spring RestTemplate Downloading a Large File
Example
The getForObject and getForEntity methods of RestTemplate load the entire response in memory. This is not suitable for downloading large files since it can cause out of memory exceptions. This example shows how to stream the response of a GET request.
RestTemplate restTemplate // = ...;
// Optional Accept header
RequestCallback requestCallback = request -> request.getHeaders()
.setAccept(Arrays.asList(MediaType.APPLICATION_OCTET_STREAM, MediaType.ALL));
// Streams the response instead of loading it all in memory
ResponseExtractor<Void> responseExtractor = response -> {
// Here I write the response to a file but do what you like
Path path = Paths.get("some/path");
Files.copy(response.getBody(), path);
return null;
};
restTemplate.execute(URI.create("www.something.com"), HttpMethod.GET, requestCallback, responseExtractor);
Note that you cannot simply return the InputStream from the extractor, because by the time the execute method returns, the underlying connection and stream are already closed.
