//获取随机字符串
func GetRandString(length int) string {
	if length < 1 {
		return ""
	}
	char := "abcdefghijklmnopqrstuvwsyzABCDEFGHIJKLMNOPQRSTUVWSYZ0123456789"
	charArr := strings.Split(char, "")
	//fmt.Println(charArr)
	charlen := len(charArr)

	b := rand.New(rand.NewSource(time.Now().Unix()))
	//fmt.Println(b)
	str := ""
	for i := 1; i <= length; i++ {
		r := b.Intn(charlen)
		str = str + charArr[r]
	}
	return str
}
