Json string to Java object Gson

Question

I have a json string in this format :

 [
   {
     "key1": { "key1":"val1","key2":"val2" },
     "key2": { "key1":"val1","key2":"val2" }
   }
]   

To parse it I created a java class :

class data {
     String key;
     List <content> listdata;
     /* getter and setter for the attribute above */
     ...
   } 

Now I followed Gson documentation, and try to exract data :

Gson gson =new Gson();
data[] ints = gson.fromJson(MyjsonString, data[].class); 

I get parsing error from Gson API, what I done wrong ?

java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1 path

Answer 1

For parsing json like following class

class data {
String key;
List <content> listdata;
/* getter and setter for the attribute above */
...
} 

you need a json like as follows

"data" : {
 "key": "value",
 "listdata": [{ content object key attributes here }]
}

As your exception clearly saying BEGIN_ARRAY but was STRING so you have to use array in json for parsing.

In Reply of your comment

If you want a class which parse following json

{
 "key1": { "key1":"val1","key2":"val2" },
 "key2": { "key1":"val1","key2":"val2" }
}

Then you would have classes structure as follows

class Data {
 Map<String, String> key1;
 Map<String, String> key2;
 /* getter and setter for the attribute above */
} 

Answer 2

As per the Json, this class structure works:

class data {
 List <Map<String,Content> data;
 /* getter and setter for the attribute above */
 ...

}