Serialize legacy nested Java Code to Json

1
votes

Looking for some help to serialize a deep nested java objects to Json. The constraint is that I cannot add any annotations or change the current Java code. Looking for a powerful Json library which has configuration options to convert Java to Json without altering the Java Object themselves. Following would be some of the options that might be required

  1. Specify include/exclude fields/methods. Should be able to specify this at nested levels. A is composed of B and B is composed of C. Should have ability to specify include/exclude at C.

  2. Include/Exclude Objects at nested levels.

  3. Rename fields from java properties while converting to Json (at nested level objects too)

  4. Manager circular dependencies.

Was looking at Jackson and Gson for this requirements. While there are tons of options using annotations to specify serialization configs while writing new Java Pojo's, I am looking at options where I need to specify serialization properties without changing the current Java code. Jackson and Gson do seem to have options for these, but not documented in depth. Which library is easier to configure for the above requirements? Any other powerful library other than Jackson/Gson? Any pointers to this will be of great help.

Thanks much for your time.

1
jsonserializationnestedjacksongson

1 Answers

0
votes

As to Jackson, you might consider using so-called mix-in annotations (see f.ex http://www.studytrails.com/java/json/java-jackson-mix-in-annotation.jsp) which allow you to specify mix-ins to use, without adding them directly in the legacy classes. This would let you use annotation-based configuration, but leave actual classes untouched.

But given all of your requirements, it may perhaps be better to just use Tree Model of Jackson or GSON (get JsonNode or such), and manually handle conversions to your liking. You may then be able to convert tree value into POJO; Jackson, for example, has method(s) for doing this (ObjectMapper.treeToValue(), .valueToTree(), .convertValue()) which allow conversions of structurally compatible representations.