使用 HttpURLConnection 而不是 HttpPost

Question

我有一个用 java 编写的用于 android 应用程序的代码。通过使用 HttpPost 和 DefaultHttpClient 库。目前，我正在重新编码它以用 HttpURLConnection 替换 HttpPost 和 DefaultHttpClient 库，因为 DefaultHttpClient 已被贬低。 我已经为我的一个项目完成了它，并且成功了。

但在当前项目中，使用 HttpURLConnection 而不是 DefaultHttpClient 时，我没有从 web 服务获得相同的响应。谁能帮我解决我做错的地方？

这是旧代码：

DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
String postParameter = "Param1=" + Value1 + "&Param2="+ Value2+ "&Param3="+Value3;
try {
 httpPost.setEntity(new StringEntity(postParameter));
} catch (Exception e) {
 e.printStackTrace();
}
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
xml = EntityUtils.toString(httpEntity);

这是我的新代码

_Url = new URL(Url);
HttpURLConnection urlconnection = (HttpURLConnection) _Url.openConnection();
urlconnection.setRequestMethod(Type);
urlconnection.setConnectTimeout(Timeout);
urlconnection.setUseCaches(false);
urlconnection.setDoInput(true);
urlconnection.setDoOutput(true);
 String postParameter = "Param1=" + Value1 + "&Param2="+ Value2+ "&Param3="+Value3;
BufferedWriter writer = new BufferedWriter( new OutputStreamWriter(os));
writer.write(postParameter);
writer.flush();
writer.close();
os.close();
urlconnection.connect();

代码运行没有任何错误，但 web 服务给出的响应与旧代码不同。

Answer 1

你没有得到输入流，试试下面的代码

         try {

                String postParameter = "Param1=" + Value1 + "&Param2="+ Value2+ "&Param3="+Value3;
                URL url = new URL(UrlStr);
                HttpURLConnection urlConnection = (HttpURLConnection) url
                        .openConnection();
                urlConnection.setRequestMethod("POST");
                urlConnection.setRequestProperty("Accept",
                        "application/json");
                urlConnection.setRequestProperty("Content-Type",
                        "application/json");// setting your headers its a json in my case set your appropriate header

                urlConnection.setDoOutput(true);
                urlConnection.connect();// setting your connection

                OutputStream os = null;
                os = new BufferedOutputStream(
                urlConnection.getOutputStream());
                os.write(postParameter.toString().getBytes());
                os.flush();// writing your data which you post


                StringBuffer buffer = new StringBuffer();
                InputStream is = urlConnection.getInputStream();
                BufferedReader br = new BufferedReader(
                        new InputStreamReader(is));
                String line = null;
                while ((line = br.readLine()) != null)
                    buffer.append(line + "\r\n");
                     // reading your response 

                is.close();
                urlConnection.disconnect();// close your connection
                return buffer.toString();

            } catch (Exception e) {
            }

Answer 2

试试这个

List nameValuePairs = new ArrayList(3);
            nameValuePairs.add(new BasicNameValuePair("Param1", value1));
            nameValuePairs.add(new BasicNameValuePair("Param2", value2));
            nameValuePairs.add(new BasicNameValuePair("Param3", value3));

            UrlEncodedFormEntity entity = new UrlEncodedFormEntity(nameValuePairs);

OutputStream post = request.getOutputStream();
            entity.writeTo(post);
            post.flush();