Question

我正在创建一个将数据存储在数据库中的应用程序，然后检索它。在服务器端，我正在使用PHP，在客户端，我有这个文件获取输入并将其传递给PHP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，我有这个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;
}

这是我每次提交数据时都会遇到的错误：

08-26 12:51:08.236 5089-5156 / chtecnologies.myapplication D / JSON解析器：结果：08-26 12：51：08.239 5089-5156 / chtecnologies.myapplication E / JSON解析器：解析数据组织时出错。 json.JSONException：字符0的输入结束 08-26 12:51:08.793 5089-5096 / chtecnologies.myapplication W / art：暂停所有线程：190.496ms 08-26 12:51:09.245 5089-5096 / chtecnologies.myapplication W / art：暂停所有线程：137.277ms 08-26 12:51:09.267 5089-5156 / chtecnologies.myapplication E / AndroidRuntime：致命异常：AsyncTask＃1 过程：chtecnologies.myapplication，PID：5089 java.lang.RuntimeException：执行doInBackground（）时发生错误在android.os.AsyncTask $ 3.done（AsyncTask.java:304）在java.util.concurrent.FutureTask.finishCompletion（FutureTask.java:355） at java.util.concurrent.FutureTask.setException（FutureTask.java:222）在java.util.concurrent.FutureTask.run（FutureTask.java:242）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）引发者：java.lang.NullPointerException：尝试在空对象引用上调用虚方法'java.lang.String org.json.JSONObject.toString（）' 在chtecnologies.myapplication.PostPet $ 4 $ 1.doInBackground（PostPet.java:154）在chtecnologies.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）

数据成功进入数据库，但JSONParser中似乎存在问题，而无法获取PHP文件的结果。

您是否会告诉我JSONParser文件或其他地方是否有任何错误？这是我第一次在我的应用程序中实现服务器，希望你能帮助我！谢谢

Answer 1

您发送数据的方式看起来很可疑。如果您想在POST中发送数据，请使用HttpURLConnection，如

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 - 设置您希望使用GET / POST发送数据的方法

connection.setDoOutput（true） - 让您发送输出

connection.setDoInput（true） - 让您在发送数据后接收输入（如果有的话）

希望这能解决您的问题！

从服务器接收响应时出错？

1 个答案: