将具有json-format-string的对象序列化为json

Question

I have an object like:

public class Foo{
  public String f1="[{\"jsonField\":\"something\"},{\"jsonField\":\"something\"}]";
}

Gson would serialize it to:

{"f1":"[{\"jsonField\":\"something\"},{\"jsonField\":\"something\"}]"}

The f1 field was serialized to a string. Apparently, the field is a well formed json-format string. How can I do to serialized the field to an jso array, like below:

{"f1":[{"jsonField":"something"},{"jsonField":"something"}]}

PS. For performance consideration, I can't deserialize then serialize the field.

Answer 1

Gson is serializing your string field to a string. That's normal. If your field, however, was a List<String> , Gson would give you:

{"f1":["jsonField:something","jsonField:something"]}

And if it was a List where something has a field called jsonField you'd get what you actually want.

This is the implicit way that Gson serializes your objects. If you don't like it, you need to implement your own TypeAdapter and register it with Gson at the builder.

GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(MyObject.class, new SomethingGsonAdapter());
Gson gson = builder.create()

And you need to define:

public class SomethingGsonAdapter implements JsonDeserializer<DataItem>, JsonSerializer<DataItem>;