[java] How to set MimeBodyPart ContentType to "text/html"?

The program below shows an unexpected return value for HTML multipart MIME type. Why does this program print text/plain and not text/html?

public class Main {
  public static void main(String[] args) throws javax.mail.MessagingException, java.io.IOException {
    javax.mail.internet.MimeBodyPart mime_body_part = new javax.mail.internet.MimeBodyPart();
    mime_body_part.setContent("<h1>foo</h1>", "text/html");
    System.out.println(mime_body_part.getContentType());
  }
}

I have tried numerous alternative ways including setting a ByteArrayDataSource wrapped in a DataHandler, but to no avail. The same thing happens when I try this with a MimeMessage instead of a MimeBodyPart.

To compile and run on Linux:

javac -classpath .:activation.jar:mail.jar Main.java
java -classpath .:activation.jar:mail.jar Main

There is a method setText() which takes 3 arguments :

public void setText(String text, String charset, String subtype)
    throws MessagingException

Parameters:

text - the text content to set
charset - the charset to use for the text
subtype - the MIME subtype to use (e.g., "html")

NOTE: the subtype takes text after / in MIME types so for ex.

• text/html would be html
• text/css would be css
• and so on..

What about using:

mime_body_part.setHeader("Content-Type", "text/html");

In the documentation of getContentType it says that the value returned is found using getHeader(name). So if you set the header using setHeader I guess everything should be fine.

Using "<h1>STRING<h1>".getBytes(); you can create a ByteArrayDataSource with content-type and set setDataHandler in your MimeBodyPart

try:

String html "Test JavaMail API example. <br><br> Regards, <br>Ivonei Jr"
byte[] bytes = html.getBytes(); 
DataSource dataSourceHtml= new ByteArrayDataSource(bytes, "text/html");
MimeBodyPart bodyPart = new MimeBodyPart();
bodyPart.setDataHandler(new DataHandler(dataSourceHtml));

MimeMultipart mimeMultipart = new MimeMultipart();
mimeMultipart.addBodyPart(bodyPart);

For me, I set two times:

(MimeBodyPart)messageBodyPart.setContent(content, text/html)
(Multipart)multipart.addBodyPart(messageBodyPart)
(MimeMessage)msg.setContent(multipart, text/html)

and its been working fine.

Try with this:

msg.setContent(email.getBody(), "text/html; charset=ISO-8859-1");

Don't know why (the method is not documented), but by looking at the source code, this line should do it :

mime_body_part.setHeader("Content-Type", "text/html");

I have used below code in my SpringBoot application.

MimeMessage message = sender.createMimeMessage();
message.setContent(message, "text/html");
MimeMessageHelper helper = new MimeMessageHelper(message);

helper.setFrom(fromAddress);
helper.setTo(toAddress);
helper.setSubject(mailSubject);
helper.setText(mailText, true);

sender.send(message);