GO语言 短URL生成

短URL介绍链接：
1）https://segmentfault.com/a/1190000012088345
2）http://www.voidcn.com/article/p-ydjqllgt-ed.html
3）https://pathbox.github.io/2018/02/22/short-url-build-system/

开始撸代码：

package main

import (
    "crypto/md5"
    "fmt"
    "strconv"
    "strings"
)
var chars = strings.Split("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789", "")

// 1) 哈希实现
func hashShortUrl(url string) {
    hex := fmt.Sprintf("%x", md5.Sum([]byte(url)))
    resUrl := make([]string, 4)
    for i := 0;i < 4;i++ {
        val, _ := strconv.ParseInt(hex[i*8:i*8+8], 16, 0)
        lHexLong := val & 0x3fffffff
        outChars := ""
        for j := 0;j < 6;j++ {
            outChars += chars[0x0000003D & lHexLong]
            lHexLong >>= 5
        }
        resUrl[i] = outChars
    }
    fmt.Println(resUrl)
}

// 2) 自增长算法
func autoShortUrl(id int64) string {
    return GetString62(Encode62(id))
}

func Encode62(id int64) []int64 {
    tempE := []int64{}

    for id > 0 {
        tempE = append(tempE, id % 62)
        id /= 62
    }
    return tempE
}

func GetString62(indexA []int64) string {
    res := ""

    for _, val := range indexA {
        res += chars[val]
    }
    return reverseString(res)
}

// 反转字符串
func reverseString(s string) string {
    runes := []rune(s)
    for from, to := 0, len(runes) - 1;from < to;from, to = from + 1, to - 1 {
        runes[from], runes[to] = runes[to], runes[from]
    }
    return string(runes)
}

func main()  {
    fmt.Println(autoShortUrl(123))
}