Thymeleaf th:if with null error

Question

I'm trying to populate a thymeleaf template with some data from Spring Boot. What I'm trying to do is this

<tr th:if="${group.organization}">
    <td class="col_title"><b>Organization:</b></td>
    <td class="organization-field-content" th:text="${group.organization}"></td>
</tr>

I've tried both the solutions proposed here: Thymeleaf: show text if the attribute and property exists and, following the render order of thymeleaf, since the group.organization is null, the entire inner tds should not be displayed.

Still there a problem because Thymeleaf complains saying

Servlet.service() for servlet [dispatcherServlet] in context with path [] 
threw exception [Request processing failed; nested exception is 
org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating 
SpringEL expression: "group.organization" (group)] with root cause
java.lang.NullPointerException: null

I don't understand why this is happening, since the group object exists, just the organization is null

is `organization` a `boolean` property? If not, it makes more sense to do: ` Organization: ` — riddle_me_this, Sep 14 '16 at 18:29

score 0 · Answer 1 · answered Sep 14 '16 at 17:02

0

You may confirm if really your group object is not null by just dumping it in a span something like <span th:utext="${group}" />

answered Sep 14 '16 at 17:02

mhasan

3,703
1
18
37

score 0 · Answer 2 · answered Sep 15 '16 at 05:09

Maybe try the following to check whether group and organisation are not null before showing the div.

<tr th:if="${group != null && group.organization != null}">
    <td class="col_title"><b>Organization:</b></td>
    <td class="organization-field-content" th:text="${group.organization}"></td>
</tr>

score 0 · Answer 3 · answered Sep 15 '16 at 08:47

Thanks for all the replies, turned out the problem was somewhere else in the end.

All the proposed solution were still giving the same problem, and that was because of a method inside the Group Spring-data Model. Indeed the null pointer exception came out of the getOrganization method, which wasn't serializing correctly the null value.

Maybe this can help someone else in the future

Thymeleaf th:if with null error

3 Answers3