随机数按指定格式 写入文件

package com.heima.test;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Comparator;
import java.util.Random;
import java.util.TreeSet;

public class Test6 {

    /**随机数按指定格式 写入文件 * @param args * @throws IOException */
    public static void main(String[] args) throws IOException {
        Random num = new Random();
        FileWriter fos = new FileWriter("num.txt");
        TreeSet<Integer> ts = new TreeSet<Integer>(new Comparator<Integer>() {

            @Override
            public int compare(Integer o1, Integer o2) {
                int num = o2 - o1;
                return num ;
            }
        });
        while(ts.size() < 10){
            ts.add(num.nextInt(100) + 1);
        }
        System.out.println(ts);
        int i = 0;
        for (Integer integer : ts) {
            if(i == ts.size() - 1){
                fos.write(integer.toString());
            }else{
                fos.write(integer.toString()+",");
                i++;
            }
        }
        fos.close();        
    }
}