Go json.Unmarshal返回假结构

Question

Golang newbie here

I'm trying to parse from a .json file (in the same directory as the Go code) into a struct holding other structs and the closest I can get to success is a struct containing boolean false, which sounds broken to me.

Here's what I have in my Go code so far

package main

import (
    "encoding/json"
    "fmt"

    "io/ioutil"
)

type App struct {
    Name string `json:"app:name"`
}

type Database struct {
    Type     string `json:"database:type"`
    Name     string `json:"database:name"`
    User     string `json:"database:user"`
    Password string `json:"database:password"`
}

type Environment struct {
    Mode  string `json:"environment:mode"`
    Debug bool   `json:"environment:debug"`
}

type Config struct {
    Environment Environment
    App         App
    Database    Database
}

func main() {
    config, err := ioutil.ReadFile("config.json")
    if err != nil {
        fmt.Errorf("Error reading config file: %s", err)
    }

    var appSettings Config
    json.Unmarshal(config, &appSettings)

    fmt.Print(appSettings)
}

and here's the contents of my .json file

{
  "App": {
    "Name": "My_Project"
  },
  "Database": {
    "Type": "postgres",
    "Name": "my_project_db_name",
    "User": "my_project_db_user",
    "Password": "secret"
  },
  "Environment": {
    "Mode": "development",
    "Debug": true
  }
}

EDIT: Here's the result of the print at the end of main()

{{ false} {} { }}

I have already validated the json content which is fine. The struct names and properties are being exported. Can you see what I'm doing wrong?

Answer 1

Can you try by changing like this:

type App struct {
    Name string `json:"name"`
}

type Database struct {
    Type     string `json:"type"`
    Name     string `json:"name"`
    User     string `json:"user"`
    Password string `json:"password"`
}

type Environment struct {
    Mode  string `json:"mode"`
    Debug bool   `json:"debug"`
}

Here is the output:

{{development true} {My_Project} {postgres my_project_db_name my_project_db_user secret}}

Here is a little docs for handy reference:

// Field is ignored by this package.
Field int `json:"-"`

// Field appears in JSON as key "myName".
Field int `json:"myName"`

// Field appears in JSON as key "myName" and
// the field is omitted from the object if its value is empty,
// as defined above.
Field int `json:"myName,omitempty"`

// Field appears in JSON as key "Field" (the default), but
// the field is skipped if empty.
// Note the leading comma.
Field int `json:",omitempty"`