与 thymeleaf 并行迭代两个列表

Question

在我当前的 spring-boot 项目中，我有这个 thymeleaf 代码：

<th:block th:each="item : ${menu}">
...
              <a th:href="@{/__${menu2}__/listagem}">
                  <i class="icon-asterisk"></i>
                  <span th:utext="${item}"></span>
              </a>
...
<th:block>

我尝试在单个循环中迭代两个列表（menu 和 menu2）th:each。对于 menu2 我试试这个：

${menu2[itemStat.index]}

但我收到错误消息：

org.springframework.expression.spel.SpelEvaluationException: EL1012E:(pos 5): Cannot index into a null value

在循环中访问第二个列表的正确方法是什么？

更新

控制器：

@ModelAttribute("menu")
public List<String> menu() throws Exception {
    return ApplicationClasses.lista_classes_projeto();
}
@ModelAttribute("menu2")
public List<Class<?>> menu2() throws Exception {
    return ApplicationClasses.lista_classes_projeto_2();
}

应用程序类：

public static List<String> lista_classes_projeto() throws ClassNotFoundException {
Locale currentLocale = Locale.getDefault();
    ResourceBundle messages = ResourceBundle.getBundle("messages", currentLocale);

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

ClassPathScanningCandidateComponentProvider scanner = new ClassPathScanningCandidateComponentProvider(false);
scanner.addIncludeFilter(new AnnotationTypeFilter(Form.class));
for (BeanDefinition bd : scanner.findCandidateComponents("com.spring.loja.model")) {
  Class<?> clazz = Class.forName(bd.getBeanClassName());
  lista.add(messages.getString(clazz.getSimpleName()));
}

return lista;
}

public static List<Class<?>> lista_classes_projeto_2() throws ClassNotFoundException {
List<Class<?>> lista = new ArrayList<Class<?>>();

ClassPathScanningCandidateComponentProvider scanner = new ClassPathScanningCandidateComponentProvider(false);
scanner.addIncludeFilter(new AnnotationTypeFilter(Form.class));
for (BeanDefinition bd : scanner.findCandidateComponents("com.spring.loja.model")) {
  Class<?> clazz = Class.forName(bd.getBeanClassName());
  lista.add(clazz);
}

return lista;
}

Answer 1

没有更多细节，我在提供这个答案时做出了很大的假设。

<block th:each="item,itemStat : ${menu}">
<span th:text="*{menu2[__${itemStat .index}__].something}"></span>  // assuming its a object that has parameter called somethin
</block>

我认为您的菜单 2 列表是空的，因此也是空的。

与 thymeleaf 并行迭代两个列表

Iterating two list in parallel with thymeleaf

spring

loops

thymeleaf

spring-boot