jsf - JPA实体作为JSF Bean？

Question

使用实体作为JSF支持Bean是否有意义？

@Entity
@ManagedBean
@ViewScoped
public class User {

    private String firstname;
    private String lastname;

    @EJB
    private UserService service;

    public void submit() {
        service.create(this);
    }

    // ...
}

还是将它们分开保存并在最后将数据从支持Bean传输到实体是更好的选择？

@ManagedBean
@ViewScoped
public class UserBean {

    private String firstname;
    private String lastname;

    @EJB
    private UserService service;

    public void submit() {
        User user = new User();
        user.setFirstname(firstname);
        user.setLastname(lastname);
        service.create(user);
    }

    // ...
}

Answer 1

您可以这样做。从技术上讲这是可能的。但这在功能上没有任何意义。您基本上是在将模型与 Controller 紧密耦合。通常，JPA实体(模型)是JSF受管bean( Controller )的属性。这将保留代码DRY。您不想在所有地方都复制相同的属性，更不用说对这些属性的注释了，例如bean验证约束。

例如。

@ManagedBean
@ViewScoped
public class Register {

    private User user;

    @EJB
    private UserService service;

    @PostConstruct
    public void init() { 
        user = new User();
    }

    public void submit() {
        service.create(user);
    }

    public User getUser() {
        return user;
    }

}

使用此Facelets页面( View ):

<h:form>
    <h:inputText value="#{register.user.email}" />
    <h:inputSecret value="#{register.user.password}" />
    <h:inputText value="#{register.user.firstname}" />
    <h:inputText value="#{register.user.lastname}" />
    ...
    <h:commandButton value="Register" action="#{register.submit}" />
</h:form>

也可以看看:

What components are MVC in JSF MVC framework?

JSF Controller, Service and DAO

Contradictory explanations of MVC in JSF

JSF 2 reusing the validation defined in the JPA entities?

why shouldn't entity bean be managed by JSF framework?