Convert a Map<String, String> to a POJO

I've been looking at Jackson, but is seems I would have to convert the Map to JSON, and then the resulting JSON to the POJO.

Is there a way to convert a Map directly to a POJO?

Solution 1:

Well, you can achieve that with Jackson, too. (and it seems to be more comfortable since you were considering using jackson).

Use ObjectMapper's convertValue method:

final ObjectMapper mapper = new ObjectMapper(); // jackson's objectmapper
final MyPojo pojo = mapper.convertValue(map, MyPojo.class);

No need to convert into JSON string or something else; direct conversion does much faster.

Solution 2:

A solution with Gson:

Gson gson = new Gson();
JsonElement jsonElement = gson.toJsonTree(map);
MyPojo pojo = gson.fromJson(jsonElement, MyPojo.class);

Solution 3:

if you have generic types in your class you should use TypeReference with convertValue().

final ObjectMapper mapper = new ObjectMapper();
final MyPojo<MyGenericType> pojo = mapper.convertValue(map, new TypeReference<MyPojo<MyGenericType>>() {});

Also you can use that to convert a pojo to java.util.Map back.

final ObjectMapper mapper = new ObjectMapper();
final Map<String, Object> map = mapper.convertValue(pojo, new TypeReference<Map<String, Object>>() {});