Question

How to download an image from a server and then write it as a response in my servlet.
What is the best way to do it keeping good performance?

Here’s my code:

JSONObject imageJson;
... //getting my JSON
String imgUrl = imageJson.get("img");

Answer 1

It’s important to avoid intermediate buffering of image in servlet. Instead just stream whatever was received to the servlet response:

InputStream is = new URL(imgUrl).openStream();
OutputStream os = servletResponse.getOutputStream();

IOUtils.copy(is, os);
is.close();

I’m using IOUtils from Apache Commons (not necessary, but useful).