如何将 map[string]interface{} 数据转换为结构体（struct）？

huangapple
go评论119阅读模式
英文:

how to convert map[string]interface{} data to struct

问题

我不知道如何提问，所以我将用一个例子来提问。

我有一些数据，如下所示：

  1. {
  2. ..
  3. 	"velocityStatEntries":  {
  5. 	"8753": {
  7. 		"estimated": {"value": 23.0,"text": "23.0"},
  9. 		"completed": {"value": 27.0,"text": "27.0"}
  10. 	},
  12. 	"8673": {
  14. 		"estimated": {"value": 54.5,"text": "54.5"},
  16. 		"completed": {"value": 58.5,"text": "58.5"}
  17. 	},
  18. 	.
  19. 	.
  20. 	.
  22. 	}
  23. ..
  24. }

我想声明一个类型，将映射键值作为它的"KEY"或我指定的任何属性。是否可以在不使用映射迭代的情况下实现？

期望的输出：

  1. {...
  2.    "velocityStatEntries": {
  3.    {
  4. 	 "key": "8753",
  5. 	 "estimated": {"value": 54.5,"text": "54.5"},
  6. 	 "completed": {"value": 58.5,"text": "58.5"}
  7.    },
  8.    {
  9. 	 "key": "8673",
  10. 	 "estimated": {"value": 54.5,"text": "54.5"},
  11. 	 "completed": {"value": 58.5,"text": "58.5"}
  12.    },
  13.   }
  14. ...
  15. }

这是我所做的：

  1. type VelocityStatEntry struct {
  2. 	Key string
  3. 	Estimated struct {
  4. 		Value float64 `json:"value"`
  5. 		Text  string  `json:"text"`
  6. 	} `json:"estimated"`
  7. 	Completed struct {
  8. 		Value float64 `json:"value"`
  9. 		Text  string  `json:"text"`
  10. 	} `json:"completed"`
  11. }
  13. type RapidChartResponse struct {
  14. 	...
  15. 	VelocityStatEntries map[string]VelocityStatEntry `json:"velocityStatEntries"`
  16. 	..
  17. }

但它不起作用。我想将字符串映射键值作为KEY属性。

英文:

I do not know how to ask, so i will ask with an example.

I have some data like that

  1. {
  2. ..
  3. 	"velocityStatEntries":  {
  5. 	"8753":  {
  7. 		"estimated":  {"value":  23.0,"text":  "23.0"},
  9. 		"completed":  {"value":  27.0,"text":  "27.0"}
  10. 	},
  12. 	"8673":  {
  14. 		"estimated":  {"value":  54.5,"text":  "54.5"},
  16. 		"completed":  {"value":  58.5,"text":  "58.5"}
  17. 	},
  18. 	.
  19. 	.
  20. 	.
  22. 	}
  23. ..
  24. }

I want to declare a type that takes map key to its "KEY" or any property that is given by me.
Is it possible without using map iteration?

Expected output:

  1. {...
  2.    "velocityStatEntries": {
  3.    {
  4. 	 "key": "8753",
  5. 	 "estimated":  {"value":  54.5,"text":  "54.5"},
  6. 	 "completed":  {"value":  58.5,"text":  "58.5"}
  7.    },
  8.    {
  9. 	 "key": "8673",
  10. 	 "estimated":  {"value":  54.5,"text":  "54.5"},
  11. 	 "completed":  {"value":  58.5,"text":  "58.5"}
  12.    },
  13.   }
  14. ...
  15. }

This is what i have done

  1. type VelocityStatEntry struct {
  2. 	Key string
  3. 	Estimated struct {
  4. 		Value float64 `json:"value"`
  5. 		Text  string  `json:"text"`
  6. 	} `json:"estimated"`
  7. 	Completed struct {
  8. 		Value float64 `json:"value"`
  9. 		Text  string  `json:"text"`
  10. 	} `json:"completed"`
  11. }
  13. type RapidChartResponse struct {
  14. 	...
  15. 	VelocityStatEntries map[string]VelocityStatEntry `json:"velocityStatEntries"`
  16. 	..
  17. }

But it is not working. I want to take that string map key to KEY property.

答案1

得分: 3

如果数据源是JSON格式的，那么你应该跳过map[string]interface{}，而是使用你所需的自定义解组器（custom unmarshaler）来实现你想要的功能。可以考虑使用map[string]json.RawMessage。但是，如果可能的话，尽量避免使用map[string]interface{}转换为结构体，因为这样做会很麻烦。

例如：

  1. type VelocityStatEntryList []*VelocityStatEntry
  3. func (ls *VelocityStatEntryList) UnmarshalJSON(data []byte) error {
  4. 	var m map[string]json.RawMessage
  5. 	if err := json.Unmarshal(data, &m); err != nil {
  6. 		return err
  7. 	}
  8. 	for k, v := range m {
  9. 		e := &VelocityStatEntry{Key: k}
  10. 		if err := json.Unmarshal([]byte(v), e); err != nil {
  11. 			return err
  12. 		}
  13. 		*ls = append(*ls, e)
  14. 	}
  15. 	return nil
  16. }

https://go.dev/play/p/VcaW_BWXRVr

英文:

If the data originates from JSON then you should skip the map[string]interface{} and instead use a custom unmarshaler implemented by your desired struct that does what you want. Perhaps by utilizing a map[string]json.RawMessage. But map[string]interface{} to struct conversion is a pain, avoid it if possible.

For example:

  1. type VelocityStatEntryList []*VelocityStatEntry
  3. func (ls *VelocityStatEntryList) UnmarshalJSON(data []byte) error {
  4. 	var m map[string]json.RawMessage
  5. 	if err := json.Unmarshal(data, &m); err != nil {
  6. 		return err
  7. 	}
  8. 	for k, v := range m {
  9. 		e := &VelocityStatEntry{Key: k}
  10. 		if err := json.Unmarshal([]byte(v), e); err != nil {
  11. 			return err
  12. 		}
  13. 		*ls = append(*ls, e)
  14. 	}
  15. 	return nil
  16. }

https://go.dev/play/p/VcaW_BWXRVr

huangapple
  • 本文由 发表于 2022年1月7日 21:29:23
  • 转载请务必保留本文链接：https://go.coder-hub.com/70621975.html
  • go
  • go-map
  • json
  • struct
  • types
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定