互干扰。