1、登录邮箱

2、点击“设置”，进入“账户”

3、获取授权码

4、后端代码

maven依赖：

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-mail</artifactId>
        </dependency>

bootstrap.yml：

spring:
	mail:
    		host: smtp.qq.com
    		port: 587
    		username: 1050100468@qq.com
    		password: ************

注：password 为上面获取的授权码！！！?

MailService.java：

package application.service;

import lombok.RequiredArgsConstructor;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Service;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.nio.charset.StandardCharsets;

/**
 * @author: wtl
 * @License: (C) Copyright 2021, wtl Corporation Limited.
 * @Contact: 1050100468@qq.com
 * @Date: 2021/10/29 9:35 上午
 * @Version: 1.0
 * @Description:
 */
@Service
@RequiredArgsConstructor
public class MailService {

    private final JavaMailSender mailSender;

    public void sendMail(String subject,String from,String to) throws Exception{
        String contentPage = "/Users/tlzs/Desktop/working/IdeaProjects/SpringBoot/src/main/resources/static/htmls/index.html";
        BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(contentPage));
        int length = -1;
        byte [] buffer = new byte[10240];
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        while ((length = bufferedInputStream.read(buffer))!= -1){
            byteArrayOutputStream.write(buffer,0,length);
        }

        bufferedInputStream.close();

        String emailContent = new String(byteArrayOutputStream.toByteArray(), StandardCharsets.UTF_8);

        MimeMessage message = mailSender.createMimeMessage();
        MimeMessageHelper mimeMessageHelper = null;
        try {
            mimeMessageHelper = new MimeMessageHelper(message, true);
            //设置发送来源账号
            mimeMessageHelper.setFrom(from);
            // 发往目的的账号
            mimeMessageHelper.setTo(to);
            //设置抄送人员账号
            mimeMessageHelper.setCc(new String[]{"123@qq.com","456@qq.com"});
            // 设置主题
            mimeMessageHelper.setSubject(subject);
            mimeMessageHelper.setText(emailContent, true);
        } catch (MessagingException e) {
            e.printStackTrace();
        }

        mailSender.send(message);
    }
}

注意：邮箱是支持html代码和html代码时段的。

index.html：

<h1>Hello,world!!!</h1>
<a href="https://www.baidu.com" style="color: blue;">我的百度</a>

或者：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>index页面</title>
</head>
<body>
<h1>Hello,world!!!</h1>
<a href="https://www.baidu.com" style="color: blue;">我的百度</a>
</body>
</html>

?如果以工具类的方式来进行初始化，会出现编码问题：

package cn.com.yusys.aiops.alarm.util;

import cn.com.yusys.aiops.alarm.notify.AlarmNotifyReceiver;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSenderImpl;
import org.springframework.mail.javamail.MimeMessageHelper;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;


public class MailUtil {
    private static final Logger logger = LoggerFactory.getLogger(MailUtil.class);
    private static final JavaMailSenderImpl javaMailSender;

    static {
        javaMailSender = new JavaMailSenderImpl();
        javaMailSender.setProtocol("smtp");
        javaMailSender.setHost("mail.yusys.com.cn");
        javaMailSender.setPort(25);
        javaMailSender.setUsername("yucc-aiops-admin@yusys.com.cn");
        javaMailSender.setPassword("Aiops123");
    }

    public static boolean mailSender(String sendTo,String subject,String msg) throws Exception {
        try {
            javaMailSender.setDefaultEncoding("utf-8");
            // 创一个邮件对象
            MimeMessage message = javaMailSender.createMimeMessage();
            MimeMessageHelper mimeMessageHelper = null;
            try {
                mimeMessageHelper = new MimeMessageHelper(message, true);
                mimeMessageHelper.setFrom("yucc-aiops-admin@yusys.com.cn");
                mimeMessageHelper.setTo(sendTo);
//                mimeMessageHelper.setCc(new String[]{"123@qq.com","456@qq.com"});
                //邮件主题.
                mimeMessageHelper.setSubject(subject);
                mimeMessageHelper.setText(msg, true);
            } catch (MessagingException e) {
                e.printStackTrace();
            }

            javaMailSender.send(message);//发送邮件
            return true;
        }catch (Exception e){
            e.printStackTrace();
            return false;
        }
    }


    public static void main(String[] args) throws Exception {
        mailSender("yucc-aiops-admin@yusys.com.cn","中文测试","<!DOCTYPE html>\n" +
                "<html lang=\"zh\">\n" +
                "<head>\n" +
                "    <meta charset=\"UTF-8\">\n" +
                "    <title>告警内容</title>\n" +
                "</head>\n" +
                "<body>\n" +
                "<p>你好</p>" +
                "</body>\n" +
                "</html>");
    }
}

解决办法为：

javaMailSender.setDefaultEncoding("utf-8");
// 创一个邮件对象
MimeMessage message = javaMailSender.createMimeMessage();

在 javaMailSender.createMimeMessage();之前设置编码格式。