Golang的Unmarshal Json无法解析所有子结构。

huangapple
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英文:

Golang Unmarshal Json is not parsing all the child structure

问题

我有一个父结构体和两个子结构体ResponseA和ResponseB。我为ParentA结构体编写了"UnmarshalJson"函数。但是ParentB结构体和字符串字段没有解析。我该如何编写自定义的Unmarshal函数，只解析指定的结构体？

  1. type ResponseA struct {
  2.     PageA    int      `json:"pageA"`
  3.     EntriesA []string `json:"entriesA"`
  4. }
  6. type ResponseB struct {
  7.     PageB    int      `json:"pageB"`
  8.     EntriesB []string `json:"entriesB"`
  9. }
  11. type ResponseParent struct {
  12.     ResponseA
  13.     ResponseB
  14.     PageC int `json:"pageC"`
  15. }
  17. func (r *ResponseA) UnmarshalJSON(data []byte) error {
  18.     // 解析ResponseA结构体的逻辑	    
  19. }
  21. func main() {
  22.     jsonStr := `{"pageA": 1, "entriesA": ["classA"], "pageB": 2, "entriesB": ["classC","classD"], "pageC":3}`
  23.     // str := `{"page": 1, "entries": ["classA", "classB"]}`
  25.     var res *ResponseParent
  26.     json.Unmarshal([]byte(jsonStr), &res)
  27.     entriesA := res.EntriesA
  28.     pageA := res.PageA
  29.     entriesB := res.EntriesB
  30.     pageB := res.PageB
  31.     pageC := res.PageC
  33.     fmt.Println("========Response A==========")
  34.     fmt.Println("PageA:", pageA)
  35.     fmt.Println("EntriesA:", entriesA)
  36.     fmt.Println("========Response B==========")
  37.     fmt.Println("PageB:", pageB)
  38.     fmt.Println("EntriesB:", entriesB)
  39.     fmt.Println("PageC:", pageC)
  40. }
  42. 输出结果：
  44. ========Response A==========
  45. PageA: 1
  46. EntriesA: [classA]
  47. ========Response B==========
  48. PageB: 0
  49. EntriesB: []
  50. PageC: 0

你可以在UnmarshalJSON函数中编写解析ResponseA结构体的逻辑，然后在main函数中使用json.Unmarshal解析整个JSON字符串。这样，只有ResponseA结构体会被解析，而ResponseB结构体和其他字段将保持为默认值。

英文:

I have one parent structure and two child structures ResponseA and ResponseB. I wrote "UnmarshalJson" function for ParentA structure. The parentB structure and string field are not parsing.
How can I write the custom Unmarshal which only parse the specified structure/

  1. type ResponseA struct {
  2.     PageA    int      `json:"pageA"`
  3.     EntriesA []string `json:"entriesA"`
  4. }
  6. type ResponseB struct {
  7.     PageB    int      `json:"pageB"`
  8.     EntriesB []string `json:"entriesB"`
  9. }
  11. type ResponseParent struct {
  12.     ResponseA
  13.     ResponseB
  14.     PageC int `json:"pageC"`
  15. }
  17. func (r *ResponseA) UnmarshalJSON(data []byte) error {
  18. // UnMarshal ResponseA structure	    
  19. }
  21. func main() {
  23.     jsonStr := `{"pageA": 1, "entriesA": ["classA"], "pageB": 2, "entriesB": 
  24.     ["classC","classD"], "pageC":3}`
  25.  	// str := `{"page": 1, "entries": ["classA", "classB"]}`
  27.     var res *ResponseParent
  28.     json.Unmarshal([]byte(jsonStr), &res)
  29.     entriesA := res.EntriesA
  30.     pageA := res.PageA
  31.     entriesB := res.EntriesB
  32.     pageB := res.PageB
  33.     pageC := res.PageC
  35.     fmt.Println("========Response A==========a")
  36.     fmt.Println("PageA: %v", pageA)
  37.     fmt.Println("EntriesA: %v", entriesA)
  38.     fmt.Println("========Response B==========a")
  39.     fmt.Println("PageB: %v", pageB)
  40.     fmt.Println("EntriesB: %v", entriesB)
  41.     fmt.Println("PageC: %v", pageC)
  42. }
  44. OutPut:
  46. ========Response A==========a
  47. PageA: %v 1
  48. EntriesA: %v [classA]
  49. ========Response B==========a
  50. PageB: %v 0
  51. EntriesB: %v []
  52. PageC: %v 0

答案1

得分: 3

我测试了一下，我认为这是一个结构性问题，我不知道你是否可以更改你的 JSON 结构，但如果可以的话，你可以尝试只使用两个结构体来实现一个可扩展的结构。

  1. type Response struct {
  2.     Page    int      `json:"page"`
  3.     Entries []string `json:"entries"`
  4. }
  6. type GlobalResponse struct {
  7.     ResponseA Response `json:"pageA"`
  8.     ResponseB Response `json:"pageB"`
  9.     ResponseC Response `json:"pageC"`
  10. }

然后可以这样访问它：

  1. var res *GlobalResponse
  2. json.Unmarshal([]byte(jsonStr), &res)
  3. entriesA := res.ResponseA.Entries
  4. pageA := res.ResponseA.Page
  5. // 对于每个页面都是如此...

最后，JSON 必须更改为以下结构：

  1. {
  2.     "pageA":{
  3.         "page":1,
  4.         "entries":[
  5.             "classA"
  6.         ]
  7.     },
  8.     "pageB":{
  9.         "page":2,
  10.         "entries":[
  11.             "classC",
  12.             "classD"
  13.         ]
  14.     },
  15.     "pageC":{
  16.         "page":3
  17.     }
  18. }

希望对你有所帮助。

英文:

I tested it and I think it's a structural issue, I don't know if you can change your json structure, but if yes you can try to use only 2 structs, to have an evolutive structure

  1. type Response struct {
  2. Page    int      `json:"page"`
  3. Entries []string `json:"entries"`}
  4. }
  6. type GlobalResponse struct {
  7. 	ResponseA Response `json:"pageA"`
  8. 	ResponseB Response `json:"pageB"`
  9. 	ResponseC Response `json:"pageC"`
  10. }

Then acces it this way :

  1. var res *GlobalResponse
  2. json.Unmarshal([]byte(jsonStr), &res)
  3. entriesA := res.ResponseA.Entries
  4. pageA := res.ResponseA.Page
  5. // Etc for each page...

Finally, the json must be changed to that structure

  1. {
  2.     "pageA":{
  3.         "page":1,
  4.         "entries":[
  5.             "classA"
  6.         ]
  7.     },
  8.     "pageB":{
  9.         "page":2,
  10.         "entries":[
  11.             "classC",
  12.         "classD"
  13.         ]
  14.     },
  15.     "pageC":{
  16.         "page":3
  17.     }
  18. }

Hope it helped

huangapple
  • 本文由 发表于 2023年4月6日 16:33:37
  • 转载请务必保留本文链接：https://go.coder-hub.com/75947403.html
  • go
  • unmarshalling
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