在Go中将组合对象转换为json

Question

I am new to Go and am unsure about how to approach this problem. In OOP terms, I have a base class of Animal and two subclasses of Cat and Dog. I want to specify a ToJson method for Animal which will work for all animals.

My problem is that when I call dog.ToJson() I only get the Dog properties of dog and none of the Animal properties.

How can I make ToJson work as expected (ie with recursion)?

edit: Changed code to reflect suggestions in answer by lbonn, which I could not get to work how I want it to. edit2: consistency in question following code change

package main

import (
    "encoding/json"
    "fmt"
)

type Animal struct {
    Name string
}

type Cat struct {
    CatProperty int64
    Animal
}

type Dog struct {
    DogProperty int64
    Animal
}

func ToJson(i interface{}) []byte {
        data,err := json.Marshal(i)
    if err != nil {
        panic("???")
    }
    return data
}

func main() {
    dog := Dog{}
    dog.Name = "rex"
    dog.DogProperty = 2
    fmt.Println(string(ToJson(dog)))
    // Prints {"DogProperty":2}
    // I want it to print {"Name":"rex","DogProperty":2}
}

Answer 1

Json encoding of anonymous fields was dropped from go 1. Hopefully it will be back in go 1.1. See https://groups.google.com/forum/?fromgroups=#!topic/golang-nuts/jYMHbEv44r4 for more details.

So the best you can get with the standard library right now (with go 1) is http://play.golang.org/p/LncNFeN8ys

You can always use skelterjohn's patch https://github.com/skelterjohn/json/ to support anonymous fields till go 1.1 is released.

Or use tip, installing from source that has this issue fixed. see https://codereview.appspot.com/6460044