format nested object to table on thymeleaf - spring

Question

i build crm system,
i had object hes name users he hold also the data from details table (one to many realation)
lets says i had nested object name user and he had more than 1 object of details
i want to get this in the end in thymeleaf table
name | entry date
david | 5/6/22
david | 1/7/22
but i got
name | entry date
david | 5/6/22 , 1/7/22
this is table code on thymeleaf:
<table class="table w-75 table-striped table-dark table-hover">
<thead>
<tr>
<th scope="col" class="text-center">First name</th>
<th scope="col" class="text-center">Entry Date</th>
</tr>
</thead>
<tbody>
<tr th:each="users : ${ParkingUsers}">
<td class="text-center" th:text="${users.firstName}" />
<td class="text-center" th:each="date, i: ${users.parkingDetails}"
th:text="${(i.index > 0 ? '' : '') + date.entryDate}" />
</tr>
</tbody>
</table>
how can i fix that?
thanks

Answer 1

This is a good candidate for using the Thymeleaf th:block tag.
You can place the outer loop (for users) in this tag, and then place the inner loop (for parking details) in the <tr> tag.
Example:
Assume we have two classes:
public class User {
private String firstName;
private List<ParkingDetail> parkingDetails;
// getters and setters
}
And:
public class ParkingDetail {
private LocalDate entryDate;
// getters and setters
}
And assume we have a list of users: List<User>.
We can use the following in our Thymeleaf template:
<table class="table w-75 table-striped table-dark table-hover">
<thead>
<tr>
<th>First name</th>
<th>Entry Date</th>
</tr>
</thead>
<tbody>
<th:block th:each="user : ${users}">
<tr th:each="parkingDetail : ${user.parkingDetails}">
<td th:text="${user.firstName}"></td>
<td th:text="${parkingDetail.entryDate}"></td>
</tr>
</th:block>
</tbody>
</table>
This will generate the following HTML:
<table>
<thead>
<tr>
<th>First name</th>
<th>Entry Date</th>
</tr>
</thead>
<tbody>
<tr>
<td>david</td>
<td>2022-06-05</td>
</tr>
<tr>
<td>david</td>
<td>2022-07-01</td>
</tr>
</tbody>
</table>
The th:block tag allowed Thymeleaf to iterate over the list of users, but it did not cause any HTML to be generated. The Thymeleaf ${user} variable created in the th:block tag can be referenced in all the child tags inside the th:block.
There are various other examples of how th:block can be used, in other questions on this site - so if this does not meet your needs, you can research those other questions.