Thymeleaf: Concatenation - Could not parse as expression
But from what I see you have quite a simple error in syntax
<p th:text="${bean.field} + '!' + ${bean.field}">Static content</p>the correct syntax would look like
<p th:text="${bean.field + '!' + bean.field}">Static content</p>As a matter of fact, the syntax th:text="'static part' + ${bean.field}" is equal to th:text="${'static part' + bean.field}".
Try it out. Even though this is probably kind of useless now after 6 months.