Golang convert interface {} to struct

Question

我想在下面的代码中改进getCustomerFromDTO方法，我需要从接口{}创建一个结构，并且当前我需要将该接口编组为byte []，然后解组该数组到我的结构 - 必须有更好的方法。

我的用例是，我通过rabbitmq发送结构并发送它们，我使用这个通用的DTO包装器，它具有关于它们的其他特定于域的数据。 当我收到来自rabbit mq的DTO时，消息下面的一层被解组到我的DTO，然后我需要从该DTO获取我的结构。

type Customer struct { 
    Name string `json:"name"` 
} 

type UniversalDTO struct { 
    Data interface{} `json:"data"` 
    // more fields with important meta-data about the message... 
} 

func main() { 
    // create a customer, add it to DTO object and marshal it 
    customer := Customer{Name: "Ben"} 
    dtoToSend := UniversalDTO{customer} 
    byteData, _ := json.Marshal(dtoToSend) 

    // unmarshal it (usually after receiving bytes from somewhere) 
    receivedDTO := UniversalDTO{} 
    json.Unmarshal(byteData, &receivedDTO) 

    //Attempt to unmarshall our customer 
    receivedCustomer := getCustomerFromDTO(receivedDTO.Data) 
    fmt.Println(receivedCustomer) 
} 

func getCustomerFromDTO(data interface{}) Customer { 
    customer := Customer{} 
    bodyBytes, _ := json.Marshal(data) 
    json.Unmarshal(bodyBytes, &customer) 
    return customer 
} 

Answer 1

解编DTO之前，请将Data字段设置为您所期望的类型。

type Customer struct { 
    Name string `json:"name"` 
} 

type UniversalDTO struct { 
    Data interface{} `json:"data"` 
    // more fields with important meta-data about the message... 
} 

func main() { 
    // create a customer, add it to DTO object and marshal it 
    customer := Customer{Name: "Ben"} 
    dtoToSend := UniversalDTO{customer} 
    byteData, _ := json.Marshal(dtoToSend) 

    // unmarshal it (usually after receiving bytes from somewhere) 
    receivedCustomer := &Customer{} 
    receivedDTO := UniversalDTO{Data: receivedCustomer} 
    json.Unmarshal(byteData, &receivedDTO) 

    //done 
    fmt.Println(receivedCustomer) 
} 

如果你没有初始化的DTO的Data领域的能力，这是取消封送之前，你可以在拆封后使用类型断言。包装encoding/json unamrshals interface{}类型值转换为map[string]interface{}，让您的代码会是这个样子：

type Customer struct { 
    Name string `json:"name"` 
} 

type UniversalDTO struct { 
    Data interface{} `json:"data"` 
    // more fields with important meta-data about the message... 
} 

func main() { 
    // create a customer, add it to DTO object and marshal it 
    customer := Customer{Name: "Ben"} 
    dtoToSend := UniversalDTO{customer} 
    byteData, _ := json.Marshal(dtoToSend) 

    // unmarshal it (usually after receiving bytes from somewhere) 
    receivedDTO := UniversalDTO{} 
    json.Unmarshal(byteData, &receivedDTO) 

    //Attempt to unmarshall our customer 
    receivedCustomer := getCustomerFromDTO(receivedDTO.Data) 
    fmt.Println(receivedCustomer) 
} 

func getCustomerFromDTO(data interface{}) Customer { 
    m := data.(map[string]interface{}) 
    customer := Customer{} 
    if name, ok := m["name"].(string); ok { 
     customer.Name = name 
    } 
    return customer 
}