How to Unmarshal a JSON Object into an Array of Structs in Go?

How to Unmarshal JSON to Array of Objects in Go

Question

How can I unmarshal the following JSON into an array of objects in the Go language?

{
    "1001": {"level":10, "monster-id": 1001, "skill-level": 1, "aimer-id": 301},
    "1002": {"level":12, "monster-id": 1002, "skill-level": 1, "aimer-id": 302},
    "1003": {"level":16, "monster-id": 1003, "skill-level": 2, "aimer-id": 303}
}

Solution

The provided JSON requires some modifications to be valid, such as adding commas between key-value pairs in the top-level object:

{
   "1001":{
      "level":10,
      "monster-id":1001,
      "skill-level":1,
      "aimer-id":301
   },
   "1002":{
      "level":12,
      "monster-id":1002,
      "skill-level":1,
      "aimer-id":302
   },
   "1003":{
      "level":16,
      "monster-id":1003,
      "skill-level":2,
      "aimer-id":303
   }
}

To unmarshal this JSON into an array of objects, you can use the following code:

type Monster struct {
    MonsterId  int32 `json:"monster-id"`
    Level      int32 `json:"level"`
    SkillLevel int32 `json:"skill-level"`
    AimerId    int32 `json:"aimer-id"`
}

type MonsterCollection struct {
    Pool map[string]Monster
}

func (mc *MonsterCollection) FromJson(jsonStr string) error {
    var data =&mc.Pool
    b := []byte(jsonStr)
    return json.Unmarshal(b, data)
}

In this code:

• The Monster struct represents the structure of the objects.
• The MonsterCollection struct contains a pool of monsters, each keyed by a string.
• The FromJson method unmarshals the JSON string into the Pool map.

The error return is useful for debugging purposes, allowing you to detect errors such as invalid JSON syntax.

A working example can be found on the Golang Playground: http://play.golang.org/p/4EaasS2VLL.

The above is the detailed content of How to Unmarshal a JSON Object into an Array of Structs in Go?. For more information, please follow other related articles on the PHP Chinese website!