[go-每日一库] golang中base64 md5 sha256的编解码及摘要算法

见代码：

package main

import (
	"crypto/md5"
	"crypto/sha256"
	"encoding/base64"
	"encoding/hex"
	"fmt"
	"io"
)

func main()  {
	var str string = "hello world"
	// md5
	// 1.md5V1
	h1 := md5.New()
	h1.Write([]byte(str))
	md5V1 := hex.EncodeToString(h1.Sum(nil))
	fmt.Printf("md5V1: %s\n", md5V1)
	// 2.md5V2
	h2 := md5.Sum([]byte(str))
	md5V2 := fmt.Sprintf("%x", h2)
	fmt.Printf("md5V2: %s\n", md5V2)
	// 3.md5V3
	h3 := md5.New()
	io.WriteString(h3, str)
	md5V3 := fmt.Sprintf("%x", h3.Sum(nil))
	fmt.Printf("md5V2: %s\n", md5V3)
	/*
	md5V1: 5eb63bbbe01eeed093cb22bb8f5acdc3
	md5V2: 5eb63bbbe01eeed093cb22bb8f5acdc3
	md5V2: 5eb63bbbe01eeed093cb22bb8f5acdc3
	*/

	// sha256
	// 1.sha256V1
	s1 := sha256.New()
	s1.Write([]byte(str))
	sha256v1 := hex.EncodeToString(s1.Sum(nil))
	fmt.Printf("sha256v1: %s\n", sha256v1)
	// 2.sha256V2
	s2 := sha256.Sum256([]byte(str))
	sha256V2 := fmt.Sprintf("%x", s2)
	fmt.Printf("sha256v2: %s\n", sha256V2)
	// 3.sha256V3
	s3 := sha256.New()
	s3.Write([]byte(str))
	sha256V3 := fmt.Sprintf("%x", s3.Sum(nil))
	fmt.Printf("sha256v3: %s\n", sha256V3)
	/*
	sha256v1: b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9
	sha256v2: b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9
	sha256v3: b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9
	*/

	// base64
	// encode
	encodeStr := base64.StdEncoding.EncodeToString([]byte(str))
	fmt.Printf("base64 encode: %s\n", encodeStr)
	// decode
	decodeStr, err := base64.StdEncoding.DecodeString(encodeStr)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Printf("base64 decode: %s\n", decodeStr)
	/*
	base64 encode: aGVsbG8gd29ybGQ=
	base64 decode: hello world
	 */
	// uriencode -> 把“/”换成“_”，把“+”换成“-”
	uriEncode := base64.URLEncoding.EncodeToString([]byte(str))
	fmt.Printf("base64 uriencode: %s\n", uriEncode)
	uriDecode, err := base64.URLEncoding.DecodeString(uriEncode)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Printf("base64 uridecode: %s\n", uriDecode)
	/*
	base64 uriencode: aGVsbG8gd29ybGQ=
	base64 uridecode: hello world
	*/
}