Spring How to update database entites from dropdown lists thymeleaf - spring

Question

So I need to update the entities in my table with the selected values from dropdown lists from thymeleaf.
What I want to do is update the movie column based on the selections from dropdown list. But I have more than one dropdown list for each WeekMovie entity.
I cant figure out how to update them all.
My WeekMovies Class
#Entity
public class WeekMovies {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
#ManyToOne
#JoinColumn(name="movie_id")
private Movie movie;
#ManyToOne
#JoinColumn(name="saloon_id")
private Saloon saloon;
//getter setters.
My Controller
#RequestMapping(value = "/update",method= RequestMethod.GET)
public String updateweekmovies(Model model){
List<WeekMovies> weekMoviesList = weekMovieService.findAll();
List<Movie> movieList= movieService.findAll();
model.addAttribute("weekMovieList",weekMoviesList);
model.addAttribute("movieList",movieList);
return "updateweekmovies";
}
#RequestMapping(value = "/update",method= RequestMethod.POST)
public String updateweekPost(Model model){
return "updateweekmovies";
}
My Thymeleaf
div class="container">
<div class="row">
<form class="form-horizontal" th:action="#{/week/update}" method="post"
enctype="multipart/form-data">
<fieldset>
<legend class="center-block">
Update Book Information<span style="font-size: small"> * is a
required field</span>
</legend>
<!-- category -->
<div class="form-group">
<label class="col-md-2 control-label" for="weekmovie">*
Category</label>
<div class="col-md-8">
<li th:each="weekmovie:${weekMovieList}">
<select th:value="${weekmovie.movie}" id="weekmovie" name="weekmovie" class="form-control">
<option value="" selected="selected" disabled="disabled">Please
select an option...</option>
<option th:each="movie:${movieList}" th:value="${movie.id}" th:text="${movie.title}"> </option>
</select>
</li>
</div>
</div>
<div class="form-group">
<div class="col-md-2"></div>
<div class="col-md-8">
<button type="submit" class="btn btn-success">Update Movie</button>
</div>
</div>
</fieldset>
</form>
</div>