使用SpringBoot发送邮件

邮件发送其实是一个非常常见的需求，用户注册，找回密码等地方，都会用到，Spring Boot 中对于邮件发送，提供了相关的自动化配置类，使得邮件发送变得非常容易。

1、前置工作

目前国内大部分的邮件服务商都不允许直接使用用户名/密码的方式来在代码中发送邮件，都是要先申请授权码，这里以 QQ 邮箱为例，向大家演示授权码的申请流程：

首先我们需要先登录 QQ 邮箱网页版，点击上方的设置按钮：然后点击账户选项卡：在账户选项卡中找到开启POP3/SMTP选项，如下：

点击开启，开启相关功能，开启过程需要手机号码验证，按照步骤操作即可，不赘述。开启成功之后，即可获取一个授权码，将该号码保存好，一会使用。

2、引入依赖、配置邮箱基本信息

<!--集成发送邮件的功能-->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-mail</artifactId>
</dependency>

然后在yml配置文件中进行配置

spring:mail:host: smtp.qq.com # 设置邮箱主机port: 587 # SMTP 服务器的端口username: yyds@qq.com # 设置用户名password:  yyds # 设置密码，该处的密码是QQ邮箱开启SMTP的授权码而非QQ密码mail:from: ${spring.mail.username}to: yyds@163.com

做完这些之后，Spring Boot 就会自动帮我们配置好邮件发送类，相关的配置在

org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration 类中，部分源码如下：

@Configuration
@ConditionalOnClass({ MimeMessage.class, MimeType.class, MailSender.class })
@ConditionalOnMissingBean(MailSender.class)
@Conditional(MailSenderCondition.class)
@EnableConfigurationProperties(MailProperties.class)
@Import({ MailSenderJndiConfiguration.class, MailSenderPropertiesConfiguration.class })
public class MailSenderAutoConfiguration {}

可以看到，导入了另外一个配置 MailSenderPropertiesConfiguration 类，这个类中，提供了邮件发送相关的工具类，源码如下：

@Configuration
@ConditionalOnProperty(prefix = "spring.mail", name = "host")
class MailSenderPropertiesConfiguration {private final MailProperties properties;MailSenderPropertiesConfiguration(MailProperties properties) {this.properties = properties;}@Bean@ConditionalOnMissingBeanpublic JavaMailSenderImpl mailSender() {JavaMailSenderImpl sender = new JavaMailSenderImpl();applyProperties(sender);return sender;}
}

可以看到，这里创建了一个 JavaMailSenderImpl 的实例， JavaMailSenderImpl 是 JavaMailSender 的一个实现，我们将使用 JavaMailSenderImpl 来完成邮件的发送工作。

3、Service层代码

自定义的MailProperties配置类，用于解析mail开头的配置属性

package com.yyds.domain;import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;@Data
@Component
@ConfigurationProperties(prefix = "mail")
public class MailProperties {private String from;private String to;}

service层

package com.yyds.service;import freemarker.template.TemplateException;import javax.mail.MessagingException;
import java.io.IOException;
import java.util.Map;public interface MailService {void sendSimpleMail(String subject, String text) ;void sendHtmlMail(String subject, String text, Map<String, String> attachmentMap) throws MessagingException;void sendTemplateMail(String subject, Map<String, Object> params) throws MessagingException, IOException, TemplateException;
}

package com.yyds.service.impl;import com.yyds.domain.MailProperties;
import com.yyds.service.MailService;
import freemarker.cache.ClassTemplateLoader;
import freemarker.cache.TemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
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 org.springframework.ui.freemarker.FreeMarkerTemplateUtils;
import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer;import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.File;
import java.io.IOException;
import java.util.Map;@Service
public class MailServiceImpl implements MailService {@Autowiredprivate JavaMailSender javaMailSender;@Autowiredprivate MailProperties myMailProperties;/*** 发送简单文本邮件*/@Overridepublic void sendSimpleMail(String subject, String text) {SimpleMailMessage mailMessage = new SimpleMailMessage();mailMessage.setFrom(myMailProperties.getFrom());mailMessage.setTo(myMailProperties.getTo());mailMessage.setSubject(subject);mailMessage.setText(text);javaMailSender.send(mailMessage);}/*** 发送带有链接和附件的复杂邮件*/@Overridepublic void sendHtmlMail(String subject, String text, Map<String, String> attachmentMap) throws MessagingException {MimeMessage mimeMessage = javaMailSender.createMimeMessage();//是否发送的邮件是富文本（附件，图片，html等）MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage, true);messageHelper.setFrom(myMailProperties.getFrom());messageHelper.setTo(myMailProperties.getTo());messageHelper.setSubject(subject);messageHelper.setText(text, true);//重点，默认为false，显示原始html代码，无效果if(attachmentMap != null){attachmentMap.entrySet().stream().forEach(entrySet -> {try {File file = new File(entrySet.getValue());if(file.exists()){messageHelper.addAttachment(entrySet.getKey(), new FileSystemResource(file));}} catch (MessagingException e) {e.printStackTrace();}});}javaMailSender.send(mimeMessage);}/*** 发送模版邮件*/@Overridepublic void sendTemplateMail(String subject, Map<String, Object> params) throws MessagingException, IOException, TemplateException {MimeMessage mimeMessage = javaMailSender.createMimeMessage();MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);helper.setFrom(myMailProperties.getFrom());helper.setTo(myMailProperties.getTo());freemarker.template.Configuration configuration = new freemarker.template.Configuration(freemarker.template.Configuration.VERSION_2_3_19);TemplateLoader templateLoader = new ClassTemplateLoader(this.getClass(), "/templates/");configuration.setTemplateLoader(templateLoader);Template template = configuration.getTemplate("mail.ftl");String html = FreeMarkerTemplateUtils.processTemplateIntoString(template, params);helper.setSubject(subject);helper.setText(html, true);//重点，默认为false，显示原始html代码，无效果javaMailSender.send(mimeMessage);}
}

4、发送邮件

4.1 测试发送简单文本邮件

@SpringBootTest(classes = BootStartApplication.class)
public class MimeMailTest {@Autowiredprivate MailService mailService;@Testpublic void sendMail() {mailService.sendSimpleMail("测试Springboot发送邮件", "发送邮件...");}
}

4.2 测试发送带有链接和附件的复杂邮件

package com.yyds;import com.yyds.service.MailService;
import freemarker.template.TemplateException;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import javax.mail.MessagingException;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;@SpringBootTest(classes = BootStartApplication.class)
public class MimeMailTest {@Autowiredprivate MailService mailService;@Testpublic void testMail() throws MessagingException {Map<String, String> attachmentMap = new HashMap<>();attachmentMap.put("附件", "D:\\D_ENL_MRO数据统计.xlsx");mailService.sendHtmlMail("测试Springboot发送带附件的邮件2", "欢迎进入<a href=\"http://www.baidu.com\">百度首页</a>", attachmentMap);}}

4.3 测试发送发送模版邮件

首先需要引入 Freemarker 依赖：

		<!--整合freemarker--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-freemarker</artifactId></dependency>

然后在 resources/templates 目录下创建一个 mail.ftl 作为邮件发送模板：

<html><body><h3>你好， <span style="color: red;">${username}</span>, 这是一封模板邮件!</h3></body>
</html>

package com.yyds;import com.yyds.service.MailService;
import freemarker.template.TemplateException;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import javax.mail.MessagingException;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;@SpringBootTest(classes = BootStartApplication.class)
public class MimeMailTest {@Autowiredprivate MailService mailService;@Testpublic void testFreemarkerMail() throws MessagingException, IOException, TemplateException {Map<String, Object> params = new HashMap<>();params.put("username", "Tom");mailService.sendTemplateMail("测试Springboot发送模版邮件", params);}}