将 JsonArray object 从字符串解析为 java object 返回异常

Question

I want to be able to parse a response from the server into Java object using GSON, this is my code:

public void test() throws IOException {
        Gson gson = new Gson();
        final String uri= BASIC_URL.concat("/?apikey=772f549d&s=prom&y=2020");
        simpleHttpClient = new SimpleHttpClient();
        String response = simpleHttpClient.sendGetRequest(BASIC_URL.concat("/?apikey=772f549d&s=prom&y=2020"), headersMap);
        JsonArray array = JsonHandler.asList(response, "Search");
        Type listType = new TypeToken<List<ImdbClass>>(){}.getType();
        Object obj = array.toString().getClass();
        List<ImdbClass> lists = gson.fromJson(array.toString(), listType);
        ImdbClass imdbClass = gson.fromJson(array.toString(), ImdbClass.class);
}

This is the desired Json Array string needed to be parsed into java object:

[
  {
    "Title": "Killer Prom",
    "Year": "2020",
    "imdbID": "tt10814308",
    "Type": "movie",
    "Poster": "N/A"
  },
  {
    "Title": "Prom Knight",
    "Year": "2020–",
    "imdbID": "tt12143924",
    "Type": "series",
    "Poster": "https://m.media-amazon.com/images/M/MV5BMmRmN2QzMzQtYzdiZS00ZTEzLTg4ODgtYmY1MzBmMTM3ZGIzXkEyXkFqcGdeQXVyMTE1Mjg1MjU2._V1_SX300.jpg"
  }
]

and this is my class to parse into:

public class ImdbClass {

    String Title;
    String Year;
    String imdbID;
    String Type;
    String Poster;

    public ImdbClass(){}
}

But when I get to the last line in my code I get the following error:

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $

although my array is array of objects, what do I miss?

Answer 1

The last line in your code is trying to deserialize from an array to a single object, ie

ImdbClass imdbClass = gson.fromJson(array.toString(), ImdbClass.class);

The exception is telling you that to perform a derserialization from a json string to ImdbClass.class, it wasn't expecting the JSON data to be in array format.

The previous line,

List<ImdbClass> lists = gson.fromJson(array.toString(), listType);

looks like it should've already created you a List of ImdbClass - do you even need the last line? You should be able to iterate the list and access them, eg

for (ImdbClass movie : lists)
{
   // do something with movie
}