Go：是否可以编组循环的 json

Question

I'm coding Go to create a Circular Singly Linked List: https://www.geeksforgeeks.org/circular-singly-linked-list-insertion/

Here is my code:

type Node struct {
    Name string `json:"name"`
    Next *Node  `json:"next"`
}

func main() {
    n1 := Node{Name: "111", Next: nil}
    n2 := Node{Name: "222", Next: &n1}
    n3 := Node{Name: "333", Next: &n2}
    n1.Next = &n3
}

However, when I try to marshal, I get an error: json: unsupported value: encountered a cycle via *main.Node

res, err := json.Marshal(n1)
if err != nil {
    fmt.Println(err)
} else {
    fmt.Println(res)
}

Well, I understand why I get this error. So I want to know if there is some method to allow me to convert the struct of Node to JSON.

Answer 1

From the documentation of encoding/json.Marshal

JSON cannot represent cyclic data structures and Marshal does not handle them. Passing cyclic structures to Marshal will result in an error.

The main part is "JSON cannot represent cyclic data structures" so the answer is a clear No: It is not possible to have JSON which represents your value. You must redesign.