Parsing a json object which has many fields

Question

I want to parse json from a server and place it into a class. I use json4s for this. The issue is that a json object contains too many fields, it's about 40-50 of them, some of them have the long names.

I wonder, what will be a sensible way to store all of them, will I have to create 40-50 fields in a class? Remember, some of them will have the long names, as I said earlier.

I use Scala, but a Java's approach might be similar to it, so I added a tag of Java also.

Answer 1

I don't know json4s but in Jersey with Jackson, for example, you can use a Map to hold the Json data or you can use a POJO with all those names.

Sometimes its better to have the names. It makes the code much easier to understand.

Sometimes its better to use a Map. For example, if the field names change from time to time.

If I recall it correctly, using pure Jackson you do something like this:

String jsonString = ....; // This is the string of JSON stuff
JsonFactory factory = new JsonFactory(); 
ObjectMapper mapper = new ObjectMapper(factory);  // A Jackson class
Map<String,Object> data = mapper.readValue(jsonString, HashMap.class); 

You can use a TypeReference to make it a little cleaner as regards the generics. Jackson docs tell more about it. There is also more here: StackOverflow: JSON to Map

Answer 2

There are generally two ways of parsing json to object 1) Parse json to object representation. the other which might suit you as you mention that your object has too many fields is amap/hashtable, or you could just keep it as JObject, an get fields ehrn you need them