Parsing json to a string in Gson

Question

I have a json string:

 {  
   "id":123,
   "name":"",
   "details":{}
}

I want to parse to this object:

class Student {

int id;
String name; 
String details;

}

This is the error that I get:

java.lang.RuntimeException: Unable to start activity ComponentInfo{xxx.xxx/xxx.xxx.MainActivity}: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected STRING but was BEGIN_OBJECT

The reason I want details as string not as a JsonObject because I'm using Realm DB object and persist that to the database. How can I tell Gson I want the details as string.

Your "json" isn't actually JSON - the field names aren't in quotes. It should be `{ "id": 123, "name": "", "details": {} }`. That *may* be all that's wrong. It would help if you'd show a short but complete program demonstrating the problem, mind you... — Jon Skeet, Jul 06 '15 at 20:30
You can take the JSON Object and convert it to JSON String before saving in DB if you are question is with respect to only "details" attribute. — Wand Maker, Jul 06 '15 at 20:32
`"details":{}` not compatible with `String details;` (that's what the error is telling you. It expects a String, but finds an Object, and bam.) — njzk2, Jul 06 '15 at 20:40

kdbanman · Answer 1 · 2015-07-06T20:41:21.273

1

The details value, {}, is an object not a string. It will not be interpreted as a string unless you quote it like this:

{
"id":123,
"name":"",
"details":"{}"
}

GSON is telling you "Expected STRING but was BEGIN_OBJECT". This makes sense, because you're giving it a type signature with a String attribute named details, but your serialization has an attribute named details that contains an empty object.

edited Jul 06 '15 at 20:41

answered Jul 06 '15 at 20:33

kdbanman

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Thanks, my fault. This is just an example, didn't want to share internal details. I'll fix the example. – Jimmy Jul 06 '15 at 20:36
Alright. I'll add details to help with the actual problem then. – kdbanman Jul 06 '15 at 20:38
@Jimmy: when posting a question, post input and code that actually demonstrate the issue. – njzk2 Jul 06 '15 at 20:41
@njzk2 I did, I had a mistake in the example I provided and fixed it. But I understand your comment. – Jimmy Jul 06 '15 at 20:43
@Jimmy, I think he meant the GSON calling code, specifically. Did my answer work for you? – kdbanman Jul 06 '15 at 22:20

score 0 · Accepted Answer · answered Jul 09 '15 at 15:25

0

I didn't find a nice way to solve it but currently I copy the json object and stringify it to variable, remove it from the json element and then call gson fromJson.

answered Jul 09 '15 at 15:25

Jimmy

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Parsing json to a string in Gson

2 Answers2