生成订单编号的工具类

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package io.coderyeah.basic.util;

import java.math.BigDecimal;
import java.text.SimpleDateFormat;
import java.util.Calendar;


public class CodeGenerateUtils {
   
   /**
    * 获取商品编码
    * 商品编码规则：nanoTime(后5位)*5位随机数(10000~99999)
    * @return
    */
   public static String generateProductCode(){
      long nanoPart = System.nanoTime() % 100000L;
      if(nanoPart<10000L){
         nanoPart+=10000L;
      }
      long randomPart = (long)(Math.random()*(90000)+10000);
      String code = "0"+String.valueOf((new BigDecimal(nanoPart).multiply(new BigDecimal(randomPart))));
      return code.substring(code.length()-10);
   }
   
   /**
    * @param id: 用户id
    * 生成订单编号
    * 订单编号规则：(10位)：(年末尾*月，取后2位)+（用户ID%3.33*日取整后2位）+(timestamp*10000以内随机数，取后6位)
    * @return
    */
   public static String generateOrderSn(long id){
      Calendar calendar = Calendar.getInstance();
      int year = calendar.get(Calendar.YEAR);
      year = year % 10;
      if(year == 0) year = 10;
      int month = calendar.get(Calendar.MONTH)+1;
      int yearMonth  =  year * month;
      String yearMonthPart = "0"+yearMonth;
      yearMonthPart = yearMonthPart.substring(yearMonthPart.length() - 2 );
      
      int day = calendar.get(Calendar.DAY_OF_MONTH);
      int dayNum = (int)((id % 3.33) * day);
      String dayPart = "0"+dayNum;
      dayPart = dayPart.substring(dayPart.length() - 2);
      
      String timestampPart = ""+(Math.random() * 10000) * (System.currentTimeMillis()/10000);
      timestampPart = timestampPart.replace(".", "").replace("E", "");
      timestampPart = timestampPart.substring(0,6);
      return yearMonthPart+dayPart+timestampPart;
   }
   
   /**
    * 生成统一支付单号
    * 规则：年(2)月(2)日(2)时(2)分(2)+timestamp*5位随机整数取后5位
    * @return
    */
   public static String generateUnionPaySn(){
      Calendar calendar = Calendar.getInstance();
      SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddhhmm");
      String dateTime = dateFormat.format(calendar.getTime());
      dateTime = dateTime.substring(2);
      String timestampPart = ""+(Math.random() * 10000) * (System.currentTimeMillis()/10000);
      timestampPart = timestampPart.replace(".", "").replace("E", "");
      timestampPart = timestampPart.substring(0,5);
      return dateTime+timestampPart;
   }
   
   public static void main(String[] args) {
      for(long i=0;i<100;i++)
      {
         //String timestampPart = ""+(Math.random() * 10000) * (System.currentTimeMillis()/10000);
         //System.out.println(timestampPart);
         //System.out.println(generateOrderSn(i));
         System.out.println(generateUnionPaySn());
      }
   }
   
}