JSF @managedproperty 和 @PostConstruct

我对 JSF2 @ManagedProperty 注释有疑问。我有一个创建用户的托管 bean，然后我想将该用户传递给另一个 bean 以显示与该用户相关的其他信息。所以我的代码如下:

@Named("userController")
@SessionScoped
public class UserController implements Serializable {

@EJB
private session.UserFacade ejbFacade;
private List<User> items = null;
private User selected;
private User utente;
private String user;
private String pass;
----getter and setter----

在 Schedule Bean 中，我在 @PostConstruct 中使用 userController bean:

@Named(value = "scheduleController")
@SessionScoped
public class ScheduleController implements Serializable {

private ScheduleModel eventModel;  

private ScheduleEvent event = new DefaultScheduleEvent();

@EJB
ActivityFacade ejbFacade;

@ManagedProperty(value="#{userController}")
private UserController credentials;


public ScheduleController() {        
}

@PostConstruct
public void init(){
    eventModel = new DefaultScheduleModel();       
    List<Activity> daFare =ejbFacade.findForUser(credentials.getUtente().getIdUser());
    for(int i=0;i<daFare.size();i++){
        eventModel.addEvent(new DefaultScheduleEvent(daFare.get(i).getDescrizione(),daFare.get(i).getDalleOre(),daFare.get(i).getAlleOre() ));
    }
}

public void setCredentials(UserController credentials) {
    this.credentials = credentials;
}

当我调试代码时，我发现 UserController 凭据始终为空......出了什么问题？我需要在 faces-config.xml 中指定一些内容？非常感谢您的提示。

编辑:

使用@Inject更改@ManagedProperty并在WEB-INF文件夹中添加以下beans.xml后，问题仍然存在。

<?xml version="1.0" encoding="UTF-8"?>
   <beans xmlns="http://java.sun.com/xml/ns/javaee"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
   xsi:schemaLocation="http://java.sun.com/xml/ns/javaee    http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">

该应用程序的工作方式如下: 用户可以通过此 xhtml 页面登录:

<body>
    <h:form>  
        <p:growl id="msgs" showDetail="true" />
        <p:panel header="Inserisci i tuoi dati" style="margin: 0 auto; text-align: center" >
            <h:panelGrid columns="2" cellpadding="5" style="margin: 0 auto; text-align: center">
                <p:outputLabel value="Username"/>
                <p:inputText value="#{userController.user}"  required="true" label="Username"   size="40"/>
                <p:outputLabel value="Password" />
                <p:password  value="#{userController.pass}"  required="true" label="Password" size="40"/>
                <p:commandButton action="#{userController.validateLogin}" value="Login"  update="msgs" ajax="false" style="text-align: center"/>
            </h:panelGrid>
        </p:panel>         
    </h:form>

</body>

提交表单后，userController 验证该特定用户是否存在于数据库表中，然后实例化 User utente( id、用户名、密码、电子邮件作为字段)。之后，应用程序重定向到 home.xhtml，显示多个用户的信息，并选择由用户 id 选择的数据库表的多个信息。这是我设置 User utente 的代码:

public String validateLogin(){

    String output="home";
    boolean exist=false;
    exist=ejbFacade.logValid(user,pass);
    if(!exist){
        //FacesContext.getCurrentInstance().getExternalContext().invalidateSession();
        FacesContext context = FacesContext.getCurrentInstance();
        context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO,"Username o Password errata","Contattare l'amministratore"));             
        return "index";
    }else{
        utente=ejbFacade.setUtente(user);  
        FacesContext context = FacesContext.getCurrentInstance();          
        context.addMessage(null, new FacesMessage("Accesso eseguito con successo.","Bentornato " + user));
        return output;
    }
}

我控制用户存在并设置utente的代码顺序是:

@Stateless
public class UserFacade extends AbstractFacade<User> {
@PersistenceContext(unitName = "ImmobiliareWebPU")
private EntityManager em;

@Override
protected EntityManager getEntityManager() {
    return em;
}

public UserFacade() {
    super(User.class);
}

public boolean logValid(String user, String pass) {
    List<User> utente ;
    boolean autorizzato;
    String find = "User.findByUsername&Password";
    Query query = em.createNamedQuery(find, User.class);
    query.setParameter("username", user);
    query.setParameter("password", pass);
    utente =query.getResultList();
    if (utente.isEmpty()) {
        autorizzato=false;           
    }
    else{
       autorizzato=true;                      
    }
    return autorizzato;
}

public User setUtente(String user) {
    //SETTO L'UTENTE PER LA SESSIONE DEL PROGRAMMA
    User utente;
    String find = "User.findByUsername";
    Query query = em.createNamedQuery(find, User.class);
    query.setParameter("username", user);       
    utente =(User) query.getSingleResult();

    return utente;
}

}

我需要用户信息的代码是:

@Named(value = "scheduleController")
@RequestScoped
public class ScheduleController implements Serializable {

private ScheduleModel eventModel;  

private ScheduleEvent event = new DefaultScheduleEvent();

@EJB
ActivityFacade ejbFacade;

@Inject
private UserController credentials;


public ScheduleController() {        
}

@PostConstruct
public void init(){
    eventModel = new DefaultScheduleModel();       
    List<Activity> daFare =ejbFacade.findForUser(credentials.getUtente().getIdUser());
    for(int i=0;i<daFare.size();i++){
        eventModel.addEvent(new DefaultScheduleEvent(daFare.get(i).getDescrizione(),daFare.get(i).getDalleOre(),daFare.get(i).getAlleOre() ));
    }
}

在 ejbFacade 中我做了一个简单的查询:

@Stateless
public class ActivityFacade extends AbstractFacade<Activity> {
@PersistenceContext(unitName = "ImmobiliareWebPU")
private EntityManager em;

@Override
protected EntityManager getEntityManager() {
    return em;
}

public ActivityFacade() {
    super(Activity.class);
}

public List<Activity> findForUser(int utenteId) {
    //RICHIEDO LE ATTIVITA' DEL SINGOLO UTENTE
    List<Activity> daFare ;
    String find = "Activity.findByUserId";
    Query query = em.createNamedQuery(find, Activity.class);
    query.setParameter("idUser", utenteId);
    daFare =query.getResultList();

    return daFare;
}

}

在 Debug模式下，我看到 UserController 的实例全部为空字段；这似乎是 UserController 的一个新版本。我还使用“import javax.enterprise.context.SessionScoped”。我的错在哪里？

最佳答案

When i debug the code, I see that the UserController credentials is always null.... What's wrong?

请注意您混淆了 CDI (Context and Dependency Injection)具有托管属性，这可能会导致所描述的行为。您的 Bean 使用 @Named 进行注释，而不是 @ManagedBean，因此:

    @ManagedProperty(value="#{userController}")
    private UserController credentials;

应替换为:

    @Inject
    private UserController credentials;

有关 CDI 和支持 bean 之间差异的真正精彩解释，请参阅本主题中的 @BalusC 答案:Backing beans (@ManagedBean) or CDI Beans (@Named)? .

I need to specify something in faces-config.xml?

不，但您应该包含一个beans.xml，如下例所示:Packaging CDI applications 。据我记得，无论发现模式如何，此文件都是必需的。以下是您可以在 NetBeans 中自动生成的 beans.xml:

新文件 --> 上下文和依赖注入(inject) --> beans.xml(CDI 配置文件)。

这就是我让 CDI 工作所需要的一切:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
       bean-discovery-mode="annotated">
</beans>

关于JSF @managedproperty 和 @PostConstruct，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26241197/

JSF @managedproperty 和 @PostConstruct

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