转/articles/2098
核心代码：smtp.SendMail(host, auth, user, send_to, msg)，auth := smtp.PlainAuth("", user, password, hp[0])
可行方案：使用企业邮箱的SMTP发送邮件，host :="smtp.:25"，因此需要一个企业邮箱的账号和密码
直接上代码：
main.gopackagemainimport("fmt""net/smtp""strings")funcSendToMail(user,password,host,to,subject,body,mailtypestring)error{hp:=strings.Split(host,":")auth:=smtp.PlainAuth("",user,password,hp[0])varcontent_typestringifmailtype=="html"{content_type="Content-Type:text/"+mailtype+";charset=UTF-8"}else{content_type="Content-Type:text/plain"+";charset=UTF-8"}msg:=[]byte("To:"+to+"\r\nFrom:"+user+">\r\nSubject:"+"\r\n"+content_type+"\r\n\r\n"+body)send_to:=strings.Split(to,";")err:=smtp.SendMail(host,auth,user,send_to,msg)returnerr}funcmain(){user:="yang**@yun*.com"password:="***"host:="smtp.:25"to:="397685131@"subject:="使用Golang发送邮件"body:=`<html><body><h3>"Testsendtoemail"</h3></body></html>`fmt.Println("sendemail")err:=SendToMail(user,password,host,to,subject,body,"html")iferr!=nil{fmt.Println("Sendmailerror!")fmt.Println(err)}else{fmt.Println("Sendmailsuccess!")}}
遇到的问题：
1、body ：= ``，这里用的是反单引号，而非单引号；
2、err != nil，golang的nil在概念上和其它语言的null、None、nil、NULL一样，都指代零值或空值。nil是预先说明的标识符，也即通常意义上的关键字。在golang中，nil只能赋值给指针、channel、func、interface、map或slice类型的变量。如果未遵循这个规则，则会引发panic。对此官方有明确的说明：/pkg/builtin/#Type
3、参数auth，auth := smtp.PlainAuth("", user, password, hp[0])
4、强制类型转换，msg := []byte("To: " + to + "\r\nFrom: " + user + ">\r\nSubject: " + "\r\n" + content_type + "\r\n\r\n" + body)
5、多个邮箱：send_to := strings.Split(to, ";")
带附件方法2
package mainimport ("net/smtp""bytes""time""io/ioutil""encoding/base64""strings""log")// define email interface, and implemented auth and send methodtype Mail interface {Auth()Send(message Message) error}type SendMail struct {userstringpassword stringhoststringportstringauthsmtp.Auth}type Attachment struct {name stringcontentType stringwithFile bool}type Message struct {from stringto[]stringcc[]stringbcc []stringsubjectstringbody stringcontentType stringattachment Attachment}func main() {var mail Mailmail = &SendMail{user: "chunyunzeng@", password: "password", host: "", port: "25"}message := Message{from: "chunyunzeng@",to: []string{"850808158@"},cc: []string{},bcc: []string{},subject: "HELLO WORLD",body: "",contentType: "text/plain;charset=utf-8",attachment: Attachment{name: "test.jpg",contentType: "image/jpg",withFile: true,},}mail.Send(message)}func (mail *SendMail) Auth() {mail.auth = smtp.PlainAuth("", mail.user, mail.password, mail.host)}func (mail SendMail) Send(message Message) error {mail.Auth()buffer := bytes.NewBuffer(nil)boundary := "GoBoundary"Header := make(map[string]string)Header["From"] = message.fromHeader["To"] = strings.Join(message.to, ";")Header["Cc"] = strings.Join(, ";")Header["Bcc"] = strings.Join(message.bcc, ";")Header["Subject"] = message.subjectHeader["Content-Type"] = "multipart/mixed;boundary=" + boundaryHeader["Mime-Version"] = "1.0"Header["Date"] = time.Now().String()mail.writeHeader(buffer, Header)body := "\r\n--" + boundary + "\r\n"body += "Content-Type:" + message.contentType + "\r\n"body += "\r\n" + message.body + "\r\n"buffer.WriteString(body)if message.attachment.withFile {attachment := "\r\n--" + boundary + "\r\n"attachment += "Content-Transfer-Encoding:base64\r\n"attachment += "Content-Disposition:attachment\r\n"attachment += "Content-Type:" + message.attachment.contentType + ";name=\"" + message.attachment.name + "\"\r\n"buffer.WriteString(attachment)defer func() {if err := recover(); err != nil {log.Fatalln(err)}}()mail.writeFile(buffer, message.attachment.name)}buffer.WriteString("\r\n--" + boundary + "--")smtp.SendMail(mail.host+":"+mail.port, mail.auth, message.from, message.to, buffer.Bytes())return nil}func (mail SendMail) writeHeader(buffer *bytes.Buffer, Header map[string]string) string {header := ""for key, value := range Header {header += key + ":" + value + "\r\n"}header += "\r\n"buffer.WriteString(header)return header}// read and write the file to bufferfunc (mail SendMail) writeFile(buffer *bytes.Buffer, fileName string) {file, err := ioutil.ReadFile(fileName)if err != nil {panic(err.Error())}payload := make([]byte, base64.StdEncoding.EncodedLen(len(file)))base64.StdEncoding.Encode(payload, file)buffer.WriteString("\r\n")for index, line := 0, len(payload); index < line; index++ {buffer.WriteByte(payload[index])if (index+1)%76 == 0 {buffer.WriteString("\r\n")}}}
