With Spring 4.1 and above, you can return pretty much anything (such as pictures, pdfs, documents, jars, zips, etc) quite simply without any extra dependencies. For example, the following could be a method to return a user's profile picture from MongoDB GridFS:
@RequestMapping(value = "user/avatar/{userId}", method = RequestMethod.GET)
@ResponseBody
public ResponseEntity<InputStreamResource> downloadUserAvatarImage(@PathVariable Long userId) {
GridFSDBFile gridFsFile = fileService.findUserAccountAvatarById(userId);
return ResponseEntity.ok()
.contentLength(gridFsFile.getLength())
.contentType(MediaType.parseMediaType(gridFsFile.getContentType()))
.body(new InputStreamResource(gridFsFile.getInputStream()));
}
The things to note:
ResponseEntity with InputStreamResource as a return type
ResponseEntity builder style creation
With this method you dont have to worry about autowiring in the HttpServletResponse, throwing an IOException or copying stream data around.