How to get a binary stream by GridFS ObjectId with Spring Data MongoDB

Question

I can\'t figure out how to stream a binary file from GridFS with spring-data-mongodb and its GridFSTemplate when I already have the right ObjectId.

Answer 1

Spring Data 2.1.0 added an overload of getResource() to GridFsTemplate that returns the GridFsResource for a given GridFsFile. GridFsResource has a method to get the InputStream. Therefore, if you're on at least this version of Spring Data, you can get the InputStream by making two calls to the GridFsTemplate:

GridFSFile file = gridFsTemplate.findOne(Query.query(Criteria.where("_id").is(id)));

// In real code, make sure you perform any necessary null checks if the file doesn't exist

GridFsResource resource = gridFsTemplate.getResource(gridFsFile);
InputStream inputStream = resource.getInputStream();