How to convert HTML table to List using Thymeleaf - spring-mvc

Question

I am creating an spring-boot MVC web application.
When I get the contents from the controller I can display them correctly on the view. The content is an object with a List. The list is displayed on a table.
<form th:action="#{/}" th:object="${homeVO}" method="post">
<div align="center">
<table width="80%" id="sectionsTable">
<thead>
<th width="10%"><label class="tableTextTitle">ORDER</label></th>
<th width="50%"><label class="tableTextTitle">TITLE</label></th>
<th width="10%"></th>
<th width="10%"><label class="tableTextTitle">HIDE</label></th>
<th width="10%"></th>
<th width="10%"></th>
</thead>
<tbody>
<tr th:each="section, stat :${homeVO.sections}">
<td>
<input type="number" th:value="${section.id}" hidden="true" id="sectionid" />
<input type="number" class="form-control" th:value="${section.position}" id="position"/>
</td>
<td>
<input type="text" class="form-control" th:value="${section.name}" disabled="true" id="name"/>
</td>
<td align="center">
<a th:href="#{./sectionprofile(id=${section.id})}" class="btn btn-default">EDIT</a>
</td>
<td>
<input type="text" class="form-control" th:value="${section.column}" id="column"/>
</td>
<td>
<select class="form-control" id="condition">
<option value="0" th:selected="(${section.condition} == 0)"/>
<option value="1" th:text="#{minor}" th:selected="(${section.condition} == 1)"/>
<option value="2" th:text='#{minorEq}' th:selected="(${section.condition} == 2)"/>
<option value="3" th:text="#{different}" th:selected="(${section.condition} == 3)"/>
<option value="4" th:text='#{equals}' th:selected="(${section.condition} == 4)"/>
<option value="5" th:text='#{biggerEq}' th:selected="(${section.condition} == 5)"/>
<option value="6" th:text='#{bigger}' th:selected="(${section.condition} == 6)"/>
</select>
</td>
<td>
<input type="text" class="form-control" th:value="${section.criteria}" id="criteria"/>
</td>
</tr>
</tbody>
</table>
</div>
<div class="col-md-12">
Add Section
<input type="submit" class="btn btn-default" value="SAVE" />
</div>
</form>
When I change some values on the table I want to save them. When I save, I get in the controller the object with an empty List.
#RequestMapping(method = RequestMethod.POST)
public String set(HomeVO homeVO, Model model) {
if (homeVO != null) {
for (SectionVO sectionVO : homeVO.getSections()) {
Section section = sectionRepository.findOne(sectionVO.getId());
section.setPosition(sectionVO.getPosition());
section.setColumn(sectionVO.getColumn());
section.setCondition(sectionVO.getCondition());
section.setCriteria(sectionVO.getCriteria());
sectionRepository.save(section);
}
}
...
return "home";
}
What shall I do to get the table elements back into a List?

Answer 1

To accomplish this rows bindings properly follow the Thymeleaf Spring guide specificaly Dynamic Fields section. There is a special syntax so your HTML should be similar to this:
<tr th:each="row,rowStat : *{rows}">
<td th:text="${rowStat.count}">1</td>
<td>
<select th:field="*{rows[__${rowStat.index}__].variety}">
<option th:each="var : ${allVarieties}"
th:value="${var.id}"
th:text="${var.name}">Thymus Thymi</option>
</select>
</td>
<td>
<input type="text" th:field="*{rows[__${rowStat.index}__].seedsPerCell}" />
</td>
<td>
<button type="submit" name="removeRow"
th:value="${rowStat.index}" th:text="#{seedstarter.row.remove}">Remove row</button>
</td>
</tr>