java - Spring 启动 : Can I post multiple objects as multiple @RequestParams to a REST service?

Question

我使用 Spring Boot 使用单个资源构建了玩具 REST 服务，如下所示:

@RestController
@RequestMapping("/checkout")
public class CheckoutRestController {

    @PostMapping("/book")
    public boolean buyBook(@RequestParam CreditCard creditCard, @RequestParam ShippingAddress shippingAddress) {
        return true;
    }
}

CreditCard 和 ShippingAddress 都是我编写的 POJO(普通旧 Java 对象)。

我已尝试使用此有效负载发布到此端点:

{
    "creditCard" : {
        "nameOnCard":"foo",
        "number":12345678,
        "expiryMonth":12,
        "expiryYear":2018,
        "ccv":100
    },
    "shippingAddress" : {
        "steert":"foor",
        "houseNumber":"1a",
        "city":"bar",
        "state":"bazz",
        "country":"buzz",
        "zipCode":"booz"
    },
}

但是我得到一个错误:

{
    "timestamp": "2018-03-13T11:36:52.745+0000",
    "status": 400,
    "error": "Bad Request",
    "message": "Required CreditCard parameter 'creditCard' is not present",
    "path": "/checkout/book"
}

我知道一个解决方法是将两个 POJO 包装在一个请求包装器中，但我宁愿不这样做，除非我真的必须这样做。

是否可以发布两个@RequestParam 注解的对象？如果是这样，JSON 会是什么样子？

Answer 1

@RequestParam参数是query参数，不是body参数。

这意味着您的方法:

@PostMapping("/book")
public boolean buyBook(@RequestParam CreditCard creditCard, @RequestParam 
    ShippingAddress shippingAddress) {

        return true;
}

需要以下请求:

POST /checkout/book?creditCard=<...>&shippingAddress=<...>

但是，Spring 不知道如何将 String 查询参数转换为 CreditCard 或 ShippingAddress。

您可以通过实现Converter 来解决这个问题，如下所示:

public class StringToCreditCardConverter implements Converter<String, CreditCard> {

    @Override
    public CreditCard convert(String source) {
         <...>
    }
}

但是，我不推荐这样做，因为它不是请求主体的标准，并且会导致很多困惑和可维护性问题。

相反，推荐的方式如下:

@PostMapping("/book")
public boolean buyBook(@RequestBody BookCreationRequest bookCreationRequest) {
        CreditCard creditCard = bookCreationRequest.getCreditCard();
        ShippingAddress shippingAddress = bookCreationRequest.getShippingAddress();
        ...
}

bookCreationRequest 包含 CreditCard 和 ShippingAddress 字段(注意:您可以使用例如 lombok 来减少样板代码):

public class BookCreationRequest {
    private ShippingAddress shippingAddress;
    private CreditCredit creditCard;

    public ShippingAddress  getShippingAddress() {...}
    public CreditCard       getCreditCard() {...}

    public BookCreationRequest(ShippingAddress shippingAddress, CreditCard creditCard) {
        this.creditCard = creditCard;
        this.shippingAddress = shippingAddress;
}

然后期望请求 JSON 如下:

POST /checkout/book
Payload:
{
    "creditCard": {
        ... 
    },
    "shippingAddress": {
        ...
    }
}

注意一个请求中只能有一个@RequestBody参数。