Java 订单号生成

开发工具与关键技术：MyEclipse、java
作者：清晨
撰写时间：2019.5.28

package com.gx.serial;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.locks.ReentrantLock;

public class RandomNumber {
	// 使用单例模式，不允许直接创建实例
    private RandomNumber() {}
    // 创建一个空实例对象，类需要用的时候才赋值
    private static RandomNumber instance = null;
    // 单例模式--懒汉模式
    public static synchronized RandomNumber getInstance() {
        if (instance == null) {
        	instance = new RandomNumber();
        }
        return instance;
    }
    // 全局自增数
    private static int count = 1;
    // 格式化的时间字符串
    private static final SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
    // 获取当前时间年月日时分秒毫秒字符串
    private static String getNowDateStr() {
        return sdf.format(new Date());
    }
    // 记录上一次的时间，用来判断是否需要递增全局数
    private static String now = null;
    //定义锁对象
    private final static ReentrantLock lock=new ReentrantLock();
    //调用的方法
    public static String GetRandom(){
    	String Newnumber=null;
    	String dateStr=getNowDateStr();
    	lock.lock();//加锁
    	//判断是时间是否相同
    	if (dateStr.equals(now)) {
    		try {
       		 if (count >= 10000)
                {
                    count = 1;
                }
           	 if (count<10) {
           		 Newnumber = "N" + getNowDateStr()+"000"+count;
       		}else if (count<100) {
       			Newnumber = "N" + getNowDateStr()+"00"+count;
       		}else if(count<1000){
       			 Newnumber = "N" + getNowDateStr()+"0"+count;
       		}else  {
       			 Newnumber = "N" + getNowDateStr()+count;
       		}
                count++;
   		} catch (Exception e) {
   		}finally{
   			lock.unlock();
   		}
		}else{
			count=1;
			now =getNowDateStr();
			try {
				 if (count >= 10000)
	                {
	                    count = 1;
	                }
	           	 if (count<10) {
	           		 Newnumber = "N" + getNowDateStr()+"000"+count;
	       		}else if (count<100) {
	       			Newnumber = "N" + getNowDateStr()+"00"+count;
	       		}else if(count<1000){
	       			 Newnumber = "N" + getNowDateStr()+"0"+count;
	       		}else  {
	       			 Newnumber = "N" + getNowDateStr()+count;
	       		}
	                count++;
			} catch (Exception e) {
			}finally{
				lock.unlock();
			}
		}
         return Newnumber;//返回的值
    }
}

结果数据