[Java] JavaMail 发送带图片的 html 格式的邮件

JavaMail 发送的邮件正文和附件是相互独立的，但是内置图片需要定位图片在正文中的位置，所以内置图片和邮件正文是互相依赖的。

发送带附件的邮件可参考JavaMail 发送 html 格式、带附件的邮件。

发送纯文本的邮件可参照 JavaMail 简单案例。

具体例子

EmailHelper, Email 的帮助类，向帮助类提供 SMTP 服务器域名、用户名、密码、发送人邮箱、收件人邮箱、邮件主题、html 格式的内容、图片的路径，便可发送一份内置图片的邮件。在创建 MimeMultipart 时， 需要传入参数 related，并在正文中声明图片的位置。

SendEmailDemo, 演示发送邮件。

EmailHelper.java

 package mail;
 
 import java.util.Properties;
 
 import javax.activation.DataHandler;
 import javax.activation.DataSource;
 import javax.activation.FileDataSource;
 import javax.mail.BodyPart;
 import javax.mail.Message;
 import javax.mail.MessagingException;
 import javax.mail.Multipart;
 import javax.mail.PasswordAuthentication;
 import javax.mail.Session;
 import javax.mail.Transport;
 import javax.mail.internet.AddressException;
 import javax.mail.internet.InternetAddress;
 import javax.mail.internet.MimeBodyPart;
 import javax.mail.internet.MimeMessage;
 import javax.mail.internet.MimeMultipart;
 
 public class EmailHelper {
 
     private String host;
     private String username;
     private String password;
     private String from;
 
     private String to;
     private String subject;
     private String htmlContent;
     private String imagePath;
 
     public EmailHelper(String host, String username, String password, String from) throws AddressException, MessagingException{
         this.host = host;
         this.username = username;
         this.password = password;
         this.from = from;
     }
 
     public void sendWithImage() throws Exception {
 
         Properties props = new Properties();
         props.put("mail.smtp.auth", "true");
         props.put("mail.smtp.host", host);
 
         final String username1 = username;
         final String password1 = password;
 
         Session session = Session.getInstance(props, new javax.mail.Authenticator() {
             protected PasswordAuthentication getPasswordAuthentication() {
                 return new PasswordAuthentication(username1, password1);
             }
         });
 
         Message message = new MimeMessage(session);
 
         message.setFrom(new InternetAddress(from));
 
         message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
 
         message.setSubject(subject);
 
         Multipart multipart = new MimeMultipart("related");
 
         System.out.println(" html ");
         BodyPart htmlPart = new MimeBodyPart();
         htmlContent = "<img src=\"cid:image\">" + htmlContent;
         htmlPart.setContent(htmlContent, "text/html");
         multipart.addBodyPart(htmlPart);
 
         System.out.println(" image ");
         System.out.println("image path : " + imagePath);
         BodyPart imgPart = new MimeBodyPart();
         DataSource fds = new FileDataSource(this.imagePath);
 
         imgPart.setDataHandler(new DataHandler(fds));
         imgPart.setHeader("Content-ID", "<image>");
 
         multipart.addBodyPart(imgPart);
         message.setContent(multipart);
         Transport.send(message);
 
         System.out.println(" Sent -| ");
     }
 
     public void setTo(String to) {
         this.to = to;
     }
 
     public void setSubject(String subject) {
         this.subject = subject;
     }
 
     public void setHtmlContent(String htmlContent) {
         this.htmlContent = htmlContent;
     }
 
     public String getImagePath() {
         return imagePath;
     }
 
     public void setImagePath(String imagePath) {
         this.imagePath = imagePath;
     }
 }

SendEmailDemo.java

 public class SendEmailDemo {
 
     public static void main(){
 
         String host = "smtp.163.com";　　　　　　　　// use your smtp server host
 
         final String username = "sender@163.com"; // use your username
         final String password = "password"; 　　// use your password
 
         String from = "sender@163.com"; 　　　　// use your sender email address
 
         String to = "reciever@foxmail.com";　　// use your reciever email address
         try {
             EmailHelper emailHelper = new EmailHelper(host, username, password, from);
             emailHelper.setTo(to);
             emailHelper.setSubject("subject ttt test");
             emailHelper.setHtmlContent("<h1> This is html </h1>");
             emailHelper.setImagePath("/Users/grs/Documents/Java/mavenEmail/test/src/main/resource/promises.png");
 
             emailHelper.send();
 
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 }

参考资料

JavaMail API - Sending Email With Inline Imagess