1、新建项目sc-mail,对应的pom.xml文件如下
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>spring-cloud</groupId>
    <artifactId>sc-mail</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>sc-mail</name>
    <url>http://maven.apache.org</url>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
    </parent>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Finchley.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-mail</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>2、新建配置文件application.yml
spring:
    application:
        name: sc-mail
    mail:
        host: smtp.qq.com #邮箱服务器地址
        port: 465
        username: 515768476@qq.com #用户名
        password: vfcqhwsnnwugbhcx #密码 (改成自己的密码)
        default-encoding: UTF-8
        properties:
            mail:
                smtp:
                    ssl:
                        enable:
                            true3、新建邮件发送服务类
package sc.mail.service.impl;
import java.io.File;
import javax.mail.internet.MimeMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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.stereotype.Service;
import sc.mail.service.MailService;
@Service
public class MailServiceImpl implements MailService {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());
    @Autowired
    private JavaMailSender mailSender;
    /**
     * 文本
     * @param from
     * @param to
     * @param subject
     * @param content
     */
    @Override
    public void sendSimpleMail(String from, String to, String subject, String content) {
        SimpleMailMessage message = new SimpleMailMessage();
        message.setFrom(from);
        message.setTo(to);
        message.setSubject(subject);
        message.setText(content);
        try {
            mailSender.send(message);
            logger.info("simple mail had send。");
        } catch (Exception e) {
            logger.error("send mail error", e);
        }
    }
    /**
     * @param from
     * @param to
     * @param subject
     * @param content
     */
    public void sendTemplateMail(String from, String to, String subject, String content) {
            MimeMessage message = mailSender.createMimeMessage();
            try {
                    //true表示需要创建一个multipart message
                    MimeMessageHelper helper = new MimeMessageHelper(message, true);
                    helper.setFrom(from);
                    helper.setTo(to);
                    helper.setSubject(subject);
                    helper.setText(content, true);
                    mailSender.send(message);
                    logger.info("send template success");
            } catch (Exception e) {
                    logger.error("send template eror", e);
            }
    }
    /**
     * 附件
     * 
     * @param from
     * @param to
     * @param subject
     * @param content
     * @param filePath
     */
    public void sendAttachmentsMail(String from, String to, String subject, String content, String filePath){
            MimeMessage message = mailSender.createMimeMessage();
            try {
                    MimeMessageHelper helper = new MimeMessageHelper(message, true);
                    helper.setFrom(from);
                    helper.setTo(to);
                    helper.setSubject(subject);
                    helper.setText(content, true);
                    FileSystemResource file = new FileSystemResource(new File(filePath));
                    String fileName = filePath.substring(filePath.lastIndexOf(File.separator));
                    helper.addAttachment(fileName, file);
                    mailSender.send(message);
                    logger.info("send mail with attach success。");
            } catch (Exception e) {
                    logger.error("send mail with attach success", e);
            }
    }
    /**
     * 发送内嵌图片
     * 
     * @param from
     * @param to
     * @param subject
     * @param content
     * @param imgPath
     * @param imgId
     */
    public void sendInlineResourceMail(String from, String to, String subject, String content,
            String imgPath, String imgId){
            MimeMessage message = mailSender.createMimeMessage();
            try {
                    MimeMessageHelper helper = new MimeMessageHelper(message, true);
                    helper.setFrom(from);
                    helper.setTo(to);
                    helper.setSubject(subject);
                    helper.setText(content, true);
                    FileSystemResource res = new FileSystemResource(new File(imgPath));
                    helper.addInline(imgId, res);
                    mailSender.send(message);
                    logger.info("send inner resources success。");
            } catch (Exception e) {
                    logger.error("send inner resources fail", e);
            }
    }
}4、新建测试类
package sc.mail;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import sc.mail.service.MailService;
@RunWith(SpringRunner.class)
@SpringBootTest
public class MailSendTest {
    @Autowired
    private MailService mailService;
    @Test
    public void sendSimpleMailTest() {
        mailService.sendSimpleMail("515768476@qq.com", "happy.huangjinjin@163.com", 
                "sendSimpleMailTest", "sendSimpleMailTest from 515768476@qq.com");
    }
    @Test
    public void sendTemplateMailTest() {
        String html = "<html><body>"
                + " <div> "
                + "    sendTemplateMailTest from 515768476@qq.com </br>"
                + "    <b>这是模板邮件</b>"
                + "</div>"
                + "</body></html>";
        mailService.sendTemplateMail("515768476@qq.com", "happy.huangjinjin@163.com", 
                "sendTemplateMailTest", html);
    }
    @Test
    public void sendAttachmentsMailTest() {
        String filePath = "D:\\springcloudws\\sc-mail\\src\\main\\java\\sc\\mail\\service\\impl\\MailServiceImpl.java";
        mailService.sendAttachmentsMail("515768476@qq.com", "happy.huangjinjin@163.com", 
                "sendAttachmentsMailTest", "sendAttachmentsMailTest from 515768476@qq.com", filePath);
    }
    @Test
    public void sendInlineResourceMailTest() {
        String imgId = "img1";
        String content = "<html><body>"
                + "sendInlineResourceMailTest:<img src=\‘cid:" + imgId + "\‘ >"
                        + "</body></html>";
        String imgPath = "D:\\springcloudws\\sc-mail\\src\\main\\resources\\20181015223228.jpg";
        mailService.sendInlineResourceMail("515768476@qq.com", "happy.huangjinjin@163.com", 
                "sendAttachmentsMailTest", content, imgPath, imgId);
    }
}5、运行测试类验证是否发送邮件成功br/>登录happy.huangjinjin@163.com邮箱
简单邮件
模板邮件
附件邮件
内嵌图片邮件
原文:https://blog.51cto.com/13538361/2492011