[Android] HttpUrlConnection 사용하기

public class HttpUrlConnection {
 
    public String performPostCall(String requestUrl, HashMap<String, String> postDataParams){
        URL url;
        String respones = "";
 
        try{
            url = new URL(requestUrl);
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setReadTimeout(15000);
            conn.setConnectTimeout(15000);
            conn.setRequestMethod("GET");
            conn.setDoInput(true);
            conn.setDoOutput(true);
 
            OutputStream os = conn.getOutputStream();
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
            writer.write(getPostDataString(postDataParams));
            writer.flush();
            writer.close();
            os.close();
            int responseCode = conn.getResponseCode();
 
            if(responseCode == HttpURLConnection.HTTP_OK){
                String line;
                BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
 
                while ((line = br.readLine()) != null){
                    respones += line;
                }
            }else{
                respones = "";
            }
        }catch(Exception e){
            e.printStackTrace();
        }
        Log.e("TEST", "ResPonse > "+respones);
        return respones;
    }
 
    private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException{
        StringBuilder result = new StringBuilder();
        boolean first = true;
        for(Map.Entry<String, String> entry : params.entrySet()){
            if(first)
                first = false;
            else
                result.append("&");
 
            result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
        }
        Log.e("TEST", "In Params > "+result.toString());
        return result.toString();
    }
 
}