JSONException疑难解答:字符0 Android处的输入结束

Question

我遇到错误JSONException的问题。 我的doInBackground((将movieId的参数(1(已经记录(传递给php文件，然后PHP文件将执行查询并返回json。在浏览器中运行适用于 JSON 响应。

import android.app.ProgressDialog;
import android.net.ParseException;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.bumptech.glide.Glide;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Text;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

/**
 * A simple {@link Fragment} subclass.
 */
public class FirstFragment extends Fragment {
    ImageView imageView;
    TextView name, id;
    public FirstFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        final View rootView =  inflater.inflate(R.layout.fragment_first, container, false);
        imageView = (ImageView) rootView.findViewById(R.id.movie_image);
        name = (TextView) rootView.findViewById(R.id.movie_name);
        id = (TextView) rootView.findViewById(R.id.movie_id);
        Bundle mBundle = new Bundle();
        mBundle = getArguments();
        name.setText(mBundle.getString("textMovieName"));
        id.setText(mBundle.getString("textMovieId"));

        Glide.with(getContext()).load(mBundle.getString("ivMovie"))
                .placeholder(R.drawable.placeholder)
                .error(R.drawable.ic_menu_camera)
                .into(imageView);
        new AsyncDate().execute(mBundle.getString("textMovieId"));
        return rootView;
    }
    private class AsyncDate extends AsyncTask<String, String, String> {
        ProgressDialog pdLoading = new ProgressDialog(getActivity());
        HttpURLConnection conn;
        URL url = null;
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }
        @Override
        protected String doInBackground(String... params) {
            try {
                url = new URL("http://100.74.245.14/finalproject/date_time.php");
            } catch (MalformedURLException e) {
                e.printStackTrace();
                return "exception";
            }
            //Log.d("params", params[0]);
            try {
                conn = (HttpURLConnection) url.openConnection();
                conn.setReadTimeout(10000);
                conn.setConnectTimeout(10000);
                conn.setRequestMethod("POST");
                conn.setDoInput(true);
                conn.setDoOutput(true);
                Uri.Builder builder = new Uri.Builder()
                        .appendQueryParameter("movieId", params[0]);
                String query = builder.build().getEncodedQuery();
                OutputStream os = conn.getOutputStream();
                BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
                writer.write(query);
                writer.flush();
                writer.close();
                os.close();
                conn.connect();
            } catch (IOException e1) {
                e1.printStackTrace();
                return "exception";
            }
            try {
                int response_code = conn.getResponseCode();
                if (response_code == HttpURLConnection.HTTP_OK) {
                    //Log.d("response","ok");
                    InputStream input = conn.getInputStream();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(input));
                    StringBuilder result = new StringBuilder();
                    String line;
                    while ((line = reader.readLine()) != null) {
                        result.append(line);
                    }
                    Log.d("return", result.toString());
                    return (result.toString());
                } else {
                    return "unsuccessful";
                }
            } catch (IOException e2) {
                e2.printStackTrace();
                return "exception";
            } finally {
                conn.disconnect();
            }
        }
        @Override
        protected void onPostExecute(String result) {
            List<listMovie> data = new ArrayList<>();
            try {
                JSONObject jsonObj = new JSONObject(result);
                JSONArray jArray = jsonObj.getJSONArray("test");
                //Log.d("json", result);
                for (int i = 0; i < jArray.length(); i++) {
                    //Log.d("json", "test");
                    JSONObject json_data = jArray.getJSONObject(i);
                    listMovie movieData = new listMovie();
                    movieData.movieDate = json_data.getString("date");
                    movieData.movieTime = json_data.getString("time");
                    data.add(movieData);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }
}

PHP 文件

<?php
include 'config.inc.php';
if(isset($_POST['movieId'])) {
    $movieId= $_POST['movieId'];

    $sql = 'SELECT * FROM movie_time WHERE movie_id = :movie_id';
    $stmt = $conn -> prepare($sql);
    $stmt -> bindParam(':movie_id', $movieId, PDO::PARAM_STR);
    $result = $stmt -> execute();
    if($result) {
        while($row = $stmt->fetchAll(PDO::FETCH_ASSOC)) {
            $flag['test'] = $row;
        }
    header('Content-type: application/json');
    echo json_encode($flag);
    }
}

?>

我得到的错误

W/System.err: org.json.JSONException: End of input at character 0 of 
W/System.err:     at org.json.JSONTokener.syntaxError(JSONTokener.java:450)
W/System.err:     at org.json.JSONTokener.nextValue(JSONTokener.java:97)
W/System.err:     at org.json.JSONObject.<init>(JSONObject.java:155)
W/System.err:     at org.json.JSONObject.<init>(JSONObject.java:172)
W/System.err:     at com.example..fyp.FirstFragment$AsyncDate$override.onPostExecute(FirstFragment.java:153)
W/System.err:     at com.example.fyp.FirstFragment$AsyncDate$override.access$dispatch(FirstFragment.java)
W/System.err:     at com.example.fyp.FirstFragment$AsyncDate.onPostExecute(FirstFragment.java:0)
W/System.err:     at com.example.fyp.FirstFragment$AsyncDate.onPostExecute(FirstFragment.java:75)
W/System.err:     at android.os.AsyncTask.finish(AsyncTask.java:632)
W/System.err:     at android.os.AsyncTask.access$600(AsyncTask.java:177)
W/System.err:     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
W/System.err:     at android.os.Looper.loop(Looper.java:136)
W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5017)
W/System.err:     at java.lang.reflect.Method.invokeNative(Native Method)
W/System.err:     at java.lang.reflect.Method.invoke(Method.java:515)
W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
W/System.err:     at dalvik.system.NativeStart.main(Native Method)

在这一行

JSONObject jsonObj = new JSONObject(result);

Answer 1

很难确定这一点，但我敢打赌，在打开/关闭 php 标签之前/之后，您有一些空格或换行符。

检查 php 打开标签 (<？php( 是否是 php 文件中的第一个字符，并删除结束 php 标签。

Answer 2

您将movie_id参数作为URL查询参数(在Java代码中(附加，但在PHP $_POST数组中查找：这是行不通的。

要么更改你的PHP以同时查看$_POST和$_GET，要么改变你的Java以实际执行正确的POST请求。

另外，作为旁注，您可能只想在doInBackground内执行new JSONObject()调用：在后台线程上进行 JSON 解析并在执行中处理解析的对象更有效。

编辑：您可能还想设置内容类型标头(尝试conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");