Persist radio checked value in Thymeleaf Spring - spring

Question

When searching, if we select a given field to search within and submit, our choice is forgotten. How could someone modify the view template to keep the previous search field selected when displaying results?
I have read many other SO questions and the thymeleaf documentation here but have not found a suitable answer yet.
One can hard code a string (like employer) with the following:
search.html snippet
<span th:each="column : ${columns}">
<input
type="radio"
name="searchType"
th:id="${column.key}"
th:value="${column.key}"
th:checked="${column.key == 'employer'}"/>
<label th:for="${column.key}" th:text="${column.value}"></label>
</span>
SearchController.html snippet
#RequestMapping(value = "")
public String search(Model model) {
model.addAttribute("columns", columnChoices);
return "search";
}
How can I persist the user selected radio value upon POST in Thymeleaf Spring?
(and default to the first, value on the GET)

Answer 1

http://www.thymeleaf.org/doc/tutorials/3.0/thymeleafspring.html#creating-a-form
Command object.
public class Search {
// default "employer"
private String type = "employer";
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
}
Controller
#GetMapping
public String search(Model model) {
model.addAttribute("columns", columnChoices);
model.addAttribute("search", new Search());
return "search";
}
#PostMapping
public String search(#ModelAttribute Search search) {
// Search's attributes match form selections.
}
With search as your command object, a radio buttons should look like this:
<form th:object="${search}">
<th:block th:each="column: ${columns}">
<input type="radio" th:value="${column.key}" th:id="${column.key}" th:field="*{type}" />
<label th:for="${column.key}" th:text="${column.value}" />
</th:block>
</form>