[Java] JavaMail 發送帶圖片的 html 格式的郵件

JavaMail 發送的郵件正文和附件是相互獨立的，但是內置圖片需要定位圖片在正文中的位置，所以內置圖片和郵件正文是互相依賴的。

發送帶附件的郵件可參考 JavaMail 發送 html 格式、帶附件的郵件。

發送純文本的郵件可參照 JavaMail 簡單案例。

具體例子

EmailHelper, Email 的幫助類，向幫助類提供 SMTP 服務器域名、用戶名、密碼、發送人郵箱、收件人郵箱、郵件主題、html 格式的內容、圖片的路徑，便可發送一份內置圖片的郵件。在創建 MimeMultipart 時， 需要傳入參數 related，並在正文中聲明圖片的位置。

SendEmailDemo, 演示發送郵件。

 

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 = "[e-mail]"; // use your username
        final String password = "password"; 　　// use your password

        String from = "[e-mail]"; 　　　　// use your sender email address

        String to = "[e-mail]";　　// 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();
        }
    }
}

 

參考資料

JavaMail API - Sending Email With Inline Imagess