JSF管理bean EJB注入 [英] JSF managed-bean EJB injection

问题描述

我在企业应用程序模块中有一个EJB（PersonManager），它注入另一个EJB（Person）：

  @Stateful 
 public class PersonManager实现PersonManagerLocal {
 @EJB 
 private PersonLocal person; 
 
 @Override 
 public void setPersonName（String name）{
 person.setName（name）; 
} 
 
 @Override 
 public String getPersonName（）{
 return person.getName（）; 
} 
} 
  

我想在JSF网页中使用PersonManager EJB应用程序。我在faces-config.xml中定义它：

 < managed-bean> 
< managed-bean-name> personManager< / managed-bean-name> 
< managed-bean-class> ejb.PersonManager< / managed-bean-class> 
< managed-bean-scope> session< / managed-bean-scope> 
< / managed-bean> 
  

问题是，注入PersonLocal EJB不会发生。 person属性始终为NULL。我怎么了？

但是，如果我将一个JSF管理的bean中的PersonManager注入到这个文件中：

  @ManagedBean 
 @RequestScoped 
 public class Index {
 @EJB 
 private PersonManagerLocal personManager; 
 .... 
  

IT WORKS。我需要第一种情况，请帮助我：-D

解决方案

您正在混合EJB和JSF托管bean的职责。 faces-config.xml 仅注册JSF工件，例如受管Bean而不是EJB。您在 faces-config.xml中的注册

 < managed-bean> ; 
< managed-bean-name> personManager< / managed-bean-name> 
< managed-bean-class> ejb.PersonManager< / managed-bean-class> 
< managed-bean-scope> session< / managed-bean-scope> 
< / managed-bean> 
  

基本上与

  @ManagedBean 
 @SessionScoped 
 public class PersonManager {
 // ... 
} 
 换句话说，您正在将该类注册为JSF托管的bean，该bean可以通过＃{personManager} 。这不代表与EJB容器管理的实例相同的实例。您可以并且应该不使用 faces-config.xml 注册EJB。您可以使用 javax.ejb 包中的注释，例如 @Stateless 和 @Stateful 。这就是注册一个EJB所需要的。
 
 
 
实际上，在 faces-config.xml 中注册JSF托管bean是JSF 2.x中的旧JSF 1.x方式已被新的 @ManagedBean 注释所取代。
 
 
 
 
 
 
 更新 p> 
 
 
 < h：form> 
< h：inputText value =＃{personManager.person.name}/> 
 ... 
< h：commandButton value =保存action =＃{personManager.save}/> 
< h：messages /> 
< / h：form> 
  
控制器（JSF托管bean）：
  @ManagedBean 
 @ViewScoped 
 public class PersonManager implements Serializable {
 
 private Person person; 
 
 @EJB 
私人PersonService personService; 
 
 @PostConstruct 
 public void init（）{
 person = new Person（）; 
} 
 
 public void save（）{
 personService.create（person）; 
 FacesContext.getCurrentInstance（）。addMessage（null，
 new FacesMessage（Person successfully created，new ID is+ person.getId（）））; 
} 
 
 // ... 
} 
  
 Model（JPA实体）：
  @Entity 
 public class Person implements Serializable {
 
 @Id 
 private Long id; 
 
 private String name; 
 
 // ... 
} 
  
服务无状态EJB）：
  @Stateless 
 public class PersonService {
 
 @PersistenceContext 
 private EntityManager em; 
 
 public void create（Person person）{
 em.persist（person）; 
} 
 
 // ... 
} 
  
 
I have an EJB (PersonManager) in the Enterprise Application modul, which injects another EJB (Person):
@Stateful
public class PersonManager implements PersonManagerLocal {
    @EJB
    private PersonLocal person;

    @Override
    public void setPersonName(String name) {
        person.setName(name);
    }

    @Override
    public String getPersonName() {
        return person.getName();
    }
}
I want to use the PersonManager EJB in a JSF web app. I define it in the faces-config.xml:
<managed-bean>
    <managed-bean-name>personManager</managed-bean-name>
    <managed-bean-class>ejb.PersonManager</managed-bean-class>
    <managed-bean-scope>session</managed-bean-scope>
</managed-bean>
The problem is that, the injection of the PersonLocal EJB doesn't happen. The person property is always NULL. What did I wrong?

But if I inject the PersonManager in a JSF managed bean like this:
@ManagedBean
@RequestScoped
public class Index {
    @EJB
    private PersonManagerLocal personManager;
    ....
IT WORKS. I need the first scenario, please help me :-D
解决方案
You are mixing the responsibilities of EJBs and JSF managed beans. The faces-config.xml registers only JSF artifacts, such as managed beans and not EJBs. Your registration in faces-config.xml
<managed-bean>
    <managed-bean-name>personManager</managed-bean-name>
    <managed-bean-class>ejb.PersonManager</managed-bean-class>
    <managed-bean-scope>session</managed-bean-scope>
</managed-bean>
does basically exactly the same as 
@ManagedBean
@SessionScoped
public class PersonManager {
    // ...
}
In other words, you're registering the class as a JSF managed bean which is available in views by #{personManager}. This does not represent the same instance as is managed by the EJB container. You can and should not use faces-config.xml to register EJBs. There you use the annotations from the javax.ejb package for, such as @Stateless and @Stateful. That's all you need to register an EJB.

Actually, registering JSF managed beans in faces-config.xml is an old JSF 1.x way which has in JSF 2.x been replaced by the new @ManagedBean annotation.



Update the proper approach would be:

View (the Facelets file):
<h:form>
    <h:inputText value="#{personManager.person.name}" />
    ...
    <h:commandButton value="Save" action="#{personManager.save}" />
    <h:messages />
</h:form>
Controller (the JSF managed bean):
@ManagedBean
@ViewScoped
public class PersonManager implements Serializable {

    private Person person;

    @EJB
    private PersonService personService;

    @PostConstruct
    public void init() {
        person = new Person();
    }

    public void save() {
        personService.create(person);
        FacesContext.getCurrentInstance().addMessage(null,
            new FacesMessage("Person successfully created, new ID is " + person.getId()));
    }

    // ...
}
Model (the JPA entity):
@Entity
public class Person implements Serializable {

    @Id
    private Long id;

    private String name;

    // ...
}
Service (the stateless EJB):
@Stateless
public class PersonService {

    @PersistenceContext
    private EntityManager em;

    public void create(Person person) {
        em.persist(person);
    }

    // ...
}


                        
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