從服務器接收響應時出錯？

Question

我正在制作一個將一些數據存儲在數據庫中，然后將其檢索的應用程序。 在服務器端，我正在使用PHP，在客戶端端，我已經獲得了獲取輸入並將其傳遞給PHP文件的文件。

new AsyncTask<String, String, String>() {

                JSONParser jsonParser = new JSONParser();
                private ProgressBar pBar;
                private String url_post_pet = "http://192.168.0.13/Android/post_pet.php";

                // JSON Node names
                private static final String TAG_SUCCESS = "success";

                /**
                 * Before starting background thread Show Progress Dialog
                 */
                @Override
                protected void onPreExecute() {
                    super.onPreExecute();
                    //pBar = new ProgressBar();
                    //pBar.setIndeterminate(false);
                    //pBar.setVisibility(View.VISIBLE);
                }

                @Override
                protected String doInBackground(String... args) {
                    // Building Parameters
                    HashMap<String, String> params = new HashMap<>();
                    params.put("name", a);
                    params.put("breed", BREED);
                    params.put("type", TYPE);
                    params.put("images", "Whatever");
                    params.put("description", c);
                    params.put("coords", b);

                    // getting JSON Object
                    // Note that create product url accepts POST method
                    JSONObject json = jsonParser.makeHttpRequest(url_post_pet,
                            "POST", params);
                    // check log cat for response
                    Log.d("Create Response", json.toString());

                    // check for success tag
                    try {
                        int success = json.getInt(TAG_SUCCESS);

                        if (success == 1) {
                            // successfully created product
                            Intent i = new Intent(getApplicationContext(), MainActivity.class);
                            startActivity(i);

                            // closing this screen
                            finish();
                        } else {
                            // failed to create product
                        }
                    } catch (JSONException e) {
                        System.out.println("exception" + e);
                        e.printStackTrace();
                    }
                    System.out.println("nul");
                    return null;
                }

                /**
                 * After completing background task Dismiss the progress dialog
                 **/
                protected void onPostExecute(String file_url) {
                    // dismiss the dialog once done
                    //pBar.dismiss();
                }
            }.execute();

        }
    });
}

另外，我有這個JSONParser：

public class JSONParser {

String charset = "UTF-8";
HttpURLConnection conn;
DataOutputStream wr;
StringBuilder result;
URL urlObj;
JSONObject jObj = null;
StringBuilder sbParams;
String paramsString;

public JSONObject makeHttpRequest(String url, String method,
                                  HashMap<String, String> params) {

    sbParams = new StringBuilder();
    int i = 0;
    for (String key : params.keySet()) {
        try {
            if (i != 0){
                sbParams.append("&");
            }
            sbParams.append(key).append("=")
                    .append(URLEncoder.encode(params.get(key), charset));

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        i++;
    }

    if (method.equals("POST")) {
        // request method is POST
        try {
            urlObj = new URL(url);
            conn = (HttpURLConnection) urlObj.openConnection();
            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Accept-Charset", charset);
            conn.setReadTimeout(10000);
            conn.setConnectTimeout(15000);
            conn.connect();

            paramsString = sbParams.toString();

            wr = new DataOutputStream(conn.getOutputStream());
            wr.writeBytes(paramsString);
            wr.flush();
            wr.close();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    else if(method.equals("GET")){
        // request method is GET

        if (sbParams.length() != 0) {
            url += "?" + sbParams.toString();
        }

        try {
            urlObj = new URL(url);
            conn = (HttpURLConnection) urlObj.openConnection();
            conn.setDoOutput(false);
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Accept-Charset", charset);
            conn.setConnectTimeout(15000);
            conn.connect();

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

    }

    try {
        //Receive the response from the server
        InputStream in = new BufferedInputStream(conn.getInputStream());
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        result = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            result.append(line);
        }

        Log.d("JSON Parser", "result: " + result.toString());
    } catch (IOException e) {
        e.printStackTrace();
    }

    conn.disconnect();

    // try parse the string to a JSON object
    try {
        System.out.println(jObj);
        jObj = new JSONObject(result.toString());
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON Object
    return jObj;
}

這是我每次提交數據時都會遇到的錯誤：

08-26 12：51：08.236 5089-5156 / chtecnologies.myapplication D / JSON解析器：結果：08-26 12：51：08.239 5089-5156 / chtecnologies.myapplication E / JSON解析器：解析數據org.json.JSONException時出錯：輸入結束於08-26 12：51：08.793 5089-5096 / chtecnologies.myapplication W的字符0：藝術：暫停所有線程占用：190.496ms 08-26 12：51：09.245 5089-5096 / chtecnologies.myapplication W / art：暫停所有線程：137.277ms 08-26 12：51：09.267 5089-5156 / chtecnologies.myapplication E / AndroidRuntime：致命例外：AsyncTask＃1進程：chtecnologies.myapplication，PID：5089 java.lang.RuntimeException：在java.util.concurrent.FutureTask的java.util.concurrent.FutureTask.finishCompletion（FutureTask.java:355）的android.os.AsyncTask $ 3.done（AsyncTask.java:304）上執行doInBackground（）時發生錯誤。 setException（FutureTask.java:222）在java.util.concurrent.FutureTask.run（FutureTask.java:242）在android.os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:231）在java.util.concurr ent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1112）at java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:587）at java.lang.Thread.run（Thread.java:818）原因：java .lang.NullPointerException：嘗試在chtecnologies.myapplication.PostPet $ 4 $ 1.doInBackground（PostPet.java:154）的chtecnologies.myapplication.PostPet上對空對象引用調用虛擬方法'java.lang.String org.json.JSONObject.toString（）' .myapplication.PostPet $ 4 $ 1.doInBackground（PostPet.java:118）在android.os.AsyncTask $ 2.call（AsyncTask.java:292）在java.util.concurrent.FutureTask.run（FutureTask.java:237）在Android .os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:231）at java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1112）at java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java： 587）在java.lang.Thread.run（Thread.java:818）

數據已成功進入數據庫，但是JSONParser中似乎有一個問題，即無法獲得PHP文件的結果。

您能告訴我JSONParser文件或其他地方有什么問題嗎？ 這是我第一次在我的應用程序中實現服務器，希望您能為我提供幫助！ 謝謝

Answer 1

您發送數據的方式看起來很糟糕。 如果要在POST中發送數據，請使用HttpURLConnection類的

String postParam = "name=" + a + "&breed=" + BREED + "&type=" + "&images=" +
        Whatever + "&description=" + c + "&coords=" + b;

try {
    URL url = new URL(url);
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();

    connection.setRequestMethod("POST");
    connection.setDoOutput(true);
    connection.setDoInput(true);
    connection.setRequestProperty("Content-type", "application/x-www-form-urlencoded");

    OutputStream os = connection.getOutputStream();
    os.write(postParam.getBytes());
    os.flush();
    os.close();

    // Fetching the response code
    responseCode = connection.getResponseCode();
    Log.d(TAG, "POST Response Code: " + responseCode);
} catch (Exception e) {
    e.printStackTrace();
}

connection.setRequestMethod-設置要使用GET / POST發送數據的方法

connection.setDoOutput（true） -讓您發送輸出

connection.setDoInput（true） -讓您在發送數據后接收輸入（如果有）

希望這能解決您的問題！