反射实现JSON序列化与结构体动态解析案例

val := reflect.ValueOf(user)

typ := reflect.TypeOf(user)

for i := 0; i < val.NumField(); i++ {

  field := val.Field(i)

  fieldType := typ.Field(i)

  jsonTag := fieldType.Tag.Get("json")

  if jsonTag == "" || jsonTag == "-" {

    continue

  }

  tagName := jsonTag

  if idx := strings.Split(jsonTag, ","); len(idx) > 0 {

    tagName = idx[0]

  }

  fmt.Printf("%s: %v\n", tagName, field.Interface())

}

result := make(map[string]interface{})

for i := 0; i < val.NumField(); i++ {

  field := val.Field(i)

  fieldType := typ.Field(i)

  tag := fieldType.Tag.Get("json")

  if tag == "" || tag == "-" {

    continue

  }

  parts := strings.Split(tag, ",")

  key := parts[0]

  omitEmpty := false

  for _, opt := range parts[1:] {

    if opt == "omitempty" {

      omitEmpty = true

    }

  }

  if omitEmpty && field.IsZero() {

    continue

  }

  result[key] = field.Interface()

}

if field.Kind() == reflect.Ptr && !field.IsNil() {

  field = field.Elem()

}

if field.Kind() == reflect.Struct {

  // 递归处理子结构体

  result[key] = structToMap(field)

} else {

  result[key] = field.Interface()

}