在SpringBoot中使用Thymeleaf的下拉列表

Question

I am trying to load drop down list using ArrayList in Springboot as i am new to springboot.

I have tried but not working as expected.

Please find the code which i have tried as below:

Java Code:

@Controller
public class DemoController {

@GetMapping("/create")
     public String create(Model model) {

      model.addAttribute("create", new Demo());

      return "create";

     }

     public void countriesList(Model model) {

          List<String> countryList = new ArrayList<>();

          countryList.add("US");
          countryList.add("UK");

          model.addAttribute("countries", countryList);

       }
}

HTML:

<form action="#" th:action="@{/create}" th:object="${create}" method="post">

        <select th:field="*{country}">
             <option value=""> -- </option>
             <option th:each="country : ${countries}" th:value="${country}" th:text="${country}"></option>
        </select>
</form>

Finally no errors but only loading in dropdown list with -- and not loading the countries.

Please help me on this.

Answer 1

You never called your function for adding countries to the model...

@Controller
public class DemoController {

 @GetMapping("/create")
 public String create(Model model) {

  model.addAttribute("create", new Demo());
  countriesList(model); // this line is needed
  return "create";

 }

 private void countriesList(Model model) {

  List < String > countryList = new ArrayList < > ();

  countryList.add("US");
  countryList.add("UK");

  model.addAttribute("countries", countryList);

 }
}

Answer 2

try with this code block

 <span th:each="country:${countries}" th:remove="tag">
          <option th:value="${country}" th:text="${country}"></option>
    </span>