How to deserialize a JSON array of objects using Gson library?

Question

I am facing an issue while I am trying to deserialize a JSON array of objects using the Gson library.

An example of the JSON array:

[
    {"ID":1,"Title":"Lion","Description":"bla bla","ImageURL":"http:\/\/localhost\/lion.jpg"},
    {"ID":1,"Title":"Tiger","Description":"bla bla","ImageURL":"http:\/\/localhost\/tiger.jpg"}
]

What do you think? What is the proper Java code to deserialize such a JSON response?

Is there more direction you can provide about the problem? What is the input, where are you getting it from, what are you trying? — Michael, Apr 24 '12 at 06:08
The Proplem is when I try to get a Objcet[] array usin gson.fromJson() I get a null vule , I get this JSON array from a PHP page : — Nashwan D, Apr 24 '12 at 06:26

score 56 · Accepted Answer · answered Apr 24 '12 at 06:32

56

To deserialize a JSONArray you need to use TypeToken. You can read more about it from GSON user guide. Example code:

@Test
public void JSON() {
    Gson gson = new Gson();
    Type listType = new TypeToken<List<MyObject>>(){}.getType();
    // In this test code i just shove the JSON here as string.
    List<Asd> asd = gson.fromJson("[{'name':\"test1\"}, {'name':\"test2\"}]", listType);
}

If you have a JSONArray then you can use

...
JSONArray jsonArray = ...
gson.fromJson(jsonArray.toString(), listType);
...

answered Apr 24 '12 at 06:32

Kirstein

893
8
10

1

what is List asd here? – Seenu69 Aug 21 '14 at 06:44
Can anyone help me with this - http://stackoverflow.com/questions/27666558/deserializing-json-array-using-gson ? – Ram Patra Dec 27 '14 at 12:33
4

FYI, for Type is java.lang.reflect.Type. There're million Type classes so auto complete might be confusing. – Nativ Mar 02 '16 at 21:36
If the JsonArray is of a known type the best way might be http://stackoverflow.com/questions/43133484/deserializing-a-jsonarray-of-doubles – Roland Mar 31 '17 at 06:05
THis doesn't seem to work. "Asd" is not defined. – John Little Jul 19 '21 at 09:49

score 0 · Answer 2 · answered Jan 26 '23 at 07:13

For example your service has such response

[ new SomeObject(), new SomeObject(), new SomeObject() ] - this is jsonArray

SomeObject - is a class instance of that your array is contains.

You should use special class TypeToken (docs here https://sites.google.com/site/gson/gson-user-guide)

Type type = new TypeToken<List<SomeObject>>(){}.getType();



String jsonArray = restResponse.getPayload(); - you get response as String
List<SomeObject > list = new Gson().fromJson(jsonArray, type);

Done!

How to deserialize a JSON array of objects using Gson library?

2 Answers2

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