I have set spring.data.web.pageable.serialization-mode: VIA_DTO, but the Page is not being transformed into a PagedModel.

[zhujianxintian]

🚨 IMPORTANT UPDATE (2026-08-27) 🚨

After further investigation, the issue described below is not caused by dependency configuration, but by a different underlying reason.
Please refer to this comment for the correct reproduction steps and the actual problem.
The original description below is kept for historical reference only.

---

Describe the bug

• I see that org.springdoc.core.configuration.SpringDocPageableConfiguration#pageOpenAPIConverter supports the EnableSpringDataWebSupport annotation.
• I also see that org.springdoc.core.customizers.DataRestDelegatingMethodParameterCustomizer#getName supports most of the properties of DataWebProperties, but it does not seem to call optionalSpringDataWebPropertiesProvider.get().getSpringDataWebProperties().getPageable().getSerializationMode() anywhere.

To Reproduce
Steps to reproduce the behavior:

• Spring Boot 4.1.0
• springdoc-openapi: 3.1.0 (springdoc-openapi-starter-webmvc-ui, springdoc-openapi-starter-webmvc-scalar)

spring:
  data:
    web:
      pageable:
        serialization-mode: VIA_DTO

@RestController
@RequestMapping("/api/users")
public class HelloController {

    @GetMapping
    public Page<UserInfo> listUserInfos() {
        List<UserInfo> userInfos = IntStream.range(0, 10).mapToObj(i -> new UserInfo("user" + i, "password" + i)).toList();
        return new PageImpl<>(userInfos);
    }

    public record UserInfo(String username, String password) {

    }

}

[jjh75607]

I tried this on Boot 4.1.0 with springdoc-openapi 3.1.0, using your controller and property, and the transformation does happen. The endpoint returns {"content":[...],"page":{"size":10,"number":0,"totalElements":10,"totalPages":1}} and springdoc documents it as PagedModelUserInfo.

There is one setup where I get what you are describing. If spring-data-commons is on the classpath but org.springframework.boot:spring-boot-data-commons is not, DataWebAutoConfiguration never runs, VIA_DTO has no effect, and springdoc falls back to PageUserInfo. Calling the endpoint in that state fails with HttpMessageNotWritableException: Could not write JSON: (was java.lang.UnsupportedOperationException).

If that matches your setup, it would explain what you are seeing.

[zhujianxintian]

Sorry, this issue does occur in my project, and I did check the source code but couldn't find this property being used there (maybe I didn't look carefully enough, or perhaps I missed it), so I just wrote a quick example to help reproduce it (not rigorous, I was being lazy).

That example did run correctly, so this time I wrote a complete demo to reproduce the situation.

demo.zip

The specific scenario is that using a custom wrapper class causes it to behave unexpectedly (but ResponseEntity works fine).

Thanks for your reminder. @jjh75607

[jjh75607]

@zhujianxintian thanks for the demo, it reproduces. I opened #3335 with a fix.

[zhujianxintian]

@jjh75607 Thank you very much for your contribution.