java - 带有 JPAContainer 和 FieldGroup 的 Vaadin 7.0.1 组合框

Question

(对不起，如果这是一个新问题)

我有两个 JPAContainer，一个用于 Employee 类/表，一个用于 Language 类/表。员工可以选择语言。

我正在尝试创建一个员工编辑表单，其中包含用于语言选择的组合框和用于处理绑定(bind)和创建的 FieldGroup。

我可以通过 JPAContainer 获取下拉列表以包含 Languages 表中的条目，但它不会显示 Employee 记录中已有的值。我做错了什么？

//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;

    ... }

Answer 1

我通过 Vaadin 论坛回答了这个问题(感谢 Jonatan Kronqvist)收到了以下回复。

Hi Michael,

JPAContainer item IDs are the same as the ID in the database, which means that using a JPAContainer in a select/combo box causes the value of the select to be the ID of the row in the database and not the POJO itself, as is expected by your Employee entity POJO. Adding a SingleSelectConverter to your combo box should fix your problem:

language.setConverter(new SingleSelectConverter(language));

...

HTH, /Jonatan