Thymeleaf 和 #fields.hasErrors

Question

我正在为学校做这项作业。使用 SpringMVC、Hibernate JPA 和 Thymeleaf。下面的代码涉及一个名为“ stringGrade ”的特定属性。我想使用 Hibernate Validator 验证该字段中的输入。我似乎无法让 Thymeleaf 读懂这个表达式。在视图中循环的 arrayList 的名称属性为“deliverables[0].stringGrade”，依此类推，具体取决于有多少个。我尝试使用“ Deliverables[ ${stat.index} ].name ”，这会导致 Thymeleaf 失败并出现以下错误：

HTTP Status 500 - 请求处理失败；嵌套异常是 org.thymeleaf.exceptions.TemplateProcessingException：评估 SpringEL 表达式的异常：“#fields.hasErrors('deliverables[0].stringGrade')” (menuItems/inputGrades:33)

我想做的就是让 Thymeleaf 能够使用 #fields.HasErrors 和 #fields.error 读取值。下面是相关的代码：

成绩计算器型号：

public class GradeCalculator {

private ArrayList<Deliverable> deliverables;

可交付模型：

@Entity
@Table(name="Deliverables")
public class Deliverable implements Serializable {


@NotEmpty(message = "Required")
@Size(min = 1, max = 100, message = "Must be between 1 and 100")
@Digits(integer = 3, fraction = 0, message = "Must be a numeric value")
private String stringGrade; // String version of the grade ( Used for view input fields )

百里香叶视图：

<form th:object="${gradeCalculator}" action="#" th:action="@{/process/inputGrades}" method="POST" class="form-horizontal" role="form">

    <div th:each="deliverable,stat : ${grades.deliverables}">
        <div class="form-group">
            <p>Deliverable Name<span th:text="${grades.deliverables[__${stat.index}__].name}" name="name" id="name" class="badge tab-space"></span></p>
            <p>Deliverable Weight<span th:text="${grades.deliverables[__${stat.index}__].weight}" name="weight" id="weight" class="badge tab-space"></span></p>

            <h3><span class="label">Grade:</span></h3>

            <input type="text" th:field="${grades.deliverables[__${stat.index}__].stringGrade}" class="form-control" />
            <ul class="help-inline" th:if="${#fields.hasErrors('deliverables[__${stat.index}__].stringGrade')}">
                <li class="error" th:each="err : ${#fields.errors('deliverables[__${stat.index}__].stringGrade')}" th:text="${err}">Input is incorrect</li>
            </ul>
        </div>
    </div>

    <div class="form-group">
        <div class="text-center col-sm-10 col-sm-offset-2 col-md-4 col-md-offset-4">
                <button type="submit" class="btn btn-primary">Submit</button>
        </div>
    </div>

</form>

Answer 1

找到了答案。我没有使用 Thymeleaf 变量表达式正确处理“deliverables[ ${stat.index} ].stringGrade ”。我应该这样做：

<ul class="help-inline" th:if="${#fields.hasErrors('${grades.deliverables[__${row.index}__].stringGrade}')}">
    <li
      class="error"
      th:each="err : ${#fields.errors('${grades.deliverables[__${row.index}__].stringGrade}')}" 
      th:text="${err}">
        Input is incorrect
    </li>
</ul>