Get the selected value in a select - option Thymeleaf and Spring Boot - html

Question

Im trying to generate a search options and in myweb page the user choose the value that is looking for this is my html code:
<table>
<tr>
<td><h2 align="left">Red Social: </h2></td>
<td>
<select th:field="*{redes}" name="redSoc">
<option th:each="r : ${redes}" th:value="${r.nombreRedSocial}"
th:text="${r.nombreRedSocial}"></option>
</select>
</td>
</tr>
<tr>
<td><input type="submit" value="Buscar"/></td>
</tr>
</table>
And this is my controller code:
#GetMapping("/RedesSociales")
public String infoPorRedSocial(Model model, #RequestParam(name = "redSoc", required = false) String redSoc) {
RedesSociales[] redes = redesService.obtenerTodasRedes();
model.addAttribute("redes", redes);
//model.addAttribute("grupo", null);
System.out.println(redSoc);
if (redSoc != null) {
System.out.println(redSoc);
model.addAttribute("info", infoService.obtenerTodosPorRedSocial(redSoc));
}
return "visual/reportes/ListarPorRedSocial";
}
Now as you can see im trying to get the value redSoc but im not sure how to the get this value from the selected option i tried several methods but didnt work.
EDIT:
I was using this code:
<form action="/RedesSociales" method="GET">
<h2 align="left">Red Social: </h2>
<input type="text" name="redSoc"/> <br>
<input type="submit" value="Buscar"/>
</form>
But this was not usefull because the option would be insert by the user and i wanted to made it more dynamic thats why now im using the current values stored in the database

Answer 1

already solve the problem Change my code to this :
<table> <tr> <td><h2 align="left">Red Social: </h2></td>
<td> <select name="redSoc"> <option th:each="r : ${redes}" th:value="${r.nombreRedSocial}" th:text="${r.nombreRedSocial}">
</option>
</select> </td> </tr>
<tr> <td><input type="submit" value="Buscar"/></td> </tr> </table>