How to convert the following json string to java object?

Question

I want to convert the following JSON string to a java object:

String jsonString = "{   "libraryname": "My Library",   "mymusic": [     {       "Artist Name": "Aaron",       "Song Name": "Beautiful"     },     {       "Artist Name": "Britney",       "Song Name": "Oops I did It Again"     },     {       "Artist Name": "Britney",       "Song Name": "Stronger"     }   ] }" 

My goal is to access it easily something like:

(e.g. MyJsonObject myobj = new MyJsonObject(jsonString) myobj.mymusic[0].id would give me the ID, myobj.libraryname gives me "My Library"). 

I've heard of Jackson, but I am unsure how to use it to fit the json string I have since its not just key value pairs due to the "mymusic" list involved. How can I accomplish this with Jackson or is there some easier way I can accomplish this if Jackson is not the best for this?

Answer 1

No need to go with GSON for this; Jackson can do either plain Maps/Lists:

ObjectMapper mapper = new ObjectMapper(); Map<String,Object> map = mapper.readValue(json, Map.class); 

or more convenient JSON Tree:

JsonNode rootNode = mapper.readTree(json); 

By the way, there is no reason why you could not actually create Java classes and do it (IMO) more conveniently:

public class Library {   @JsonProperty("libraryname")   public String name;    @JsonProperty("mymusic")   public List<Song> songs; } public class Song {   @JsonProperty("Artist Name") public String artistName;   @JsonProperty("Song Name") public String songName; }  Library lib = mapper.readValue(jsonString, Library.class); 

Answer 2

Check out Google's Gson: http://code.google.com/p/google-gson/

From their website:

Gson gson = new Gson(); // Or use new GsonBuilder().create(); MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2 

You would just need to make a MyType class (renamed, of course) with all the fields in the json string. It might get a little more complicated when you're doing the arrays, if you prefer to do all of the parsing manually (also pretty easy) check out http://www.json.org/ and download the Java source for the Json parser objects.