java 生成訂單号

public class Order {

private static int orderNum = 0001;

public static String getOrderNo(){

long No = 0;

SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");

String nowdate = sdf.format(new Date());

No = Long.parseLong(nowdate)*10000;//這裡如果一天訂單多的話可以用一萬或更大

No+=getNo();

return getUserId()+No;

}

public static int getNo(){//傳回當天的訂單數+1

orderNum++;

return orderNum;

public static String getUserId(){

return "123";

public static String RandomStringId(){

UUID uuid = UUID.randomUUID();

return uuid.toString();