Read JsonNode into a pre-existed POJO

Question

currently I'm doing this to convert JsonNode to a POJO:

try {
    MyClass obj = mapper.treeToValue(jsonData, MyClass.class)));
    /* consume obj */
} catch (JsonProcessingException ex) {
    return false;
}

But sometimes I don't want to get a new instance of MyClass. I have have populated it before and now I just want to set new values for some fields and keep old values for unchanged fields. What I want is something like this: mapper.readJsonNodeToPOJO(jsonData, obj))); Is it possible to do this?

Why don't you add an inner object inside MyClass that maps the node? — inigoD, Aug 04 '14 at 06:36
@inigoD I don't understand your comment, can you explain a bit more? — Majid Azimi, Aug 04 '14 at 06:38

score 1 · Accepted Answer · edited May 23 '17 at 12:11

1

Use the ObjectMapper.readerForUpdating method. Similar question has been asked here and here

edited May 23 '17 at 12:11

Community

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answered Aug 04 '14 at 07:53

Alexey Gavrilov

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inigoD · Answer 2 · 2014-08-04T06:52:25.887

0

You can do an inner custom object:

public class MyClass{
  MyNode node:
  ....
}

public class MyNode{
   .....
}

This way you can do:

MyClass obj = mapper.treeToValue(jsonData, MyClass.class)));

and:

obj.setNode(mapper.treeToValue(jsonSubData, MyNode.class))

edited Aug 04 '14 at 06:52

answered Aug 04 '14 at 06:44

inigoD

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Read JsonNode into a pre-existed POJO

2 Answers2