JSONException 故障排除：在字符 0 Android 处输入结束

Posted 2023-05-07

【中文标题】JSONException 故障排除：在字符 0 Android 处输入结束

【英文标题】：Troubleshooting JSONException: End of input at character 0 Android

【发布时间】：2017-08-17 23:01:19

【问题描述】：

我遇到错误 JSONException 的问题。我的 doInBackground() 将 movieId 的参数（即 1（已记录））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);

【参考方案1】：

很难确定这一点，但我敢打赌，您在打开/关闭 php 标记之前/之后会有一些空格或换行符。

检查 php 打开标记 (

【参考方案2】：

您将 movie_id 参数附加为 URL 查询参数（在您的 Java 代码中），但在 PHP $_POST 数组中查找：这是行不通的。

要么更改您的 PHP 以同时查看 $_POST 和 $_GET，要么更改您的 Java 以实际执行正确的 POST 请求。

另外，附带说明一下，您可能只想在 doInBackground 内调用 new JSONObject()：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");