Java – how to send a post request and get a file response?

I want to send post requests (such as HTML forms) and get files (HTTP Title: "content disposition: attachment; filename =" myfile. PDF "). Can you help me?

Solution

Your best choice may be to use a third-party library, such as httpclient or htmlunit

If you prefer to use standard APIs, it's less complicated

// Construct data
String data = URLEncoder.encode("key1","UTF-8") + "=" + 
                                URLEncoder.encode("value1","UTF-8");

data += "&" + URLEncoder.encode("key2","UTF-8") + "=" +
                                URLEncoder.encode("value2","UTF-8");

// Send data
URL url = new URL("http://hostname:80/cgi");
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write(data);
wr.flush();

// Get the response
BufferedReader rd = new BufferedReader(
        new InputStreamReader(conn.getInputStream()));

String line;
while ((line = rd.readLine()) != null) {
    // Process line...
}
wr.close();
rd.close();