嗨，我想用 thyleaf 填充 html 的 select 并出现错误

Question

I want to fill a select with a Map as ModelAttribute but when I execute the app and try load my load appears a error.

java.lang.IllegalStateException: Invalid target for Validator [com.bolsadeideas.springboot.form.app.validation.UserValidator@2343043c]: España at org.springframework.validation.DataBinder.assertValidators(DataBinder.java:542) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE] at org.springframework.validation.DataBinder.addValidators(DataBinder.java:553) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE] at com.bolsadeideas.springboot.form.app.controller.FormController.initBinder(FormController.java:54) ~[classes/:na]

My html is this

<form th:action="@{/form}" method="post" th:object="${user}">
    <div>
        <label for="country">Country</label>
    </div>
    <div>
        <select id="country" th:field="*{country}">
            <option value="">--Select Country--</option>
            <option th:each="country: ${countriesMap.entrySet()}"
                th:text="${country.value}" th:value="${country.key}"></option>
        </select>
    </div>
    <div th:if="${#fields.hasErrors('country')}" th:errors="*{country}"></div>

and my controller code:

@InitBinder // elemento del ciclo de vida del controlador
public void initBinder(WebDataBinder binder) {

    binder.addValidators(validator);
    // CustomEditor cuztomizar un campo que obtemenos y convertirlo en otro tipo de
    // dato es como un filtro
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
    // Eso es la indulgencia, es decir, define si en analizdor que va a realizar un
    // análisis un (parse) de la fecha con false se vuelve mas estricto
    dateFormat.setLenient(false);
    binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));

}// llenando la vista Select con un Map
@ModelAttribute("countriesMap")
public Map<String, String> countriesMap() {
    Map<String, String> countries = new HashMap<String, String>();
    countries.put("ES", "España");
    countries.put("MX", "México");
    countries.put("CL", "Chile");
    countries.put("EC", "Ecuador");
    countries.put("CO", "Colombia");
    countries.put("BO", "Bolivia");
    countries.put("FR", "Francia");
    return countries;
}

before I did not have problems using a simple List of java.util

Answer 1

@PostMapping("/form")
public String procesar(@Valid User user, BindingResult bindingResult, Model model, SessionStatus status) {
    // asi validamos de forma explicita
    // validator.validate(user, bindingResult);
    model.addAttribute("title", "Resultado Form");
    if (bindingResult.hasErrors()) {
        return "form";
    }
    model.addAttribute("user", user);
    /**
     * completa el proceso manejo de datos y elimina los atributos u objetos
     * almacenados en la sesion
     */
    status.setComplete();
    return "resultform";
}

I had model.addAttribute("user", "España"); was error type