1. Mail transfer protocol

Email needs to be transmitted between the mail client and the mail server as well as between two mail servers. Therefore, certain rules must be observed, which is the mail transfer protocol. Here are a few protocols:

1. SMTP: Short for Simple Mail Transfer Protocol. It defines the communication rules between the mail client software and the SMTP mail server, as well as between two SMTP mail servers.
2. POP3: Post Office Protocol. It defines the communication rules between mail client software and POP3 mail server.
3. The Internet Message Access Protocol (IMAP) is an extension of THE POP3 Protocol and defines the communication rules between the mail client software and the IMAP mail server.

2. Enable the SMTP service and obtain the authorization code

Here we take QQ mailbox as an example. In order to send QQ emails in SpringBoot, you must first turn on the SMTP function of QQ mailbox, which is disabled by default. Specific operations are as follows. Go to email → Settings → Accounts and find the one below

There’s a verification here

Once the validation is complete

3. Import dependency and configuration description

Here I’m using Gradle and introducing the spring-boot-starter-mail module

implementation group: 'org.springframework.boot', name: 'spring-boot-starter-mail', version: '2.4.10'
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Application. Yml configuration

Spring: mail: # host: smtp.qq.com # SMTP server port:587
    username: 1786087581@qqCom # here is the email authorization code, not the email login password # here is the email authorization code, I write the password: Properties: mail: SMTP: socketFactory:class: javax.net.ssl.SSLSocketFactory# #ssl: # #enable :true# set the message code toutf- 8 -default-encoding: utf- 8 -Copy the code

Supplement: 126 Email SMTP server ADDRESS :smtp.126.com, port number :465 or 994 2163 Email SMTP server address :smtp.163.com, port number :465 or 994 Yeah email SMTP server address :smtp.yeah.net, port number :465 or 994 QQ email SMTP server address: smtp.qq.com, port number :465 or 587*

4. Email sending

4.1 Sending Simple Emails

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import java.io.File;
import java.util.Date;
import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.FileSystemResource;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@api (value = "email interface ",tags =" email interface ",description = "email interface ")
@RequestMapping("/mail")
public class SendMailController {

@Autowired 
JavaMailSender javaMailSender;

@GetMapping("/sendMail")
public void sendMail(a){
    // Build a mail object
    SimpleMailMessage message = new SimpleMailMessage();
    // Set the email subject
    message.setSubject("This is a test email.");
    // Set the sender of the message
    message.setFrom("[email protected]");
    // Set the mail recipient. You can have multiple recipients
    message.setTo("1******[email protected]"."1*******[email protected]");
    // Set email cc recipients
    message.setCc("6666***[email protected]");
    // Set up a private cc person
    message.setBcc("l*****[email protected]");
    // Set the sending date
    message.setSentDate(new Date());
    // Set the message body
    message.setText("Test message body OK");
    // Send an email
    javaMailSender.send(message);
}
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The test result is sent successfully

4.2 Sending An Email With Picture Resources

@GetMapping("/sendMailWithImg")
@apioperation (value = "produces/produces ",notes =" produces/application/json")
public void sendMailWithImg(a) throws MessagingException {
    // Create a complex message
    MimeMessage mimeMessage = javaMailSender.createMimeMessage();
    MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);
    // Set the email subject
    helper.setSubject("This is a test email with pictures.");
    // Set the sender of the message
    helper.setFrom("[email protected]");
    // Set the mail recipient
    helper.setTo("1******[email protected]");
    // Set the email cc
    helper.setCc("6666***[email protected]");
    // Set up a private cc
    helper.setBcc("l*****[email protected]");
    // Set the sending date
    helper.setSentDate(new Date());
    // Set the message body
    helper.setText("< p > this is a test email with image, this E-mail contains two kinds of images, respectively, the following < / p > < p > the first picture: < / p > < img SRC = 'cid: p01' / > < p > the second image: < / p > < img SRC = 'cid: p02' / >".true);
    helper.addInline("p01".new FileSystemResource(new File("C:\Users\hasee\Desktop\9cae14e699762b40a747d4198.jpg")));
    helper.addInline("p02".new FileSystemResource(new File("C:\Users\hasee\Desktop\ wechat images_202101.jpg")));
    javaMailSender.send(mimeMessage);
}
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The test result is sent successfully