Using parameter 1 without using parameter 0 in Spring Boot messages

Question

In messages.properties file:

validation.title=At least {1} characters

Also LocalValidatorFactoryBean is defined:

@Bean
    public LocalValidatorFactoryBean localValidatorFactoryBean(MessageSource messageSource) {
        LocalValidatorFactoryBean bean = new LocalValidatorFactoryBean();
        bean.setValidationMessageSource(messageSource);
        return bean;
    }

When I run the code I get the result:

At least {1} characters

But if I change in properties:

validation.title=At least {1} characters {0}

I get the result:

At least 20 characters title

But I do not need the 0 parameters.

Is there a way to fix this?

Answer 1

You're trying to access array parameters and with this approach in order to get that done and have your string interpolated you need to use the one at the index 0 and I have no idea why. There's another way though and with common annotations (haven't tried this with custom annotations) for validating forms this can be solved as follows:

// the form

public class SomeForm {

  @Length(min = 4, max = 16, message="{username.length.error}")
  private String username;

// other stuff

}

In the messages.properties

username.length.error = Username cannot be blank and its length must be between {min} and {max} characters.

So in the message.properties (in this case {min} and {max}) the placeholders must match the names of the params you have on the annotation.