邮件（一）：Springboot+thymeleaf的发邮件部分

1 邮件配置部分

qq邮箱授权码获取

java 邮件属性配置

（1）写在代码中(任选其一，建议2)

JavaMailSenderImpl javaMailSender = new JavaMailSenderImpl();
javaMailSender.setHost("smtp.qq.com");
javaMailSender.setPort(25);
javaMailSender.setUsername("1464245418@qq.com");
javaMailSender.setPassword("yourAuthorizationCode");
Properties properties = new Properties();
properties.setProperty("mail.host", "smtp.qq.com");
properties.setProperty("mail.transport.protocol", "smtp");
properties.setProperty("mail.smtp.auth", "true");
properties.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
properties.setProperty("mail.smtp.port", "25");
properties.setProperty("mail.smtp.socketFactory.port", "25");

javaMailSender.setJavaMailProperties(properties);

（2）写在.properties文件中

spring.mail.host=smtp.qq.com
spring.mail.port=25
spring.mail.username=1464245418@qq.com
spring.mail.password=yourAuthorizationCode

2 邮件简单发送

主要使用JavaMail包，邮件内容使用thymeleaf

<dependencies>
  <!--SpringBoot 起步依赖-->
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
  </dependency>
  <!--JavaMail-->
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-mail</artifactId>
  </dependency>
  <!--thymeleaf模板-->
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
  </dependency>
</dependencies>

发送邮件

@Resource
private TemplateEngine templateEngine;
@Resource
private JavaMailSenderImpl javaMailSender;

 /**
   * @description 仅发送简单邮件.
   * @author liuhongchen
 */  
public void sendSimpleMail() {
  // 创建MIMEMessage对象
  MimeMessage message = javaMailSender.createMimeMessage();
  try {
      //true表示需要创建一个multipart message
      MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
      String nick;
      try {
        nick = MimeUtility.encodeText("测试邮件");
      } catch (UnsupportedEncodingException e) {
        MailService.log.error("邮件nickName有问题：" + e.getMessage());
        throw new ServiceException(MessageCode.SYSTEM_ERROR);
      }

      // 邮件发送信息(from,to,cc)
      helper.setFrom(new InternetAddress(nick + "<1464245418@qq.com>"));
      helper.setTo(new String[]{"1464245418@qq.com"});
      helper.setCc(new String[]{"1464245418@qq.com"});
      helper.setSubject("这是邮件的主题");

      // 注入邮件内容模板
      helper.setText("<h1>This is actual message</h1>", "text/html", true);

      try {
        javaMailSender.setPassword("记得填密码");
        javaMailSender.setUsername("1464245418@qq.com");
        javaMailSender.send(message);
        MailService.log.info("html邮件发送成功");
      } catch (Exception e) {
        MailService.log.error("邮件发送有问题：" + e.getMessage());
      }

    } catch (Exception e) {
      MailService.log.error("发送html邮件时发生异常！", e);
    }
}

3 邮件带附件、内嵌图片(使用thymeleaf)

发送邮件代码

/**
  * 发送带附件和内嵌图片的邮件.
  * 
  * @param templateName   thymeleaf模板名
  * @param mailAccount    邮箱账号密码
  * @param contextVars    邮件内容变量
  * @param inlineImgMap   内嵌图片Map
  * @param attachmentList 附件List
  * @return void
  * @author liuhongchen
  * @date 2020/8/21 10:36 上午
  */
@Async
public void sendSimpleMail(String templateName, Map<String, Object> contextVars,
    Map<String, String> inlineImgMap, Map<String, DataSource> attachmentList) {
  // 解决：放置附件名过长被截断，从而产生乱码问题
  System.getProperties().setProperty("mail.mime.splitlongparameters", "false");

  MimeMessage message = javaMailSender.createMimeMessage();

  try {
    //true表示需要创建一个multipart message
    MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
    String nick;
    try {
      nick = MimeUtility.encodeText("烛龙监控平台");
    } catch (UnsupportedEncodingException e) {
      MailService.log.error("邮件nickName有问题：" + e.getMessage());
      throw new ServiceException(MessageCode.SYSTEM_ERROR);
    }

    // 邮件发送信息(from,to,cc)
    helper.setFrom(new InternetAddress(nick + "<1464245418@qq.com>"));
    helper.setTo(new String[]{"1464245418@qq.com"});
    helper.setCc(new String[]{"1464245418@qq.com"});
    helper.setSubject("这是邮件的主题");

    // 注入邮件模板（注入变量和邮件模板内容）
    Context context = new Context();
    context.setVariables(contextVars);
    String emailContext = templateEngine.process(templateName, context);
    helper.setText(emailContext, true);

    // 附件
    if (attachmentList != null) {
      for (Entry<String, DataSource> fileEntry : attachmentList.entrySet()) {
        helper.addAttachment(fileEntry.getKey(), fileEntry.getValue());
      }
    }
    // 插入内嵌资源
    if (inlineImgMap != null) {
      for (Entry<String, String> imgEntry : inlineImgMap.entrySet()) {
        helper.addInline(imgEntry.getKey(), new File(imgEntry.getValue()));
      }
    }

    try {
      javaMailSender.setPassword("记得填密码");
      javaMailSender.setUsername("1464245418@qq.com");
      javaMailSender.send(message);
      MailService.log.info("html邮件发送成功");
    } catch (Exception e) {
      MailService.log.error("邮件发送有问题：" + e.getMessage());
    }

  } catch (Exception e) {
    MailService.log.error("发送html邮件时发生异常！", e);
  }
}

thymeleaf模板

<!DOCTYPE html>
<html lang="zh-Hans" xmlns:th="http://www.thymeleaf.org" xmlns="http://www.w3.org/1999/html">
<head>
<meta charset="UTF-8"/>
</head>
<body>
    <table th:if="${sendType eq 'preview'}">
          <tr>
            <td align="center"><img th:src="${previewAndroidTimeTop}" width="900"  /></td>
          </tr>
          <tr >
            <td align="center"><img th:src="${previewIosTimeTop}" width="900"  /></td>
          </tr>
        </table>
</body>
</html>

其中的变量sendType在contextVar中设置

Map<String, Object> contextVars = new HashMap<>(16);
contextVars.put("sendType", "preview");

图片可以直接放置图片链接，但是会出现一个问题，邮件会出于保护隐私不显示图片，此时需要手动点击”下载图片“，才会显示。
使用cid的好处就是可以避免这一操作，但需要使用图片的绝对位置，后续需要删除该图片

Map<String, String> inlineImgMap = new HashMap<>(16);
inlineImgMap.put("androidTimeTop", "/Users/liuhongchen/code/androidTimeTop.png"));
inlineImgMap.put("iosTimeTop", "/Users/liuhongchen/code/iosTimeTop.png"));