通过反射机制，找到相应的Left或者Right广告
type SearchAdsObj struct {
Left PositionAdsObj `json:"left"`
Right PositionAdsObj `json:"right"`
}
func getFieldByName(obj SearchAdsObj, fieldName string) (interface{}, error) {
fmt.Printf("getFieldByName: %s \n", fieldName)
val := reflect.ValueOf(obj)
// fmt.Printf("getFieldByName val %v \n", val)
if val.Kind() != reflect.Struct {
fmt.Printf("getFieldByName input is not a struct")
return nil, fmt.Errorf("getFieldByName input is not a struct")
}
field := val.FieldByName(fieldName)
if !field.IsValid() {
fmt.Printf("getFieldByName field %s not found in the struct", fieldName)
return nil, fmt.Errorf("getFieldByName field %s not found in the struct", fieldName)
}
var inter interface{} = field
if myStruct, ok := inter.(PositionAdsObj); ok {
// 如果转换成功，myStruct现在包含MyStruct类型的值
return myStruct, nil
} else {
// 如果转换失败，说明myInterface不包含MyStruct类型的值
fmt.Println("Conversion failed, myInterface does not contain a PositionAdsObj")
return nil, fmt.Errorf("Conversion failed, myInterface does not contain a PositionAdsObj")
}
}
注意 getFieldByName 传入的是SearchAdsObj具体类型的实体，而不能是：obj interface{}
func getFieldByName(obj interface{}, fieldName string) (interface{}, error) {
因为反射访问结构体内部字段时候，需要操作的对象是一个实际类型的结构体