golang生成定单号的操作

//生成单号
//06123xxxxx
//sum 最少10位,sum 表示全部单号位数
func MakeYearDaysRand(sum int) string {
  //年
  strs := time.Now().Format("06")
  //一年中的第几天
  days := strconv.Itoa(GetDaysInYearByThisYear())
  count := len(days)
  if count <3 {
    //重复字符0
    days = strings.Repeat("0", 3-count) + days
  }
  //组合
  strs += days
  //剩余随机数
  sum = sum - 5
  if sum <1 {
    sum = 5
  }
  //0~9999999的随机数
  ran := GetRand()
  pow := math.Pow(10, float64(sum)) - 1
  //fmt.Println("sum=>", sum)
  //fmt.Println("pow=>", pow)
  result := strconv.Itoa(ran.Intn(int(pow)))
  count = len(result)
  //fmt.Println("result=>", result)
  if count  2 {
    total = total + d + 1
  } else {
    total = total + d
  }
  return total;
}

package ordernum 
import (
  "fmt"
  "github.com/w3liu/go-common/constant/timeformat"
  "os"
  "sync/atomic"
  "time"
)
 
var num int64 
//生成24位订单号
//前面17位代表时间精确到毫秒，中间3位代表进程id，最后4位代表序号
func Generate(t time.Time) string {
  s := t.Format(timeformat.Continuity)
  m := t.UnixNano()/1e6 - t.UnixNano()/1e9*1e3
  ms := sup(m, 3)
  p := os.Getpid() % 1000
  ps := sup(int64(p), 3)
  i := atomic.AddInt64(&num, 1)
  r := i % 10000
  rs := sup(r, 4)
  n := fmt.Sprintf("%s%s%s%s", s, ms, ps, rs)
  return n
}
 
//对长度不足n的数字前面补0
func sup(i int64, n int) string {
  m := fmt.Sprintf("%d", i)
  for len(m)