Create a Java File object (or equivalent) using a byte array in memory (without a physical file)

Question

I want to create a Java File object in memory (without creating a physical file) and populate its content with a byte array.

Can this be done?

T

Answer 1

Have you tried changing the resource you feed to addInline()? If you wanted the resource to be in memory, I would have tried a org.springframework.core.io.ByteArrayResource.

Update: I think you might need to use the DataSource version of the addInline() method and then use a byte array bound data source object to feed the data into the helper class. I would try the following:

MimeMessage message = mailSender.createMimeMessage();
MimeMessageHelper helper = new MimeMessageHelper(message);              
helper.setFrom("no-reply@example.com", "xyz");
helper.setTo(email);
helper.setText(body,true);
helper.setSubject(subject);

// use javax.mail.util.ByteArrayDataSource
ByteArrayDataSource imgDS = new ByteArrayDataSource( imageByteArr, "image/png");
helper.addInline("cImage", imgDS);

mailSender.send(message);