JSR303注释@pattern不起作用

Question

Im using a JSR303 annotation @Pattern on a field to check for String that contains whitespaces only. If whitespaces only are found then throw a message however the @Pattern is not working

@Length(max = AlertConstants.LENGTH_FOR_TWITTER_TEXTS, message = "{twitter.message.max}")
@Pattern(regexp ="^\\s*$", message = "{message.twitter.content.not.empty}")
private String twitterChannelContent = "";

im using @length as above which is working fine. Please suggest

Answer 1

There are two possibilities:

• Either you misunderstand the function of the "^" character, it performs a "not" when enclosed in brackets, however as you have written it, it indicates the start of the string.

• Or you mistunderstand the function of the Pattern annotation. It will validate that the string matches the given pattern and if not, it uses the error message.

Either way, currently you are saying that the string should only contain whitespaces.

Answer 2

Allow space back and forth : ([^^$]|^\\s*\\S+\\s*$)

No spaces : ([^^$]|^\\S+$)

Troubleshooting point : [^ WOW ] - Denied "WOW"