杰克逊如何使用自定义获取器/设置器序列化地图？

Question

I have a bean in jackson which uses the @JSonAnySetter method to store all unknown parameters in a map.

@JSonAnySetter
handleUnkowns(String k, Object v) 
{
   myMap.put(k,v); 
}

I use this as the "Base bean" for all my data types, so that if data is missing, the unknown parameters are populated and data is not lost.... rather than jackson crashing.

However, I want the serialized form of these unknowns to NOT be nested - that is - I want serialized parameters to be at the top level of the object, when the object is serialized. Additionally, I want the custom fields to also be serialized :

//I want this map to be serialized/deserialized : {"collarWidth":10 "name":"fido"}
class Dog extens JSonBean 
{
     int collarWidth=0;
     getCollarWidth(){return collarWidth;}
     setCollarWidth(int x){collarWidth=x;}
}

Note that in the above case - since I extend from a Map, Jackson's custom Map serialization will take place, and the unknownParameters will be a "field" in my json.

Thus the expected JSON serialization would be
{"collarWidth":10 "unknownParameters":{"name":"fido"}}

rather than

{"collarWidth":10 "name":"fido"}

So - what is the simplest way to "merge" the unknown parameters with the known ones, so that the java bean serializer retains the same nesting as the input string ?

The obvious solution is to merge the parameters from the "myMap" object with the serialized map , but that seems like overkill, and i assume that this problem might have a more elegant solution.

Answer 1

Have you checked out @JsonAnyGetter annotation? Map that method returns will be unwrapped, to make it work with @JsonAnySetter . This blog entry explains usage.