How to put validation on list of String coming from request in spring boot?

Question

I am creating Spring boot APIs and one of the API consumening data below:

class DataRequest{

    @Size(min=1, max=10)
    private String dataTitle;

    private List<String> emails;

}

How can we validate List like all strings must be valid emails or matching with some pattern by utilizing a validation framework in Spring controller using @Valid annotation?

Answer 1

Bean validation allows you to put the validating annotation inside the container type such as List. They refer this as the container element constraint validation.

So you can do something likes :

class DataRequest{

    @Size(min=1, max=10)
    private String dataTitle;

    private List<@Email String> emails;

}

or

class DataRequest{

    @Size(min=1, max=10)
    private String dataTitle;

    private List<@Pattern(regexp = "[A-Za-z\\d]*") String> emails;

}