CODEWITHSUNDEEP
javajsongson
MichelReap
MichelReap

Reputation: 5770

Applying default serializer to properties in Custom Serializer (GSON)

I am writing a custom serializer for my domain objects in GSON, so it only serializes certain objects: 

 @Override
    public JsonElement serialize(BaseModel src, Type typeOfSrc, JsonSerializationContext context) {

        JsonObject obj = new JsonObject();


        Class objClass= src.getClass();

        try {
            for(PropertyDescriptor propertyDescriptor : 
                Introspector.getBeanInfo(objClass, Object.class).getPropertyDescriptors()){

                                    if(BaseModel.class.isAssignableFrom(propertyDescriptor.getPropertyType()))
                {
                    //src.getId()
                }
                else if(Collection.class.isAssignableFrom(propertyDescriptor.getPropertyType()))
                {
                    //whatever
                }
                else {
                    String value = (propertyDescriptor.getReadMethod().invoke(src)) != null?propertyDescriptor.getReadMethod().invoke(src).toString():"";
                    obj.addProperty(propertyDescriptor.getName(), value);
                }
            }
        } catch (IntrospectionException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


        return obj;
    }

The thing is I also want to serialize HashMaps, but this way I get values like these:

{"key"=com.myproject.MyClass@28df0c98}

While I want the default serializing behavior Gson applies to HashMaps. How can I tell GSON to act "normally" with serializing certain objects?

Upvotes: 3

Views: 2050

Answers (2)

JayC667
JayC667

Reputation: 2576

What you COULD do is to instantiate another GsonBuilder and use that. You can even append additional info, like I do in the last line of code (33% chance of being able to edit the list)

final GsonBuilder gb = new GsonBuilder();
JsonObject serializedObject = (JsonObject) gb.create().getAdapter(HashMap.class).toJsonTree(yourMap);
serializedObject.addProperty("canEdit", Math.random < 0.33); // append additional info

You can then include that serializedObject into your properties, or return it.

Upvotes: 0

MikO
MikO

Reputation: 18741

WARNING: Answer out of date.
Although this answer was initially accepted and upvoted, later on it's also had downvotes and comments saying it's wrong, so I guess it's out of date.

I'm pretty sure you can use the JsonSerializationContext context object that you have as a parameter of the serialize method.

Actually, according to Gson API documentation, this object has a method serialize that:

Invokes default serialization on the specified object.

So I guess you just need to do something like this in the point where you want to serialize your HashMap normally:

context.serialize(yourMap);

Upvotes: 3

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