1、Java根据日期生成编号

根据日期生成编号

1、使用 DateTimeFormatter

DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyyMMddHHmmssSSS");//设置日期格式
String newsNo = "xw"+LocalDateTime.now().format(fmt);

2、使用 SimpleDateFormat

SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmss");//设置日期格式
String newsNo = "xw"+df.format(new Date());// new Date()为获取当前系统时间，也可使用当前时间戳

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Random;/*** @Desc:   * 订单编码码生成器，生成32位数字编码，* @生成规则 1位单号类型+17位时间戳+14位(用户id加密&随机数)*/public class OrderCoderUtil {/** 订单类别头 */private static final String ORDER_CODE = "1";/** 退货类别头 */private static final String RETURN_ORDER = "2";/** 退款类别头 */private static final String REFUND_ORDER = "3";/** 未付款重新支付别头 */private static final String AGAIN_ORDER = "4";/** 随即编码 */private static final int[] r = new int[]{7, 9, 6, 2, 8 , 1, 3, 0, 5, 4};/** 用户id和随机数总长度 */private static final int maxLength = 14;/*** 生成订单单号编码* @param userId*/public static String getOrderCode(Long userId){return ORDER_CODE + getCode(userId);}/*** 生成退货单号编码* @param userId*/public static String getReturnCode(Long userId){return RETURN_ORDER + getCode(userId);}/*** 生成退款单号编码* @param userId*/public static String getRefundCode(Long userId){return REFUND_ORDER + getCode(userId);}/*** 未付款重新支付* @param userId*/public static String getAgainCode(Long userId){return AGAIN_ORDER + getCode(userId);}/*** 更具id进行加密+加随机数组成固定长度编码*/private static String toCode(Long id) {String idStr = id.toString();StringBuilder idsbs = new StringBuilder();for (int i = idStr.length() - 1 ; i >= 0; i--) {idsbs.append(r[idStr.charAt(i)-'0']);}return idsbs.append(getRandom(maxLength - idStr.length())).toString();}/*** 生成时间戳*/private static String getDateTime(){DateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmssSSS");return sdf.format(new Date());}/*** 生成固定长度随机码* @param n    长度*/private static long getRandom(long n) {long min = 1,max = 9;for (int i = 1; i < n; i++) {min *= 10;max *= 10;}long rangeLong = (((long) (new Random().nextDouble() * (max - min)))) + min ;return rangeLong;}/*** 生成不带类别标头的编码* @param userId*/private static synchronized String getCode(Long userId){userId = userId == null ? 10000 : userId;return getDateTime() + toCode(userId);}}