This sample illustrates issues with performance that I am seeing when using the Spring HATEOAS library to add HAL resource links to REST responses.
Here is the output I am seeing when using ControllerLinkBuilder versus creating resource links manually:
Running org.example.myapi.HypertextLinksTest
5194 milliseconds to add 3 Spring HATEOAS links to 200 items USING ControllerLinkBuilder
12486 milliseconds to add 3 Spring HATEOAS links to 200 items USING ControllerLinkBuilder
22206 milliseconds to add 3 Spring HATEOAS links to 200 items USING ControllerLinkBuilder
3 milliseconds to add 3 Spring HATEOAS links to 200 items NOT USING ControllerLinkBuilder
2 milliseconds to add 3 Spring HATEOAS links to 200 items NOT USING ControllerLinkBuilder
2 milliseconds to add 3 Spring HATEOAS links to 200 items NOT USING ControllerLinkBuilder
As you can see, the simple act of using ControllerLinkBuilder to add resource links to 200 items incurs a severe performance penalty that seems to compound.
Simply run the included test with Maven, e.g.: mvn test