使用ConcurrentHashMap保证线程安全性，唯一性，AtomicInteger实现自增长

迷南。 2022-12-05 04:57 132阅读 0赞

## 情景：需要生成17位代码来代替UUid，前3位固定，后五位使用 AtomicInteger实现自增长，中间9为是截取当前时间的年月日时分秒 ##

## 自定义的DateUtil工具类： ##

```java
    
    
    import lombok.extern.slf4j.Slf4j;
    
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.util.Calendar;
    import java.util.Date;
    
    /**
     * Created by babata on 2014/12/25.
     */
    @Slf4j
    public class DateUtil {
        public static final String timeFormate = "yyyy-MM-dd HH:mm:ss";
        public static final String dateFormate = "yyyy-MM-dd";
        public static final String pannelTime = "yyyyMMddHHmmss";
        public static final String yyyyMMdd = "yyyyMMdd";
        public static final String HHMMSS = "HH:mm:ss";
        /**
         * 获取系统时间 年月日时分秒
         * @return
         */
        public static String nowDateTime(){
            SimpleDateFormat sdf = new SimpleDateFormat(timeFormate);
            Date date = new Date();
            return sdf.format(date);
        }
    
        public static String nowDay(){
            SimpleDateFormat sdf = new SimpleDateFormat(yyyyMMdd);
            Date date = new Date();
            return sdf.format(date);
        }
    
    
    
        public static long getDistaceLong(String dateStr) {
            try {
                SimpleDateFormat sdf = new SimpleDateFormat(timeFormate);
                Date date = sdf.parse(dateStr);
                return new Date().getTime() - date.getTime();
            }catch (Exception e){
                log.error("getDistaceLong error", e);
            }
    
            return 0;
        }
    
        public static String nowPannelDateTime(){
            SimpleDateFormat sdf = new SimpleDateFormat(pannelTime);
            Date date = new Date();
            return sdf.format(date);
        }
    
    
        public static Long nowDateTimeLong() {
            return new Date().getTime() ;
        }
        public static long time2Long(String time) {
            SimpleDateFormat sdf = new SimpleDateFormat(timeFormate);
            Date date = null;
            try {
                date = sdf.parse(time);
            } catch (ParseException e) {
                log.error("exe error", e);
            }
            return date.getTime();
        }
    
        /**
         * 年月日
         * @return
         */
        public static String yyyyMMdd(){
            SimpleDateFormat sdf = new SimpleDateFormat(yyyyMMdd);
            Date date = new Date();
            return sdf.format(date);
        }
    
        public static String nowDateTimeSimple(){
            SimpleDateFormat sdf = new SimpleDateFormat(dateFormate);
            Date date = new Date();
            return sdf.format(date);
        }
    
        public static String getNowHour(){
            SimpleDateFormat sdf = new SimpleDateFormat("HH");
            Date date = new Date();
            return sdf.format(date);
        }
    
        public static String getNowYear(){
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy");
            Date date = new Date();
            return sdf.format(date);
        }
        public static String getNowMonth(){
            SimpleDateFormat sdf = new SimpleDateFormat("MM");
            Date date = new Date();
            return sdf.format(date);
        }
        public static String getNowDD(){
            SimpleDateFormat sdf = new SimpleDateFormat("dd");
            Date date = new Date();
            return sdf.format(date);
        }
    
        public static int[] getWeekNum(String time) throws ParseException {
            SimpleDateFormat sdf = new SimpleDateFormat(dateFormate);
            Calendar cl = Calendar.getInstance();
            cl.setTime(sdf.parse(time));
            int week = cl.get(Calendar.WEEK_OF_YEAR);
            int year = cl.get(Calendar.YEAR);
            if(week<cl.get(Calendar.WEEK_OF_YEAR)){
                year+=1;
            }
    
            return new int[]{year,week};
        }
    
        public static Date parse2Date (String time,String fomate) throws ParseException {
            SimpleDateFormat sdf = new SimpleDateFormat(fomate);
            Date date = sdf.parse(time);
            return date;
        }
    
        public static String date2Str (Date date,String fomate) {
            SimpleDateFormat sdf = new SimpleDateFormat(fomate);
            return sdf.format(date);
        }
    
        public static Date parse2Date (String time) throws ParseException {
            SimpleDateFormat sdf = new SimpleDateFormat(timeFormate);
            Date date = sdf.parse(time);
            return date;
        }
    
    
        public static String date2Str(Date date) {
            SimpleDateFormat sdf = new SimpleDateFormat(timeFormate);
            return sdf.format(date);
        }
    
    
    
        public static String date2Str (long date,String fomate) {
            SimpleDateFormat sdf = new SimpleDateFormat(fomate);
            return sdf.format(date);
        }
    
        public static String date2Str(Long ms) {
            Integer ss = 1000;
            Integer mi = ss * 60;
            Integer hh = mi * 60;
            Integer dd = hh * 24;
    
            Long day = ms / dd;
            Long hour = (ms - day * dd) / hh;
            Long minute = (ms - day * dd - hour * hh) / mi;
            Long second = (ms - day * dd - hour * hh - minute * mi) / ss;
            Long milliSecond = ms - day * dd - hour * hh - minute * mi - second * ss;
    
            StringBuffer sb = new StringBuffer();
            if(day > 0) {
                sb.append(day+"天");
            }
    
            if(hour > 0) {
                sb.append(hour+"小时");
            }
            if(minute > 0) {
                sb.append(minute+"分");
            }
            if(second > 0) {
                sb.append(second+"秒");
            }
    
    
    //        if(milliSecond > 0) {
    //            sb.append(milliSecond+"毫秒");
    //        }
            return  String.valueOf(day * 24 + hour);
        }
    
        public static String oneHourAgo(){
            Calendar calendar = Calendar.getInstance();
            /* HOUR_OF_DAY 指示一天中的小时 */
            calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY) - 1);
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            return df.format(calendar.getTime());
    
        }
        public static String oneMonthAgo(){
            Calendar calendar = Calendar.getInstance();
            /* HOUR_OF_DAY 指示一天中的小时 */
            calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) - 1);
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            return df.format(calendar.getTime());
    
        }
    
        public static String getLastWeekStart(){
            Calendar date=Calendar.getInstance();
            date.setFirstDayOfWeek(Calendar.SUNDAY);//将每周第一天设为星期一，默认是星期天
            date.add(Calendar.WEEK_OF_MONTH,-1);//周数减一，即上周
            date.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);//日子设为星期天
            return date2Str(date.getTime(),dateFormate) + " 00:00:00";
        }
    
        public static String getLastWeekEnd(){
            Calendar date=Calendar.getInstance();
            date.setFirstDayOfWeek(Calendar.SUNDAY);//将每周第一天设为星期一，默认是星期天
            date.add(Calendar.WEEK_OF_MONTH,-1);//周数减一，即上周
            date.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);//日子设为星期天
            return date2Str(date.getTime(),dateFormate) + " 23:59:59";
        }
    
    
        public static void main(String[] args) {
            System.out.printf(oneMonthAgo());
        }
    
    
    
    
    }

## 具体代码实现： ##

package com.sdqj.system_integration.utils;
    
    import org.springframework.stereotype.Component;
    
    
    import java.util.Date;
    import java.util.concurrent.ConcurrentHashMap;
    import java.util.concurrent.atomic.AtomicInteger;
    @Component
    public class DeviceCodeGenrateUtil{ 
    //固定字符串头部
        private static final String HUNAN_PREFIX = "16M";
    //使用ConcurrentHashMap保证线程安全性，唯一性，AtomicInteger实现自增长
        public static ConcurrentHashMap<String, AtomicInteger> deviceCodeMap = new ConcurrentHashMap<String, AtomicInteger>();
    
        public synchronized   String CreateDeviceCode() { 
    //规定日期格式，
            String date = DateUtil.date2Str(new Date(),DateUtil.pannelTime);
            //截取其2-11位
            date = date.substring(2, 11);
            //将固定头和截取的日期拼接起来
            String codeKey = HUNAN_PREFIX + date;
    
            AtomicInteger intNextCrtID = deviceCodeMap.get(codeKey);
            if(intNextCrtID == null) { 
                intNextCrtID  = new AtomicInteger(1);
                deviceCodeMap.put(codeKey, new AtomicInteger());
            }
            //自增
            int index = intNextCrtID.getAndIncrement();
            String indexStr = "00000".substring(0, 5-(index + "").length()) + index;
    
            //拼接17位字符串
            return codeKey + indexStr;
        }
    
    
    
    }