In the previous post you could learn how to create a basic custom constraint annotation compatible with the Bean Validation standard. This demo will extend the former post by explaining how to create constraints which are more flexible due to parameters defined for particular use cases. If you’re totally unfamiliar with the topic, I refer you to the aforementioned post to grasp the essentials. Otherwise, just keep reading.
Although built-in validation support in Spring is largely sufficient for standard use cases, sooner or later every developer runs into a situation when the sets of validation annotations provided by JSR 303 or Hibernate Validator are not enough. In this post you will learn how to create a simple constraint annotation served by a custom validator with access to the Spring context of a Spring Boot application.