How to send POST request and get file response?

I want to send POST request (like html form) and get file (HTTP header: "Content开发者_StackOverflow-Disposition: attachment; filename="myfile.pdf"). Can you help me?

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Your best option is probably to use a third party library such as HttpClient or HTMLUnit.

If you prefer to do it with the standard API it's not that 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();

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Check out HttpClient. There's a pretty comprehensive tutorial here.