如何使用 Spring 验证对大对象的 PATCH 请求

Question

I can't seem to find a lot of information about this. I've read that PUT requests should be used for replacing an entire resource with an updated resource, and that PATCH requests should be used to update only the fields you want to change. But let's say I have a very large object with lots of nested fields and objects, and I want to update only specific fields in one of its nested objects rather than having to resubmit the entire thing (because it's just too large). I would have to create a PATCH endpoint. How would I go about validating such an endpoint in a Spring REST API? I can't get my head around how the endpoint would know which fields or nested fields it has received and how to validate them, and have it work for any possible field I could give it.

Answer 1

When a request comes into spring, it will cast it to an object for example.

 @PatchMapping("/customer/1")
 public void updateCustomer(@RequestBody CustomerPatch updateRequest) {
 }

Here we are casting the customer patch request to a CustomerPatch object.

With this, we can validate the object just as we would with any other object.

I personally use the @Valid annotation paired with hibernate validator.

so my spring controller would look like.

@PatchMapping("/customer/1")
public void updateCustomer(@RequestBody @Valid CustomerPatch updateRequest) {
}

public class CustomerPatch{
    @NotNull
    String cusotmerName;
}