JAVA多线程放号器

做一个放号器, 多个线程同时申请号码不重复,断电后能恢复.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

比如:

线程1 : 1, 4, 5, 6, 8, 9, 14…

线程2 : 2, 3, 7, 10, 11, 12, 13…

package org.leno.j2se.lesson3.multiThread;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.RandomAccessFile;

/**

* @author leno

* 一个简单的放号器, 多个线程同时申请号码不重复,断电后能恢复.

*/

public class SendCode implements Runnable{

//号码

int code = 0;

RandomAccessFile raf = null;

//初始化块

{

try {

raf = new RandomAccessFile("sendCode.txt","rw");

code = raf.readInt();

System.out.println("恢复上次记录："+code);

} catch (FileNotFoundException e) {

System.out.println("文件找不到！");

}catch (IOException e) {

System.out.println("没有合适的整数值");

}

}

public void run() {

while(true){

synchronized (this) {

try {

Thread.sleep(300);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

code++;

try {

raf.seek(0);//从文件开头以字节为单位测量的偏移量位置，在该位置设置文件指针

raf.writeInt(code);//从文件指针的当前位置开始写

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println(Thread.currentThread().getName()+"申请到号码："+code);

}

}

}

public static void main(String[] args) {

SendCode sc = new SendCode();

new Thread(sc,"一号线程").start();

new Thread(sc,"二号线程").start();

new Thread(sc,"三号线程").start();

new Thread(sc,"四号线程").start();

}

}