SpringBoot整合邮件服务

发送邮件应该是网站的必备功能之一，什么注册验证，忘记密码或者是给用户发送营销信息。最早期的时候我们会

使用 JavaMail 相关 api 来写发送邮件的相关代码，后来 Spring 推出了 JavaMailSender 更加简化了邮件发送的过

程，在之后 Spring Boot 对此进行了封装就有了现在的 spring-boot-starter-mail ,本章文章的介绍主要来自

于此包。

1、简单使用

1.1 pom依赖

pom 包里面添加 spring-boot-starter-mail 包引用

<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.0.RELEASE</version>
        <relativePath/>
    </parent>

    <groupId>com.example</groupId>
    <artifactId>spring-boot-mail</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-mail</name>
    <description>spring-boot-mail</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

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

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>RELEASE</version>
        </dependency>

        <dependency>
            <groupId>com.sun.mail</groupId>
            <artifactId>javax.mail</artifactId>
            <version>RELEASE</version>
        </dependency>

        <!-- 模板引擎 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

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

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

1.2 在 application.properties 中添加邮箱配置

spring.application.name=spirng-boot-mail
# 邮箱服务器地址
spring.mail.host=smtp.163.com
# 用户名
spring.mail.username=15110820283@163.com
# 密码
spring.mail.password=EVNCPVURUPIFNAXG
spring.mail.default-encoding=UTF-8
# 谁来发送邮件
mail.fromMail.addr=15110820283@163.com

1.3 编写 mailService

package com.example.service;

public interface MailService {

    void sendSimpleMail(String to, String subject, String content);

    void sendHtmlMail(String to, String subject, String content);

    void sendAttachmentsMail(String to, String subject, String content, String filePath);

    void sendInlineResourceMail(String to, String subject, String content, String rscPath, String rscId);

}

package com.example.service.impl;

import com.example.service.MailService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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.Component;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.File;

@Component
public class MailServiceImpl implements MailService {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    private JavaMailSender mailSender;

    @Value("${mail.fromMail.addr}")
    private String from;

    /**
     * 发送文本邮件
     *
     * @param to
     * @param subject
     * @param content
     */
    @Override
    public void sendSimpleMail(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("简单邮件已经发送。");
        } catch (Exception e) {
            logger.error("发送简单邮件时发生异常！", e);
        }
    }

    /**
     * 发送html邮件
     *
     * @param to
     * @param subject
     * @param content
     */
    @Override
    public void sendHtmlMail(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("html邮件发送成功");
        } catch (MessagingException e) {
            logger.error("发送html邮件时发生异常！", e);
        }
    }

    /**
     * 发送带附件的邮件
     *
     * @param to
     * @param subject
     * @param content
     * @param filePath
     */
    @Override
    public void sendAttachmentsMail(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);
            //helper.addAttachment("test"+fileName, file);

            mailSender.send(message);
            logger.info("带附件的邮件已经发送。");
        } catch (MessagingException e) {
            logger.error("发送带附件的邮件时发生异常！", e);
        }
    }


    /**
     * 发送正文中有静态资源（图片）的邮件
     *
     * @param to
     * @param subject
     * @param content
     * @param rscPath
     * @param rscId
     */
    @Override
    public void sendInlineResourceMail(String to, String subject, String content, String rscPath, String rscId) {
        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(rscPath));
            helper.addInline(rscId, res);
            mailSender.send(message);
            logger.info("嵌入静态资源的邮件已经发送。");
        } catch (MessagingException e) {
            logger.error("发送嵌入静态资源的邮件时发生异常！", e);
        }
    }
}

1.4 启动类

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {

        SpringApplication.run(Application.class, args);
    }

}

1.5 编写test类进行测试

package com.example.service;

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 org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.Context;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MailServiceTest {

    @Autowired
    private MailService mailService;

    @Autowired
    private TemplateEngine templateEngine;

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容文本内容
    @Test
    public void testSimpleMail() throws Exception {
        mailService.sendSimpleMail("2420309401@qq.com","test simple mail"," hello this is simple mail");
    }

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为html格式的内容
    @Test
    public void testHtmlMail() throws Exception {
        String content="<html>\n" +
                "<body>\n" +
                "    <h3>hello world ! 这是一封html邮件!</h3>\n" +
                "</body>\n" +
                "</html>";
        mailService.sendHtmlMail("2420309401@qq.com","test simple mail",content);
    }

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为文本内容,带附件
    @Test
    public void sendAttachmentsMail() {
        String filePath="C:\\Users\\Administrator\\Pictures\\Camera Roll\\img19.jpg";
        mailService.sendAttachmentsMail("2420309401@qq.com", "主题：带附件的邮件", "有附件，请查收！", filePath);
    }

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为文本内容,发送正文中有静态资源（图片）的邮件
    @Test
    public void sendInlineResourceMail() {
        String rscId = "neo006";
        String content="<html><body>这是有图片的邮件：<img src=\'cid:" + rscId + "\' ></body></html>";
        String imgPath = "C:\\Users\\Administrator\\Pictures\\Camera Roll\\img19.jpg";
        mailService.sendInlineResourceMail("2420309401@qq.com", "主题：这是有图片的邮件", content, imgPath, rscId);
    }

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为模板邮件
    @Test
    public void sendTemplateMail() {
        //创建邮件正文
        Context context = new Context();
        context.setVariable("id", "006");
        String emailContent = templateEngine.process("emailTemplate", context);
        mailService.sendHtmlMail("2420309401@qq.com","主题：这是模板邮件",emailContent);
    }
}

1.5.1 发送普通文本

package com.example.service;

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 org.thymeleaf.TemplateEngine;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MailServiceTest {

    @Autowired
    private MailService mailService;

    @Autowired
    private TemplateEngine templateEngine;

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容文本内容
    @Test
    public void testSimpleMail() throws Exception {
        mailService.sendSimpleMail("2420309401@qq.com", "test simple mail", " hello this is simple mail");
    }
}

但是在正常使用的过程中，我们通常在邮件中加入图片或者附件来丰富邮件的内容，下面讲介绍如何使用 Spring

Boot 来发送丰富的邮件。

1.5.2 发送 html 格式邮件

package com.example.service;

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 org.thymeleaf.TemplateEngine;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MailServiceTest {

    @Autowired
    private MailService mailService;

    @Autowired
    private TemplateEngine templateEngine;

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为html格式的内容
    @Test
    public void testHtmlMail() throws Exception {
        String content = "<html>\n" +
                "<body>\n" +
                "    <h3>hello world ! 这是一封html邮件!</h3>\n" +
                "</body>\n" +
                "</html>";
        mailService.sendHtmlMail("2420309401@qq.com", "test simple mail", content);
    }
    
}

1.5.3 发送带附件的邮件

package com.example.service;

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 org.thymeleaf.TemplateEngine;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MailServiceTest {

    @Autowired
    private MailService mailService;

    @Autowired
    private TemplateEngine templateEngine;

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为文本内容,带附件
    @Test
    public void sendAttachmentsMail() {
        String filePath = "C:\\Users\\Administrator\\Pictures\\Camera Roll\\img19.jpg";
        mailService.sendAttachmentsMail("2420309401@qq.com", "主题：带附件的邮件", "有附件，请查收！", filePath);
    }
    
}

添加多个附件可以使用多条 helper.addAttachment(fileName, file)

1.5.4 发送带静态资源的邮件

邮件中的静态资源一般就是指图片。

package com.example.service;

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 org.thymeleaf.TemplateEngine;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MailServiceTest {

    @Autowired
    private MailService mailService;

    @Autowired
    private TemplateEngine templateEngine;

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为文本内容,发送正文中有静态资源（图片）的邮件
    @Test
    public void sendInlineResourceMail() {
        String rscId = "neo006";
        String content = "<html><body>这是有图片的邮件：<img src=\'cid:" + rscId + "\' ></body></html>";
        String imgPath = "C:\\Users\\Administrator\\Pictures\\Camera Roll\\img19.jpg";
        mailService.sendInlineResourceMail("2420309401@qq.com", "主题：这是有图片的邮件", content, imgPath, rscId);
    }
    
}

添加多个图片可以使用多条 <img src='cid:" + rscId + "' > 和 helper.addInline(rscId, res) 来实现

2、按照模板发送

邮件模板emailTemplate.html

<!DOCTYPE html>
<html lang="zh" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8"/>
        <title>Title</title>
    </head>
    <body>
        您好,这是验证邮件,请点击下面的链接完成验证,<br/>
        <a href="#" th:href="@{ http://www.ityouknow.com/neo/{id}(id=${id}) }">激活账号</a>
    </body>
</html>

package com.example.service;

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 org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.Context;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MailServiceTest {

    @Autowired
    private MailService mailService;

    @Autowired
    private TemplateEngine templateEngine;

    // 邮件发送到2420309401@qq.com,邮件标题test simple mail,内容为模板邮件
    @Test
    public void sendTemplateMail() {
        //创建邮件正文
        Context context = new Context();
        context.setVariable("id", "006");
        String emailContent = templateEngine.process("emailTemplate", context);
        mailService.sendHtmlMail("2420309401@qq.com", "主题：这是模板邮件", emailContent);
    }
}

到此所有的邮件发送服务已经完成了。

3、邮件系统

上面发送邮件的基础服务就这些了，但是如果我们要做成一个邮件系统的话还需要考虑以下几个问题：

3.1 邮件模板

我们会经常收到这样的邮件：

尊敬的neo用户：
	恭喜您注册成为xxx网的用户,，同时感谢您对xxx的关注与支持并欢迎您使用xx的产品与服务。

其中只有 neo 这个用户名在变化，其它邮件内容均不变，如果每次发送邮件都需要手动拼接的话会不够优雅，并

且每次模板的修改都需要改动代码的话也很不方便，因此对于这类邮件需求，都建议做成邮件模板来处理。模板的

本质很简单，就是在模板中替换变化的参数，转换为 html 字符串即可，这里以thymeleaf为例来演示。

1、pom 中导入 thymeleaf 的包

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

2、在resorces/templates下创建emailTemplate.html

<!DOCTYPE html>
<html lang="zh" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8"/>
        <title>Title</title>
    </head>
    <body>
        您好,这是验证邮件,请点击下面的链接完成验证,<br/>
        <a href="#" th:href="@{ http://www.ityouknow.com/neo/{id}(id=${id}) }">激活账号</a>
    </body>
</html>

3、解析模板并发送

@Test
public void sendTemplateMail() {
    //创建邮件正文
    Context context = new Context();
    context.setVariable("id", "006");
    String emailContent = templateEngine.process("emailTemplate", context);
    mailService.sendHtmlMail("2420309401@qq.com", "主题：这是模板邮件", emailContent);
}

3.2 发送失败

因为各种原因，总会有邮件发送失败的情况，比如：邮件发送过于频繁、网络异常等。在出现这种情况的时候，我

们一般会考虑重新重试发送邮件，会分为以下几个步骤来实现：

• 1、接收到发送邮件请求，首先记录请求并且入库。

• 2、调用邮件发送接口发送邮件，并且将发送结果记录入库。

• 3、启动定时系统扫描时间段内，未发送成功并且重试次数小于3次的邮件，进行再次发送

3.3 异步发送

很多时候邮件发送并不是我们主业务必须关注的结果，比如通知类、提醒类的业务可以允许延时或者失败。这个时

候可以采用异步的方式来发送邮件，加快主交易执行速度，在实际项目中可以采用MQ发送邮件相关参数，监听到

消息队列之后启动发送邮件。