使用 gomail
先下载gomail 包

go get gopkg.in/gomail.v2

代码：

package main

import (
        "fmt"
        "gopkg.in/gomail.v2"
        "log"
        "strconv"
)

const (
        SMTPHost     = "smtp.qiye.aliyun.com"
        SMTPPort     = "465"  //25
        SMTPUsername = "xxx@x.com"
        SMTPPassword = "xxxx"
)


func SendMail(mailTo []string, subject string, body string) error {
        // 设置邮箱主体
        mailConn := map[string]string{
                "user": SMTPUsername,
                "pass": SMTPPassword,
                "host": SMTPHost,
                "port": SMTPPort,
        }

        port, _ := strconv.Atoi(mailConn["port"])
        m := gomail.NewMessage()
        m.SetHeader("From", m.FormatAddress(mailConn["user"], "银众网"))                   // 添加别名
        m.SetHeader("To", mailTo...)                                                      // 发送给用户(可以多个)
        m.SetHeader("Subject", subject)                                                   // 设置邮件主题
        m.SetBody("text/html", body)                                                      // 设置邮件正文
        d := gomail.NewDialer(mailConn["host"], port, mailConn["user"], mailConn["pass"]) // 设置邮件正文
        err := d.DialAndSend(m)
        return err
}

func main() {
        // 发送方
        mailTo := []string{
                "xxx", // 这里最好写成邮箱收发件时的这种标记格式
        }
        // 邮件主题
        subject := "Hello"
        // 邮件正文
        body := "Automatic send by Go gomail from xxx官方."
        err := SendMail(mailTo, subject, body)
        if err != nil {
                log.Print(err)
                fmt.Printf("Send fail!")
                return
        }
        fmt.Println("send successfully!")
}