1、环境约束

• win10 64位操作系统
• idea2018.1.5
• maven-3.0.5
• jdk-8u162-windows-x64

2、前提约束

• 完成springboot创建web项目 https://www.jianshu.com/p/de979f53ad80
  注意，作者使用的springboot版本是2.1.8.RELEASE

3、操作步骤

• 配置application.properties

#邮箱服务器地址，163：smtp.163.com；126：smtp.126.com ；qq：smtp.qq.com 
spring.mail.host=smtp.163.com
#用户名
spring.mail.username=langli2049@163.com
#开启POP3之后设置的客户端授权码，注意这不是密码，是在登录邮箱管理界面之后获取的授权码
spring.mail.password=IOINRNXXXXXCYDGQ
spring.mail.default-encoding=UTF-8

• 在pom.xml中加入依赖：

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

• 在主启动类统计目录下创建MailService.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
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.stereotype.Service;

import javax.mail.internet.MimeMessage;
import java.io.File;
import java.util.Map;

@Service
public class MailService {
    @Autowired
    private JavaMailSender mailSender;

    @Value("${spring.mail.username}")
    private String sender;

    /**
     * 发送普通邮件
     */
    public void sendSimpleMailMessge(String to, String subject, String content) throws Exception {
        SimpleMailMessage message = new SimpleMailMessage();
        message.setFrom(sender);
        message.setTo(to);
        message.setSubject(subject);
        message.setText(content);
        mailSender.send(message);
    }

    /**
     * 发送 HTML 邮件
     */
    public void sendMimeMessge(String to, String subject, String content) throws Exception {
        MimeMessage message = mailSender.createMimeMessage();
        //true表示需要创建一个multipart message
        MimeMessageHelper helper = new MimeMessageHelper(message, true);
        helper.setFrom(sender);
        helper.setTo(to);
        helper.setSubject(subject);
        helper.setText(content, true);
        mailSender.send(message);
    }

    /**
     * 发送带附件的邮件
     */
    public void sendMimeMessge(String to, String subject, String content, String filePath) throws Exception {
        MimeMessage message = mailSender.createMimeMessage();
        //true表示需要创建一个multipart message
        MimeMessageHelper helper = new MimeMessageHelper(message, true);
        helper.setFrom(sender);
        helper.setTo(to);
        helper.setSubject(subject);
        helper.setText(content, true);

        FileSystemResource file = new FileSystemResource(new File(filePath));
        String fileName = file.getFilename();
        helper.addAttachment(fileName, file);

        mailSender.send(message);
    }

    /**
     * 发送带多个静态文件的邮件
     */
    public void sendMimeMessge(String to, String subject, String content, Map<String, String> rscIdMap) throws Exception {
        MimeMessage message = mailSender.createMimeMessage();
        //true表示需要创建一个multipart message
        MimeMessageHelper helper = new MimeMessageHelper(message, true);
        helper.setFrom(sender);
        helper.setTo(to);
        helper.setSubject(subject);
        helper.setText(content, true);

        for (Map.Entry<String, String> entry : rscIdMap.entrySet()) {
            FileSystemResource file = new FileSystemResource(new File(entry.getValue()));
            helper.addInline(entry.getKey(), file);
        }
        mailSender.send(message);
    }
}

• 在主启动类同级目录下创建MailController.java

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
public class MailController {

    @Resource
    MailService mailService;

    @GetMapping("/sendemail")
    public String send1() throws Exception {
        mailService.sendSimpleMailMessge("langli2049@163.com", "hello", "ceshi");
        return "ok";
    }

    @GetMapping("/sendhtmlemail")
    public String send2() throws Exception {
        mailService.sendMimeMessge("langli2049@163.com", "hello", "<html><h1>1234</h1></html>");
        return "ok";
    }

    @GetMapping("/sendhfilemail")
    public String send3() throws Exception {
        mailService.sendMimeMessge("langli2049@163.com", "hello", "<html><h1>1234</h1></html>", "D:\\logback.log");
        return "ok";
    }
}

• 启动，测试
  （1）访问 http://localhost:8080/sendhfilemail，发送带附件的邮件到langli2049@163.com
  （2）访问 http://localhost:8080/sendhtmlemail，发送html静态页面邮件到langli2049@163.com
  （3）访问 http://localhost:8080/sendemail，发送普通邮件到langli2049@163.com