在Go中通过反射创建结构

Question

I want to define a struct completely dynamically, so that I can get the following struct, but without defining it first?

type Data struct {
   a string
   b int `json:"b"`
}
d := Data{}

Answer 1

An application can create a struct programmatically using reflect.StructOf, but all fields in the struct must be exported.

The question gets the struct as a value, but it's likely that a pointer to the struct is more useful to the application.

Given the above, this answer shows how to do the following without defining the type at compile time:

type Data struct {
   A string `json:"a"`
   B int `json:"b"`
}
var d interface{} = &Data{}

The code is:

t := reflect.StructOf([]reflect.StructField{
    {
        Name: "A",
        Type: reflect.TypeOf(int(0)),
        Tag:  `json:"a"`,
    },
    {
        Name: "B",
        Type: reflect.TypeOf(""),
        Tag:  `json:"B"`,
    },
})
d := reflect.New(t).Interface()

Here's a runnable example that sets some fields: https://play.golang.org/p/uik7Ph8_BRH