以JSON响应（Java-Jersey-ReST）返回文件

Question

I am working on a use case where I am displaying user's messages on a JSP. Details of the flow are:

• All the messages will be shown in a table with icon for attachments
• When the user clicks on attachment, the file should get downloaded.
• If there is more than one attachment, user can select the required one to download.
• The attachments will be stored on the local filesystem and the path for the attachments will be determined by the system.

I have tried to implement by referring to these SO questions:

• Input and Output binary streams using JERSEY?
• Return a file using Java Jersey
• file downloading in restful web services

However, it's not solving my purpose. I have the following questions:

1. Is it possible to send message data (like subject, message, message id, etc) along with the attachments (Inputstream) in one response?
2. If yes, what needs to be the MediaType for @Produces annotation in my resource method? Currently my resource is annotated with @Produces(MediaType.APPLICATION_JSON) . Will this work?
3. How to send the file data in the response?

Any pointers appreciated. TIA.

Answer 1

1. You can add custom data to the response Header, so yes you are able to send such message data. Add the data to the response Header.

2. @Produces(MediaType.APPLICATION_JSON) will not work, unless the clients will accept JSON as a file, what they should and will not do ;)
   

   The correct MediaType depends on what kind of file you want to submit.
   

   You can use the default MediaType / MIME-Type MediaType.APPLICATION_OCTET_STREAM / application/octet-stream ( Is there a “default” MIME type? ) but I think it's better to use the correct and exact MIME-Type for your file.

3. You will find working examples for sending file data with jersey in Input and Output binary streams using JERSEY? - so there is no need to answer this again :)

Hope this was helpful somehow, have a nice day.