不重复编码生成工具类

import java.util.Random; public class IDUtils {public static String genImageName() {//取当前时间的长整形值包含毫秒long millis = System.currentTimeMillis();//long millis = System.nanoTime();//加上三位随机数Random random = new Random();int end3 = random.nextInt(999);//如果不足三位前面补0String str = millis + String.format("%03d", end3);return str;}public static long genItemId() {//取当前时间的长整形值包含毫秒long millis = System.currentTimeMillis();//long millis = System.nanoTime();//加上两位随机数Random random = new Random();int end2 = random.nextInt(99);//如果不足两位前面补0String str = millis + String.format("%02d", end2);long id = new Long(str);return id;}public static void main(String[] args) {for(int i=0;i< 100;i++)System.out.println(genItemId());}}