HttpURLConnection模擬POST請求

public class HttpUtilTest {
    public String sendPost(String url, String Params) throws IOException {
        OutputStreamWriter out = null;
        BufferedReader reader = null;
        String response = "";
        try {
            URL httpUrl = null; //HTTP URL類 用這個類來建立連線
            //建立URL
            httpUrl = new URL(url);
            //建立連線
            HttpURLConnection conn = (HttpURLConnection) httpUrl.openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setRequestProperty("connection", "keep-alive");
            conn.setUseCaches(false);//設定不要快取
            conn.setInstanceFollowRedirects(true);
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.connect();
            //POST請求
            out = new OutputStreamWriter(
                    conn.getOutputStream());
            out.write(Params);
            out.flush();
            //讀取響應
            reader = new BufferedReader(new InputStreamReader(
                    conn.getInputStream()));
            String lines;
            while ((lines = reader.readLine()) != null) {
                lines = new String(lines.getBytes(), "utf-8");
                response += lines;
            }
            reader.close();
            // 斷開連線
            conn.disconnect();

        } catch (Exception e) {
            System.out.println("傳送 POST 請求出現異常！" + e);
            e.printStackTrace();
        }
        //使用finally塊來關閉輸出流、輸入流
        finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }

        return response;
    }
}