How to make jira attachments download work using jira rest api - download

Question

I am trying to download attachments from Jira. I use /rest/api/2/attachment/{id} to get json response of the attachment. It has field "content" that is the attachment url. I use this url and construct HttpGet and execute to get response that always gives me html content asking for login. I am sending Basic Authorization in the httpGet header. Apparently this works for downloading .png files but not any other file types. I am using java spring rest to connect to Jira horizon.
Closeable httpclient = HttpClients.createDefault();
HttpGet httpGet = new HttpGet(jira attachmenturl);
httpGet.setHeader("Authorization", "Basic <base64Credentials>);
CloseableHttpResponse response = httpclient.execute(httpGet)
The response for .txt, .jpeg, Microsoft documents is different from response that I get for .png files.

Answer 1

This works:
#GetMapping(value = "/getAttachment")
public String getAttachment(#RequestParam("id") String attachmentID) throws Exception {
Client client = Client.create();
WebResource webResource = client.resource(jiraBaseURLRest + "attachment/" +
attachmentID);
ClientResponse response = webResource.header("Authorization", "Basic " +
base64Creds).type("application/json")
.accept("application/json").get(ClientResponse.class);
String result = response.getEntity(String.class);
JSONObject jsonObj = new JSONObject(result);
System.out.println("JSON Object = "+jsonObj);
URL url = new URL(jsonObj.getString("content"));
Closeable httpclient = HttpClients.createDefault();
HttpGet httpGet = new HttpGet(url.toURI());
httpGet.setHeader("Authorization", "Basic " + base64Creds);
CloseableHttpResponse response1 = ((CloseableHttpClient) httpclient).execute(httpGet);
if(response1.getStatusLine().getStatusCode() == 200)
{
HttpEntity entity = response1.getEntity();
if (entity.isStreaming())
{
System.out.println("Streaming...");
byte data[] = EntityUtils.toByteArray(entity);
FileOutputStream fout = new FileOutputStream(new File("D://pdf1.pdf"));
fout.write(data);
fout.close();
System.out.println("Done!!");
}
}
return "Success";
}