java - 如果测试不显示代码部分 - spring mvc

Question

我的 jsp 中有一个区域，我想通过测试列表是否不为空来显示部门列表。这是我的 addDeparment.jsp 文件中的代码

<c:if test="${!empty departments}">
    <table align="center" border="1">
        <tr>
            <th>Department ID</th>
            <th>Department Name</th>
            <th>Options</th>
        </tr>

        <c:forEach items="${departments}" var="department">
            <tr>
                <td><c:out value="${department.departmentId}"/></td>
                <td><c:out value="${department.departmentName}"/></td>
                <td align="center"><a href="editDepartment?departmentId=${department.departmentId}">Edit</a> | <a href="deleteDepartment?departmentId=${department.departmentId}">Delete</a></td>
            </tr>
        </c:forEach>
    </table>
</c:if>

这是获取所有部门并将它们附加到 HashMap 集合中的 Controller

@RequestMapping(value = "/addDepartment", method = RequestMethod.GET)
    public ModelAndView addCategory(@ModelAttribute("command")  Department department,
            BindingResult result) {
        Map<String, Object> model = new HashMap<String, Object>();
        model.put("departments",  departmentService.getDepartments());
        return new ModelAndView("addDepartment");
    }

如果我运行代码，jsp 文件中的 View 的这一部分不会显示

<tr>
            <th>Department ID</th>
            <th>Department Name</th>
            <th>Options</th>
        </tr>

无法弄清楚可能出了什么问题。

Answer 1

在 Controller 中，您需要将模型传递给 ModelAndView 对象，如下所示:

return new ModelAndView("addDepartment", model);

引用文献:

http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/servlet/ModelAndView.html#ModelAndView-java.lang.String-java.util.Map-