thymeleaf Expression Utility Objects String length
Example
<div th:if="*{userMessage!=null and #strings.length(userMessage)>0}">
<label th:text = "*{userMessage}"/>
</div>
<div th:if="*{userMessage!=null and #strings.length(userMessage)>0}">
<label th:text = "*{userMessage}"/>
</div>
