用文件实现一个计数器

package com.test;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;

public class Test {
	
	static int  num=0;

	/**
	 * @param args
	 */
	public static void main(String[] args)throws Exception {
		for(int i=0;i<100;i++){
			numTicket();
		}
	}

	/**
	 * <p>用文件实现一个计数器</p>
	 * @param array
	 * @return
	 */
	public synchronized static void numTicket()throws Exception {
		BufferedReader reader=new BufferedReader(new FileReader(new File("D:\\workspace\\Test\\src\\num.txt")));
		
		String nums=reader.readLine();
		reader.close();
		if(null!=nums&&!"".equals(nums))
			num=Integer.parseInt(nums);
		num++;
		BufferedWriter writer=new BufferedWriter(new FileWriter("D:\\workspace\\Test\\src\\num.txt"));
		writer.write(new Integer(num).toString());
		writer.flush();
		writer.close();
	}

}