瞬态检票口表格字段被忽略

Question

所以我有一个名为“用户”的实体

@Entity(name = "user")
@Audited
public class User extends DataObjectAudit {

    private static final long serialVersionUID = 1L;

    private Set<UserProjectCenterRole> roles = new HashSet<UserProjectCenterRole>();
    private RoleTypeEnum role = null;

    @OneToMany(mappedBy = "user", fetch = FetchType.LAZY, orphanRemoval = true)
    @Cascade(value = { CascadeType.MERGE, CascadeType.PERSIST, CascadeType.DELETE, CascadeType.SAVE_UPDATE })
    @Filters({ @Filter(name = "deletedFilter", condition = "deleted <> :deletedParam") })
    @NotAudited
    public Set<UserProjectCenterRole> getRoles() {
        return roles;
    }

    public void setRoles(Set<UserProjectCenterRole> roles) {
        this.roles = roles;
    }

    @Transient
    public RoleTypeEnum getRole() {
        return role;
    }

    @Transient
    public void setRole(RoleTypeEnum role) {
        this.role = role;
    }

}

这里是UserProjectCenterRole实体：

@Entity
@Table(name = "user_projectcenter_role")
public class UserProjectCenterRole extends DataObjectAudit {

    private static final long serialVersionUID = 1L;

    private User user = null;
    private ProjectCenter projectCenter = null;
    private RoleTypeEnum role = null;
    private Boolean active = null;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id")
    public User getUser() {
        return user;
    }

    @Basic
    public Boolean getActive() {
        return active;
    }

    @Enumerated(EnumType.STRING)
    public RoleTypeEnum getRole() {
        return role;
    }
}

在面板中，有一个下拉面板，其中用户的当前活动角色加载了“较低”的可能角色。选项是getRoles（）的结果，所选的选项应该加载到“role”属性中。

User sessionUser = StudySession.getSessionUser();
        List<RoleTypeEnum> roles = new ArrayList<RoleTypeEnum>();
        role.addAll(sessionUser.getActiveRole().getLowerAndEqualsThanSelf());

        WefDropDownPanel<RoleTypeEnum> role = 
                new WefDropDownPanel<RoleTypeEnum>(helper.of(RoleTypeEnum.class, "role").errorRequired(), //
                roles) //
                .setSizes(Size.S0, Size.S1, Size.S4);
        add(roles);

然后面板的onBeforeSave方法是：

@Override
    protected void onBeforeSave(AjaxRequestTarget target, WefForm<User> form) {
        super.onBeforeSave(target, form);

        User user = getModelObject();

        Set<UserProjectCenterRole> roles = user.getRoles();
        UserProjectCenterRole currentRole = null;
        if (!roles.isEmpty()) {
            currentRole = roles.iterator().next();
        }
        else {
            currentRole = new UserProjectCenterRole();
            roles.add(currentRole);
        }

        currentRole.setRole(user.getRole());
        currentRole.setUser(user);
        currentRole.setActive(true);
    }

但是在那时“getRole”返回null ......我无法猜到为什么......