java - Vaadin 7.0.1组合框与JPAContainer和FieldGroup

(抱歉，这是一个新问题)

我有两个JPAContainer，一个用于Employee类/表，一个用于语言类/表。员工可以选择一种语言。

我正在尝试创建一个带有用于语言选择的组合框的Employee编辑表单，并使用FieldGroup来处理绑定和创建。

我可以通过JPAContainer下拉列表中包含Languages表中的条目，但是它不会显示Employee记录中已经存在的值。我究竟做错了什么？

//Key parts of code....

private JPAContainer<Employee> employees;
private JPAContainer<Language> languages;

FormLayout formLayout = new FormLayout();

formFieldGroup = new FieldGroup(employeeItem);

Field<?> firstName = formFieldGroup.buildAndBind("First name", "firstName");
Field<?> lastName = formFieldGroup.buildAndBind("Last name", "lastName");
Field<?> userName = formFieldGroup.buildAndBind("Username", "userName");
Field<?> fullName = formFieldGroup.buildAndBind("Full name", "fullName");
Field<?> initials = formFieldGroup.buildAndBind("Initials", "initials");

ComboBox language = new ComboBox("Language",languages);
language.setContainerDataSource(languages);
language.setItemCaptionPropertyId("languageName");
language.setFilteringMode(FilteringMode.CONTAINS);
language.setImmediate(true);

formFieldGroup.bind(language, "language");

firstName.addValidator(new BeanValidator(Employee.class, "firstName"));
lastName.addValidator(new BeanValidator(Employee.class, "lastName"));
firstName.addValidator(new BeanValidator(Employee.class, "userName"));
lastName.addValidator(new BeanValidator(Employee.class, "fullName"));
lastName.addValidator(new BeanValidator(Employee.class, "initials"));

formLayout.addComponent(userName);
formLayout.addComponent(fullName);
formLayout.addComponent(firstName);
formLayout.addComponent(lastName);
formLayout.addComponent(initials);
formLayout.addComponent(language);

 // A few details of the domain classes
@Entity
@Table(name="Employees")
public class Employee   extends BaseEntity
{
private static final long   serialVersionUID    = 1L;

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="EmployeeID")
private Integer     employeeID;

    ...

@ManyToOne
@JoinColumn(name="LanguageID",updatable=false)
private Language    language;
    ...}

@Entity
@Table(name="Languages")
public class Language  extends BaseEntity
{

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="LanguageID")
private Integer languageID;

@Column(name="LangaugeName")
private String  languageName;

    ... }

最佳答案

我在Vaadin论坛上回答了这个问题，我们收到了以下回复(感谢Jonatan Kronqvist)。

迈克尔，你好

JPAContainer项目ID与数据库中的ID相同，
表示在选择/组合框中使用JPAContainer会导致该值
select是数据库中行的ID，而不是POJO
雇员实体POJO所期望的。添加一个
SingleSelectConverter到您的组合框应该解决您的问题:

language.setConverter(new SingleSelectConverter(language));

...

HTH，/乔纳丹