oneToMany 的 @NotEmpty 注释验证器

Question

所以我有以下模型：

@Entity
@Table(name = "Project")
public class Project implements java.io.Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "PROJECT_ID", unique = true, nullable = false)
    private int projectId;
    private String name;

    ...

    @ManyToOne
    @JoinColumn(name = "MANAGER_ID")
    @NotEmpty(message = "test")
    private User manager;
    ....
}

由于某种原因，“@NotEmpty”注释在以下情况下会出现以下错误 输入为空：

org.springframework.web.util.NestedServletException：请求处理失败；嵌套异常是 javax.validation.UnexpectedTypeException: HV000030: No validator could be found for type: com.springmvc.model.User.

我通过以下方式将我的值传递给后端：

<form:select path="manager" class="selectpicker form-control">
    <form:option value="" >Alle managers</form:option>
         <c:forEach var="manager" items="${managers}">
         <form:option value="${manager.userId}" >${manager.getUserDetail().firstName}               
                             ${manager.getUserDetail().lastName}</form:option>
         </c:forEach>
</form:select>

我做错了什么？

Answer 1

将@NotEmpty 替换为@NotNull，应该可以解决您的问题。