SpringBoot 整合Mail邮件

1. 邮件与协议

　　A. smtp(简单邮件传输协议)：smtp是Simple Mail Transfer Protocol缩写，它是一组用于从源地址到目的地址传输邮件的规范，通过它来控制邮件的中转方式，smtp认证要求必须提供账号和密码才能登陆服务器，其目的是避免用户受到垃圾邮件的干扰；

　　B. pop3(邮局协议)：pop3是Post Office Protocol 3缩写，支持客户端远程管理服务器端的邮件；

　　C. smtp服务器地址：网易163/QQ/126/sina/aliyun邮箱 ——> smtp.163.com/smtp.qq.com/ smtp.126.com/smtp.sina.com/ smtp.aliyun.com；

　　D. 邮件分简单邮件和复杂邮件，复杂邮件有html格式邮件、带附件格式邮件、带静态资源邮件、基于Freemarker模板的邮件；

2. pom.xml Maven依赖

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

3. 邮箱信息配置

　　A. application.properties文件配置

　　B. 前端传输参数动态配置

　　注意：若使用配置文件设置邮箱信息，可使用JavaMailSender接口发送邮件；若动态配置邮箱信息，需使用JavaMailSenderImpl实现类发送邮件；它们是Java后端发送邮件和集成邮件服务的主流工具。

4. 发送邮件

　　A. 发送简单邮件

package com.ruhuanxingyun.dcy.service.manage.service;

import com.ruhuanxingyun.dcy.service.manage.model.dto.MailDTO;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.mail.MailProperties;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.stereotype.Service;

/**
 * @description: 邮件 服务层
 * @author: ruphie
 * @date: Create in 2021/4/17 11:00
 * @company: ruhuanxingyun
 */
@Slf4j
@Service
public class MailService {

    @Autowired
    private MailProperties mailProperties;

    @Autowired
    private JavaMailSender javaMailSender;

    /**
     * 发送简单邮件
     * @param mailDTO 邮件信息
     */
    public void sendSimpleMail(MailDTO mailDTO) {
        SimpleMailMessage simpleMailMessage = new SimpleMailMessage();
        // 邮件发送人
        simpleMailMessage.setFrom(mailProperties.getUsername());
        // 邮件收件人
        simpleMailMessage.setTo(mailDTO.getMailRecipient());
        //邮件主题
        simpleMailMessage.setSubject(mailDTO.getSubject());
        //邮件内容
        simpleMailMessage.setText(mailDTO.getContent());

        // 发送邮件
        javaMailSender.send(simpleMailMessage);
    }

}

　　B. 发送HTML邮件　　

package com.ruhuanxingyun.service.system.impl;

import com.ruhuanxingyun.entity.system.Mail;
import com.ruhuanxingyun.service.system.IMailService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.javamail.JavaMailSenderImpl;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Service;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.util.Properties;

/**
 * @description: 邮件工具接口实现层
 * @author: ruphie
 * @date: Create in 2020/1/4 16:58
 * @company: ruhuanxingyun
 */
@Service
public class MailServiceImpl implements IMailService {

    @Autowired
    private JavaMailSenderImpl javaMailSender;

    @Override
    public void sendHtmlMail(Mail mail){
        javaMailSender.setDefaultEncoding("UTF-8");
        javaMailSender.setHost(mail.getMailHost());
　　　　　javaMailSender.setPort(mail.getMailPort());
        // 是否SSL加密连接
        if (mail.getOnSsl() == 2) {
            Properties properties = new Properties();
            properties.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
            javaMailSender.setJavaMailProperties(properties);
        }
        // 需要验证邮箱用户名和密码
        if (mail.getOnAuth() == 2) {
            javaMailSender.setUsername(mail.getUsername());
            javaMailSender.setPassword(mail.getPassword());
        }

        MimeMessage mimeMessage = javaMailSender.createMimeMessage();
        try {
            MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage, true);
            messageHelper.setFrom(mail.getMailSender());
            messageHelper.setTo(mail.getMailRecipient());
            messageHelper.setSubject(mail.getSubject());
            messageHelper.setText(mail.getContent(), true);

            javaMailSender.send(mimeMessage);
        } catch (MessagingException e) {
            e.printStackTrace();

            throw new RuntimeException("发送测试邮件失败");
        }
    }

}