SpringBoot：提供缺少某些字段的 JSON 请求

Question

I'm building a POJO class to match some requests coming my way in a REST API implemented on SpringBoot. Some of the data has to be given to me, otherwise I am not willing to even serve the request. To make sure the client gives me at least what I absolutely need, I have used Lombok's @NonNull :

@Data
public class ProductRequestBody implements Serializable
{
    private String name;
    private String category;
    private String description;
    private String abbreviation;
    private String labelColor;
    private Double cost;

    public ProductRequestBody()
    {
    }

    @JsonCreator
    public ProductRequestBody(@NonNull @JsonProperty("name") String name,
                              @NonNull @JsonProperty("category") String category,
                              @JsonProperty("description") String description,
                              @NonNull @JsonProperty("cost") Double cost)
    {
        this.name = name;
        this.category = category;
        this.description = description;
        this.cost = cost;
    }
}

(I completely understand that handling monetary quantities as Double s is a no-no; this is just an example.

Processing this from my controller is as easy as a listener on the /products endpoint like so:

@PostMapping(value = "/products")
public Product postProduct(@RequestBody ProductRequestBody newProduct)
{
   // ... 
   // Serve the request appropriately
   // ... 
}

Now, if I receive a POST request with a null field that has not been marked as @NonNull , like the following, I can serve it without issue:

{
        "name": "Some Product Name",
        "category": "Some Product Category", 
        "cost" : 10.0,
        "description": null
}

My goal, however, is to be able to handle JSON requests that simply don't even have the fields they don't care about. That is, I want to be able to serve the following as well, and I currently can't:

{
        "name": "Some Product Name",
        "category": "Some Product Category", 
        "cost" : 10.0,
        // No "description" field in this payload
}

How could I go about doing this? The less code, the better, as always.

Answer 1

If you use spring-boot and lombok you can simplify your class to be like this:

@Data
public class ProductRequestBody implements Serializable {

    @NonNull
    private String name;

    @NonNull
    private String category;

    @NonNull
    private Double cost;

    private String description;
    private String abbreviation;
    private String labelColor;
}

it will return 400 if name, category or cost will be not provided and 200 otherwise.

Answer 2

Spring handles serializing and deserializing json without any issue. You should let spring handle it.
You can try the following.

@Data
public class ProductRequestBody implements Serializable {
    @NonNull
    private String name;
    @NonNull
    private String category;
    private String description;
    private String abbreviation;
    private String labelColor;
    @NonNull
    private Double cost;
}

If you really want to follow the pattern of creating a constructor, then you should create a constructor with only the @NonNull fields and create getter of others ( lombok handles that for you). If you want to add @JsonProperty then you need to create separate getter.

@Data                                                                                
public class ProductRequestBody implements Serializable                              
{                                                                                    
    private String name;                                                             
    private String category;                                                         
    private String description;                                                      
    private String abbreviation;                                                     
    private String labelColor;                                                       
    private Double cost;                                                             
                                                                                     
    public ProductRequestBody()                                                      
    {                                                                                
    }                                                                                
                                                                                     
    @JsonCreator                                                                     
    public ProductRequestBody(@NonNull @JsonProperty("name") String name,            
                              @NonNull @JsonProperty("category") String category,    
                              @NonNull @JsonProperty("cost") Double cost)            
    {                                                                                
        this.name = name;                                                            
        this.category = category;                                                    
        this.cost = cost;                                                            
    }                                                                                
                                                                                     
    @JsonProperty("description")                                                     
    public String getDescription() {                                                 
        return description;                                                          
    }                                                                                
}