Android HttpUrlConnection 不起作用

Question

基本上，我正在尝试通过 Android 应用程序连接到网络界面。

我设法使用 HttpClient 成功地将命令发送到表单。但是，我想按照此处http://android-developers.blogspot.com/2011/09/androids-http-clients.html 的建议使用 HttpUrlConnection 来完成此操作，以实现更快、更节能的连接。

URL url = new URL("http://" + mIpAddress + ":" + mPort + "/command.html");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setReadTimeout(10000);
connection.setConnectTimeout(15000);
connection.setRequestMethod("POST");
connection.setDoInput(true);
connection.setDoOutput(true);

OutputStream os = connection.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(URLEncoder.encode("parameter=" + value, "UTF-8");
writer.flush();
writer.close();
os.close();

connection.connect();

编辑：没有抛出异常，因为代码执行得很好，请求可能不是服务器预期的格式？

Answer 1

connnection.getInputStream() 是 POST 工作所必需的。固定。

Answer 2

这是我用来使用 HttpURLConnection 发送 http 请求的方法，请注意 connection.connect() 是在设置 HttpURLConnection 之后而不是最后，setDoInput 也使请求 POST 而不是默认的 get，

    URL url = new URL(urlString);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    //conn.setReadTimeout(10000 /* milliseconds */);
    // conn.setConnectTimeout(15000 /* milliseconds */);
    //conn.setRequestMethod("GET");
    //conn.setDoInput(true);   //* uses POST
    // Starts the query
    conn.connect();
    InputStream stream = conn.getInputStream();
    //String data = convertStreamToString(stream);
    int sz = stream.available();
    byte[] b = new byte[sz];
    stream.read(b);
    stream.close();
    String data = new String(b);

Answer 3

只需添加一行

connection.getRequestMethod();

它会起作用的。

我不知道为什么，但是在我花了一整天的时间后，这对我有用！

Answer 4

您能否提供更多信息，例如异常或服务器响应？服务器收到你的请求了吗？

但是，我建议您使用在HttpUrlConnection 之上构建的okhttp

Answer 5

使用 HttpUrlConnection 类共享数据 这是 Simple Connection 类，它将帮助您与 WS 连接，并使用 JSON 解析传递数据..

import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class CommonConnectionClass {
    JSONObject jsonObject;
    public JSONObject getConnection(String u,JSONObject object){
        try {

            //URL url=new URL("https://e-gurukulam.000webhostapp.com/public_html/project/login.php"+u+".php");
            URL url=new URL("http://"+new Connection_Url_Setter().urlIp+"/classroom/"+u+".php");
           // URL url=new URL("http://192.168.43.120/classroom/"+u+".php");
            HttpURLConnection httpURLConnection=(HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setRequestProperty("Content-Type","application/json; charset=utf-8");
            httpURLConnection.setRequestProperty("Accept","application/json; charset=utf-8");
            httpURLConnection.setDoInput(true);
            httpURLConnection.setDoOutput(true);
            httpURLConnection.connect();

            if(object!=null) {
                DataOutputStream dataOutputStream = new DataOutputStream(httpURLConnection.getOutputStream());
                dataOutputStream.write(object.toString().getBytes());

            }
            int code=httpURLConnection.getResponseCode();
            if(code== HttpURLConnection.HTTP_OK){
                String inputLine;
                StringBuilder stringBuilder=new StringBuilder();


                BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
                while((inputLine=bufferedReader.readLine())!=null){
                    stringBuilder.append(inputLine);
                }
                jsonObject=new JSONObject(stringBuilder.toString());
            }


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


        return jsonObject;
    }
}

要使用这个类，我使用 Asyn 类 Like,...

class userNameFetchTask extends AsyncTask<Void, Void, JSONObject> {
            JSONObject object, jsonObject, json;
            JSONArray jsonArray;
            ArrayList<CreateGroupModel> lidList = new ArrayList<>();
            String lid, name;

            @Override
            protected void onPreExecute() {
                jsonObject = new JSONObject();
                try {
                    jsonObject.put("lid", sp.getString("lid", null));
                } catch (JSONException e) {
                    e.printStackTrace();
                }
                super.onPreExecute();
            }

            @Override
            protected JSONObject doInBackground(Void... voids) {
                object = new JSONObject();
                CommonConnectionClass commonConnectionClass = new CommonConnectionClass();
                object = commonConnectionClass.getConnection("selectUserForGroup", jsonObject);
                return object;
            }

            @Override
            protected void onPostExecute(JSONObject jsonObject) {
                super.onPostExecute(jsonObject);
                jsonArray = new JSONArray();
                try {
                    jsonArray = jsonObject.getJSONArray("response");
                    for (int i = 0; i < jsonArray.length(); i++) {

                        CreateGroupModel model = new CreateGroupModel();

                        json = jsonArray.getJSONObject(i);
                        model.setLid(json.getString("relative_lid"));
                        model.setName(json.getString("name"));
                        model.setEmail(json.getString("email"));
                        model.setImage(json.getString("image"));

                        lidList.add(model);
                    }
                    viewstudentsadapterForCreateGroup viewstudentsadapterForCreateGroup = new viewstudentsadapterForCreateGroup(getApplicationContext(), lidList, createGroup_Activity.this);
                    listView.setAdapter(viewstudentsadapterForCreateGroup);

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

Answer 6

在我的例子中，它实际上是抛出 ​​NetworkOnMainThreadException 但在日志中没有清楚地显示