遇到将文本解组为结构体时出现问题。

huangapple
go评论121阅读模式
英文:

Trouble unmarshaling text into struct

问题

尝试将一个 JSON 文本解组为自定义的结构体。我的结构体定义似乎是正确的，但 json.Unmarshal 没有返回任何内容。

  1. package main
  3. import (
  4. 	"encoding/json"
  5. 	"fmt"
  6. )
  8. type CmdUnit struct {
  9. 	Command     string
  10. 	Description string
  11. }
  13. type CmdList struct {
  14. 	ListOfCommands []CmdUnit
  15. }
  17. type OneCmdList struct {
  18. 	Area    string
  19. 	CmdList CmdList
  20. }
  22. type AllCommands struct {
  23. 	AllAreas []OneCmdList
  24. }
  26. func main() {
  27. 	jsonTxt := `
  28. 	{
  29.         "Area1": [{
  30.                 "Command": "cmd1",
  31.                 "Desc": "cmd1 desc"
  32.         }, {
  33.                 "Command": "cmd2",
  34.                 "Desc": "cmd2 desc"
  35.         }],
  36.         "Area2": [{
  37.                 "Command": "cmd1",
  38.                 "Desc": "cmd1 desc"
  39.         }]
  41. }
  42. `
  43. 	cmds := AllCommands{}
  44. 	if err := json.Unmarshal([]byte(jsonTxt), &cmds); err != nil {
  45. 		fmt.Println("Failed to unmarshal:", err)
  46. 	} else {
  47. 		fmt.Printf("%+v\n", cmds)
  48. 	}
  49. }
  52. $ go run j.go
  53. {AllAreas:[]}

以上是你要翻译的内容。

英文:

Trying to unmarshal a json text into my own struct. My struct definitions seem correct but json.Unmarshal doesn't return anything.

  1. package main
  3. import (
  4. 	"encoding/json"
  5. 	"fmt"
  6. )
  8. type CmdUnit struct {
  9. 	Command     string
  10. 	Description string
  11. }
  13. type CmdList struct {
  14. 	ListOfCommands []CmdUnit
  15. }
  17. type OneCmdList struct {
  18. 	Area    string
  19. 	CmdList CmdList
  20. }
  22. type AllCommands struct {
  23. 	AllAreas []OneCmdList
  24. }
  26. func main() {
  27. 	jsonTxt := `
  28. 	{
  29.         "Area1": [{
  30.                 "Command": "cmd1",
  31.                 "Desc": "cmd1 desc"
  32.         }, {
  33.                 "Command": "cmd2",
  34.                 "Desc": "cmd2 desc"
  35.         }],
  36.         "Area2": [{
  37.                 "Command": "cmd1",
  38.                 "Desc": "cmd1 desc"
  39.         }]
  41. }
  42. `
  43. 	cmds := AllCommands{}
  44. 	if err := json.Unmarshal([]byte(jsonTxt), &cmds); err != nil {
  45. 		fmt.Println("Failed to unmarshal:", err)
  46. 	} else {
  47. 		fmt.Printf("%+v\n", cmds)
  48. 	}
  49. }
  52. $ go run j.go
  53. {AllAreas:[]}

答案1

得分: 3

你的结构体与你提供的 JSON 有不同的结构。在你的示例中，将结构体编组将导致以下 JSON 结构：

  1. {
  2.   "AllAreas": [
  3.     {
  4.       "Area": "Area1",
  5.       "CmdList": {
  6.         "ListOfCommands": [
  7.           {
  8.             "Command": "cmd1",
  9.             "Description": "cmd1 desc"
  10.           },
  11.           {
  12.             "Command": "cmd2",
  13.             "Description": "cmd2 desc"
  14.           }
  15.         ]
  16.       }
  17.     }
  18.   ]
  19. }

在你的示例中，可以直接将 JSON 反编组为 map[string][]CmdUnit{}，只需将 CmdUnit.Description 更改为 CmdUnit.Desc。

  1. cmds := map[string][]CmdUnit{}
  2. if err := json.Unmarshal(jsonTxt, &cmds); err != nil {
  3.     log.Fatal("Failed to unmarshal:", err)
  4. }
  5. fmt.Printf("%+v\n", cmds)

链接：https://play.golang.org/p/DFLYAfNLES

英文:

Your structs have a different structure from the json you're providing. Marshalling the structs in your example would result in json that looks like:

  1. {
  2.   "AllAreas": [
  3.     {
  4.       "Area": "Area1",
  5.       "CmdList": {
  6.         "ListOfCommands": [
  7.           {
  8.             "Command": "cmd1",
  9.             "Description": "cmd1 desc"
  10.           },
  11.           {
  12.             "Command": "cmd2",
  13.             "Description": "cmd2 desc"
  14.           }
  15.         ]
  16.       }
  17.     }
  18.   ]
  19. }

The json in your example can be unmarshaled directly into a map[string][]CmdUnit{} with the minor change of CmdUnit.Description to CmdUnit.Desc.

  1. cmds := map[string][]CmdUnit{}
  2. if err := json.Unmarshal(jsonTxt, &cmds); err != nil {
  3. 	log.Fatal("Failed to unmarshal:", err)
  4. }
  5. fmt.Printf("%+v\n", cmds)

https://play.golang.org/p/DFLYAfNLES

huangapple
  • 本文由 发表于 2017年2月23日 07:48:00
  • 转载请务必保留本文链接：https://go.coder-hub.com/42404484.html
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