为什么 JSON 文档没有被完全消耗？

Question

我正在尝试从外部来源检索 JSON 数据以进行练习。我已准备好所有代码，但由于某种原因，我收到一条错误消息，指出该文档未完全使用。我已经观看并阅读了多个教程和指南，但似乎仍然无法正确理解。我还搜索了堆栈以寻找答案，但由于我不知道出了什么问题，所以我真的不知道要寻找什么。

代码全部到位，没有明显的过错。JSON 数据已经过验证，它可以作为原始 JSON 数据进行检索，如日志中所示。当数据应该传输到 java 数据类时，问题发生在 Gson 转换中。任何想法可能是错误的？

public class JSONimport extends AsyncTask<Void, Void, DeserializedContainer> {

private static final String TAG = "TAG";

//VARIABLES TO HOLD JSON DATA
private OnLoadListener mListener;


//CONSTRUCTOR
public JSONimport(OnLoadListener listener) {
    this.mListener = listener;
}

//ASYNK, DO IN BACKGROUND THREAD
@Override
protected DeserializedContainer doInBackground(Void... voids) {
    String myJSON = ""; //TEMP VARIABLE TO HOLD JSON DATA
    String completeJSONdata = ""; //VARIABLE TO HOLD COMPLETE JSON DATA

    try {
        URL urlObject = new URL( "https://api.myjson.com/bins/161kkd" );
        HttpURLConnection httpURLConnection = (HttpURLConnection) urlObject.openConnection();
        InputStream inputStreamObject = httpURLConnection.getInputStream();
        BufferedReader bufferedReaderObject = new BufferedReader( new InputStreamReader( inputStreamObject ) );

        while (myJSON != null) {
            myJSON = bufferedReaderObject.readLine();
            completeJSONdata += myJSON;
        }

    } catch (MalformedURLException e) {
        e.printStackTrace();
        Log.d( TAG, "doInBackground: ERROR RETRIEVING URL" );
    } catch (IOException e) {
        e.printStackTrace();
        Log.d( TAG, "doInBackground: ERROR HTTP CONNECTION" );
    }


    //DESERIALIZATION, converting JSON to java variables, making the data easy to handle
    Gson gsonObject = new GsonBuilder()
            .setLenient()
            .create();
    DeserializedContainer deserializedContainerObject;

    deserializedContainerObject = gsonObject.fromJson( completeJSONdata, DeserializedContainer.class );
    //Log.d( TAG, "doInBackground: " + deserializedContainerObject.getDeserializedContainerList() );


    return deserializedContainerObject;
}

@Override
protected void onPostExecute(final DeserializedContainer result) {

    mListener.onSuccess( result );
    //FUNKAR ATT HÄMTA JSON DATA. KOLLA LOGCAT
    Log.d( TAG, "onPostExecuteLOL: " + result );
}

public static interface OnLoadListener {
    void onSuccess(DeserializedContainer container);
}}

错误在 deserializedContainerObject = gsonObject.fromJson( completeJSONdata, DeserializedContainer.class );

保存 JSON 数据的数据对象：

public class DeserializedContainer {
@SerializedName("deserializedContainerList")
public List<DeserializedVariables> deserializedContainerList = new ArrayList<>();

public List<DeserializedVariables> getDeserializedContainerList() {
    return deserializedContainerList;
}}

public class DeserializedVariables {
@SerializedName( "movieName" )
private String movieName;
@SerializedName( "movieYear" )
private int movieYear;
@SerializedName( "movieRating" )
private double movieRating;}

来自主线程的相关数据：

public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.activity_main );

    //BACKGROUND THREAD
    JSONimport jsonImportObject = new JSONimport( new JSONimport.OnLoadListener() {
        @Override
        public void onSuccess(DeserializedContainer container) {
            container.getDeserializedContainerList();
        }
    } );
    jsonImportObject.execute();

    //Log.d( TAG, "onCreateGETTING DATA : " + jsonImportObject.getCompletedData());

    DeserializedContainer deserializedContainerObject = new DeserializedContainer();
    Log.d( TAG, "onCreate: " + deserializedContainerObject);

JSON：

{"deserializedContainerList":[{"movieName":"filmA","movieYear":2017,"movieRating":4.7},{"movieName":"filmB","movieYear":2018,"movieRating":4.8}, {"movieName":"filmC","movieYear":2019,"movieRating":4.9}]}

抱歉发了这么长的帖子，希望你有精力看完。我真的被困住了。我知道 Retrofit 和类似的库，但我已经花了很多时间来解决这个问题，我还不想放弃它：P

谢谢！

/////// 更新 /////// 我根据 Laurent B 的建议更新了代码，并且成功了！或者，至少它没有崩溃。我尝试使用以下代码在主线程上打印列表：

for(int i = 0; i < deserializedContainerObject.deserializedContainerList.size(); i++) {
        Log.d( TAG, "onCreate: " + deserializedContainerObject.deserializedContainerList.get( i ));

    }

但什么也没显示。检查 deserializedContainerObject.deserializedContainerList.size() 时，它显示为 0。也就是说，没有数据添加到列表中......嗯。至少它不会崩溃，多亏了Laurent B，所以更近了一步。

Answer 1

该值正在被传递，但是 null 也随之传递，因此使用 if 语句而不是像这样使用 while 。

if (myJSON != null) {
                myJSON = bufferedReaderObject.readLine();
                completeJSONdata += myJSON;
            }

然后像这样转换成Gson..

    Gson gson = new Gson();
    deserializedContainerObject = gson.fromJson(completeJSONdata, DeserializedContainer.class);

DeserializedVariables在类中编写 getter 和 setter

public String getMovieName() {
         return movieName;
     }

     public void setMovieName(String movieName) {
         this.movieName = movieName;
     }

     public Integer getMovieYear() {
         return movieYear;
     }

     public void setMovieYear(Integer movieYear) {
         this.movieYear = movieYear;
     }

     public Double getMovieRating() {
         return movieRating;
     }

     public void setMovieRating(Double movieRating) {
         this.movieRating = movieRating;
     }

现在你可以onPostExecute()像这样检索它..

@Override
    protected void onPostExecute( DeserializedContainer result) {

        mListener.onSuccess( result );

        for (int i = 0; i <result.deserializedContainerList.size(); i++) {
            DeserializedVariables deserializedVariables = result.deserializedContainerList.get(i);
            Log.d( TAG, "onPostExecuss: " + deserializedVariables.getMovieName() );
        }

    }