我想我找到了你需要的东西。它可能会帮助其他人。

你可以使用UrlEncodedFormEntity.writeTo(OutputStream)方法。

UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(nvp); 
http.connect();

OutputStream output = null;
try {
  output = http.getOutputStream();    
  formEntity.writeTo(output);
} finally {
 if (output != null) try { output.close(); } catch (IOException ioe) {}
}

使用PrintWriter有一个更简单的方法(见这里)

基本上你所需要的是:

// set up URL connection
URL urlToRequest = new URL(urlStr);
HttpURLConnection urlConnection = (HttpURLConnection)urlToRequest.openConnection();
urlConnection.setDoOutput(true);
urlConnection.setRequestMethod("POST");
urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

// write out form parameters
String postParamaters = "param1=value1&param2=value2"
urlConnection.setFixedLengthStreamingMode(postParameters.getBytes().length);
PrintWriter out = new PrintWriter(urlConnection.getOutputStream());
out.print(postParameters);
out.close();

// connect
urlConnection.connect();

因为NameValuePair已弃用。想过分享我的代码

public String  performPostCall(String requestURL,
            HashMap<String, String> postDataParams) {

        URL url;
        String response = "";
        try {
            url = new URL(requestURL);

            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setReadTimeout(15000);
            conn.setConnectTimeout(15000);
            conn.setRequestMethod("POST");
            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 == HttpsURLConnection.HTTP_OK) {
                String line;
                BufferedReader br=new BufferedReader(new InputStreamReader(conn.getInputStream()));
                while ((line=br.readLine()) != null) {
                    response+=line;
                }
            }
            else {
                response="";

            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return response;
    }

....

  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"));
        }

        return result.toString();
    }

我使用的方法是这样的:

SchemeRegistry sR = new SchemeRegistry();
sR.register(new Scheme("https", SSLSocketFactory.getSocketFactory(), 443));

HttpParams params = new BasicHttpParams();
SingleClientConnManager mgr = new SingleClientConnManager(params, sR);

HttpClient httpclient = new DefaultHttpClient(mgr, params);

HttpPost httppost = new HttpPost(url);
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

HttpResponse response = httpclient.execute(httppost);

AsyncTask通过POST方法将数据作为JSONObect发送

public class PostMethodDemo extends AsyncTask<String , Void ,String> {
        String server_response;

        @Override
        protected String doInBackground(String... strings) {
            URL url;
            HttpURLConnection urlConnection = null;

            try {
                url = new URL(strings[0]);
                urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setDoOutput(true);
                urlConnection.setDoInput(true);
                urlConnection.setRequestMethod("POST");

                DataOutputStream wr = new DataOutputStream(urlConnection.getOutputStream ());

                try {
                    JSONObject obj = new JSONObject();
                    obj.put("key1" , "value1");
                    obj.put("key2" , "value2");

                    wr.writeBytes(obj.toString());
                    Log.e("JSON Input", obj.toString());
                    wr.flush();
                    wr.close();
                } catch (JSONException ex) {
                    ex.printStackTrace();
                }
                urlConnection.connect();

                int responseCode = urlConnection.getResponseCode();

                if(responseCode == HttpURLConnection.HTTP_OK){
                    server_response = readStream(urlConnection.getInputStream());
                }

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            Log.e("Response", "" + server_response);
        }
    }

    public static String readStream(InputStream in) {
        BufferedReader reader = null;
        StringBuffer response = new StringBuffer();
        try {
            reader = new BufferedReader(new InputStreamReader(in));
            String line = "";
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return response.toString();
    }

JSONObject params = new JSONObject();
try {
   params.put(key, val);
}catch (JSONException e){
   e.printStackTrace();
}

这就是我如何通过POST传递“params”(JSONObject)

connection.getOutputStream().write(params.toString().getBytes("UTF-8"));