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  1. package main
  2.  
  3. import (
  4. 	"encoding/json"
  5. 	"fmt"
  6. 	"log"
  7. 	"reflect"
  8. )
  9.  
  10. type Person struct {
  11. 	Name string `json:"name"`
  12. 	Age  int    `json:"age"`
  13. 	City string `json:"city"`
  14. }
  15.  
  16. func mapDataToStruct(data map[string]interface{}, target interface{}) {
  17. 	v := reflect.ValueOf(target).Elem()
  18.  
  19. 	for key, value := range data {
  20. 		field := v.FieldByName(key)
  21. 		if !field.IsValid() {
  22. 			log.Printf("Invalid field name: %s\n", key)
  23. 			continue
  24. 		}
  25. 		if !field.CanSet() {
  26. 			log.Printf("Cannot set field: %s\n", key)
  27. 			continue
  28. 		}
  29.  
  30. 		// Handle type conversion
  31. 		switch field.Kind() {
  32. 		case reflect.String:
  33. 			if strVal, ok := value.(string); ok {
  34. 				field.SetString(strVal)
  35. 			} else {
  36. 				log.Printf("Field %s expects a string\n", key)
  37. 			}
  38. 		case reflect.Int:
  39. 			if floatVal, ok := value.(float64); ok {
  40. 				field.SetInt(int64(floatVal)) // Convert float64 to int64
  41. 			} else if intVal, ok := value.(int); ok {
  42. 				field.SetInt(int64(intVal))
  43. 			} else {
  44. 				log.Printf("Field %s expects an int\n", key)
  45. 			}
  46. 		default:
  47. 			log.Printf("Unsupported field type for %s\n", key)
  48. 		}
  49. 	}
  50. }
  51.  
  52. func main() {
  53. 	jsonData := `{"name": "John Doe", "age": 30, "city": "New York"}`
  54.  
  55. 	var person Person
  56.  
  57. 	// Parse JSON into a map
  58. 	data := make(map[string]interface{})
  59. 	if err := json.Unmarshal([]byte(jsonData), &data); err != nil {
  60. 		log.Fatalf("Error parsing JSON: %v", err)
  61. 	}
  62.  
  63. 	// Map the data to the struct using reflection
  64. 	mapDataToStruct(data, &person)
  65.  
  66. 	// Print the resulting struct
  67. 	fmt.Println("Mapped Person:")
  68. 	fmt.Printf("%+v\n", person)
  69. }
  70.  
  71.  
Success #stdin #stdout #stderr 0.01s 5284KB
comments (?)
stdin
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Standard input is empty
stdout
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Mapped Person:
{Name: Age:0 City:}
stderr
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2024/12/17 06:19:52 Invalid field name: name
2024/12/17 06:19:52 Invalid field name: age
2024/12/17 06:19:52 Invalid field name: city
https://ideone.com/61lJXP
422792_turn1_modelB_fixed
language:
Go (go 1.12.1)
created:
5 days ago
visibility:
public

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