集成jsf，spring，hibernate。如何将Spring bean注入JSF托管bean？

时间：2014-05-13 18:14:46

标签： java spring hibernate jsf java-ee

我正在使用框架JSF 2.1，Spring 3.1.1.Release，hibernate 3.2.1开发Java EE项目。现在我正处于整合三者的阶段。 构建成功，我使用tomcat服务器7.但我在头版上得到了这个例外。

Etat HTTP 500 -

type Rapport d''exception

message

description Le serveur a rencontré une erreur interne qui l''a empêché de satisfaire la requête.

exception

javax.servlet.ServletException
    javax.faces.webapp.FacesServlet.service(FacesServlet.java:422)
cause mère

java.lang.NullPointerException
    controller.AnneeBean.getListeAnnees(AnneeBean.java:15)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:601)
    javax.el.BeanELResolver.getValue(BeanELResolver.java:87)
    com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
    org.apache.el.parser.AstValue.getValue(AstValue.java:183)
    org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:185)
    com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
    javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
    javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
    javax.faces.component.UIData.getValue(UIData.java:731)
    javax.faces.component.UIData.getDataModel(UIData.java:1798)
    javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484)
    javax.faces.component.UIData.setRowIndex(UIData.java:473)
    com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
    javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820)
    javax.faces.component.UIData.encodeBegin(UIData.java:1118)
    javax.faces.component.UIComponent.encodeAll(UIComponent.java:1754)
    javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
    javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
    com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:401)
    com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
    com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
    com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
    javax.faces.webapp.FacesServlet.service(FacesServlet.java:410)
note La trace complète de la cause mère de cette erreur est disponible dans les fichiers journaux de Apache Tomcat/7.0.42.

休眠 的hibernate.cfg.xml 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/base?zeroDateTimeBehavior=convertToNull</property>
    <property name="hibernate.connection.username">root</property>
    <mapping resource="net/vo/Annee.hbm.xml"/>
  </session-factory>
</hibernate-configuration>

hibernate.reveng.xml中

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-reverse-engineering PUBLIC "-//Hibernate/Hibernate Reverse Engineering DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-reverse-engineering-3.0.dtd">
<hibernate-reverse-engineering>
  <schema-selection match-catalog="base"/>
  <table-filter match-name="annee"/>
</hibernate-reverse-engineering>

AnneeDao.java 

package dao;

import java.util.List;
import net.vo.Annee;

public interface AnneeDao {
    public List getAllAnnees();
    public Annee getAnnee(Integer id);
    public void insert(Annee annee);
    public void update(Annee annee);
    public void delete(Integer id);
}

AnneeHibernateDao.java 

package dao;

import java.util.List;
import net.vo.Annee;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class AnneeHibernateDao implements AnneeDao{
    private List<Annee> listeAnnees;
    private Annee annee;
    public void init()
    {
        System.out.println("Méthode d'initiation");
    }
    @Override
    public List getAllAnnees() {
        Session session=HibernateUtil.getSession();
        try
        {
            session.beginTransaction();
            listeAnnees = session.createQuery("from Annee").list();
            return listeAnnees;
        }
        catch(HibernateException e)
        {
            throw e;
        }
        finally
        {
            session.close();
        }
    }

    @Override
    public Annee getAnnee(Integer id) {
       Session session = HibernateUtil.getSession();
       try
       {
           session.beginTransaction();
           Query q = session.createQuery("from Annee as a where a.annee=" + id);
           return (Annee) q.uniqueResult();
       }
       finally
       {
           session.close();
       }
    }

    @Override
    public void insert(Annee annee) {

      Session session = HibernateUtil.getSession();
      Transaction tx=null;
      try
      {
          tx = session.beginTransaction();
          session.save(annee);
          tx.commit();         
      }
      catch(RuntimeException e)
      {
          if(tx != null) 
            {
                tx.rollback();
            }
          throw e;
      }
      finally
      {
          session.close();
      }
    }

    @Override
    public void update(Annee annee) {
        Session session = HibernateUtil.getSession();
        Transaction tx=null;
        try
        {
            tx=session.beginTransaction();
            session.update(annee);
            tx.commit();
        }
         catch(RuntimeException e)
         {
           if(tx != null) 
            {
                tx.rollback();
            }
            throw e;
         }
         finally
         {
            session.close();
         }
    }

    @Override
    public void delete(Integer id) {
       Session session = HibernateUtil.getSession();
       Transaction tx = null;
       try
       {
           tx=session.beginTransaction();
           annee = (Annee) session.get(Annee.class,id);
           session.delete(annee);
           tx.commit();
       }
       catch(RuntimeException e)
         {
            if(tx != null) 
            {
                tx.rollback();
            }
            throw e;
         }
         finally
         {
            session.close();
         }
    }


}

HibernateUtil.java 

package dao;

import org.hibernate.Session;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.SessionFactory;

/**
 * Hibernate Utility class with a convenient method to get Session Factory
 * object.
 *
 * @author images
 */
public class HibernateUtil {

    private static final SessionFactory sessionFactory;

    static {
        try {
            // Create the SessionFactory from standard (hibernate.cfg.xml) 
            // config file.
            sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        } catch (Throwable ex) {
            // Log the exception. 
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static Session getSession() {
        return sessionFactory.openSession();
    }
}

Pojo文件

Annee.java 

package net.vo;

public class Annee  implements java.io.Serializable {


     private int annee;

    public Annee() {
    }

    public Annee(int annee) {
       this.annee = annee;
    }

    public int getAnnee() {
        return this.annee;
    }

    public void setAnnee(int annee) {
        this.annee = annee;
    }




}

映射文件：Annee.hbm.xml 

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 13 mai 2014 18:23:22 by Hibernate Tools 3.2.1.GA -->
<hibernate-mapping>
    <class name="net.vo.Annee" table="annee" catalog="base">
        <id name="annee" type="int">
            <column name="annee" />
            <generator class="assigned" />
        </id>
    </class>
</hibernate-mapping>

弹簧 AnneeMetier.java 

package model.services;

import java.util.List;

public interface AnneeMetier {
    public List getAllAnnees();
}

AnneeMetierImpl.java 

package model.services;

import dao.AnneeDao;
import java.util.List;
import net.vo.Annee;

public class AnneeMetierImpl implements AnneeMetier{

    private AnneeDao anneeDao;

    @Override
    public List getAllAnnees() {
            return anneeDao.getAllAnnees();
    }

    public void setAnneeDao(AnneeDao anneeDao) {
        this.anneeDao = anneeDao;
    }

    public AnneeDao getAnneeDao() {
        return anneeDao;
    }

}

JSF AnneeBean.java 

package controller;

import java.util.List;
import model.services.AnneeMetier;
import net.vo.Annee;

public class AnneeBean {

    private AnneeMetier anneeMetier;

    private List<Annee> listeAnnees;

    public List getListeAnnees() {
        listeAnnees = anneeMetier.getAllAnnees();
        return listeAnnees;
    }

    public void setListeAnnees(List listeAnnees) {
        this.listeAnnees = listeAnnees;
    }

    public AnneeMetier getAnneeMetier() {
        return anneeMetier;
    }

    public void setAnneeMetier(AnneeMetier anneeMetier) {
        this.anneeMetier = anneeMetier;
    }

}

的web.xml 

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" 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/web-app_3_0.xsd">
       <listener>
      <listener-class>
         org.springframework.web.context.ContextLoaderListener
      </listener-class>
   </listener>
   <listener>
      <listener-class>
         org.springframework.web.context.request.RequestContextListener
      </listener-class>
   </listener>
    <context-param>
        <param-name>javax.faces.PROJECT_STAGE</param-name>
        <param-value>WEB-INF/applicationContext.xml</param-value>
    </context-param>
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>/faces/*</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>faces/index.xhtml</welcome-file>
    </welcome-file-list>
</web-app>

的applicationContext.xml 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop/spring-aop-3.1.xsd"
       xmlns:context="http://www.springframework.org/schema/context/spring-context-3.1.xsd"
       xmlns:tx="http://www.springframework.org/schema/tx/spring-tx-3.1.xsd"

       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
          http://www.springframework.org/schema/aop/spring-aop-3.1.xsd http://www.springframework.org/schema/aop/spring-aop-3.1.xsd/spring-spring-aop-3.1.xsd-3.1.1.RELEASE.xsd
          http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/context/spring-context-3.1.xsd/spring-spring-context-2.5.xsd-3.1.1.RELEASE.xsd
          http://www.springframework.org/schema/tx/spring-tx-3.1.xsd http://www.springframework.org/schema/tx/spring-tx-3.1.xsd/spring-spring-tx-3.1.xsd-3.1.1.RELEASE.xsd
">
     <bean id="anneeDao" class="dao.AnneeHibernateDao"></bean>
    <bean id="anneeMetier" class="model.services.AnneeMetierImpl">
        <property name="anneeDao" ref="anneeDao"/>  
    </bean>  

</beans>

faces-config.xml中

<?xml version='1.0' encoding='UTF-8'?>

<!-- =========== FULL CONFIGURATION FILE ================================== -->

<faces-config version="2.1"
    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/web-facesconfig_2_1.xsd">

<application>
   <variable-resolver>
      org.springframework.web.jsf.DelegatingVariableResolver
   </variable-resolver>
</application>
 <managed-bean>
      <managed-bean-name>anneeBean</managed-bean-name>
      <managed-bean-class>controller.AnneeBean</managed-bean-class>
      <managed-bean-scope>request</managed-bean-scope>
   </managed-bean> 
</faces-config>

的index.xhtml 

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:p="http://primefaces.org/ui">
    <h:head>
        <title>Facelet Title</title>
    </h:head>
    <h:body>
        <h:dataTable var="annees" value="#{anneeBean.listeAnnees}">
                    <p:column headerText="Annee">
                        <h:outputText value="#{annee.annees}"/>
                    </p:column>
                </h:dataTable>
    </h:body>
</html>

请你帮助我，我会很感激

编辑 这是堆栈跟踪更新

mai 14, 2014 1:14:41 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/testJSF_Spring_Hibernate] threw exception [Erreur lors de linjection de ressources dans le bean géré anneeBean] with root cause
java.lang.NullPointerException
    at model.services.AnneeMetierImpl.getAllAnnees(AnneeMetierImpl.java:17)
    at controller.AnneeBean.init(AnneeBean.java:25)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at com.sun.faces.vendor.WebContainerInjectionProvider.invokeAnnotatedMethod(WebContainerInjectionProvider.java:117)
    at com.sun.faces.vendor.WebContainerInjectionProvider.invokePostConstruct(WebContainerInjectionProvider.java:99)
    at com.sun.faces.mgbean.BeanBuilder.invokePostConstruct(BeanBuilder.java:223)
    at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:105)
    at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
    at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
    at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244)
    at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116)
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
    at com.sun.faces.el.ChainAwareVariableResolver.resolveVariable(ChainAwareVariableResolver.java:107)
    at org.springframework.web.jsf.DelegatingVariableResolver.resolveOriginal(DelegatingVariableResolver.java:123)
    at org.springframework.web.jsf.DelegatingVariableResolver.resolveVariable(DelegatingVariableResolver.java:108)
    at com.sun.faces.el.VariableResolverChainWrapper.getValue(VariableResolverChainWrapper.java:115)
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
    at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:72)
    at org.apache.el.parser.AstValue.getValue(AstValue.java:161)
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:185)
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
    at javax.faces.component.UIData.getValue(UIData.java:731)
    at javax.faces.component.UIData.getDataModel(UIData.java:1798)
    at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484)
    at javax.faces.component.UIData.setRowIndex(UIData.java:473)
    at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
    at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820)
    at javax.faces.component.UIData.encodeBegin(UIData.java:1118)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1754)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:401)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:410)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

编辑2： 这是AnneeBean类

package controller;

import java.util.List;
import javax.annotation.PostConstruct;
import model.services.AnneeMetier;
import model.services.AnneeMetierImpl;
import net.vo.Annee;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope("view")
public class AnneeBean {

    @Autowired
    private AnneeMetier anneeMetier;

    private List<Annee> listeAnnees;

    @PostConstruct
    public void init() {
        anneeMetier = new AnneeMetierImpl();
        listeAnnees = anneeMetier.getAllAnnees();
    }
    public List getListeAnnees() {
        listeAnnees = anneeMetier.getAllAnnees();
        return listeAnnees;
    }

    public void setListeAnnees(List listeAnnees) {
        this.listeAnnees = listeAnnees;
    }

    public AnneeMetier getAnneeMetier() {
        return anneeMetier;
    }

    public void setAnneeMetier(AnneeMetier anneeMetier) {
        this.anneeMetier = anneeMetier;
    }

}

编辑3： 的index.xhtml 

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:p="http://primefaces.org/ui"
      xmlns:f="http://java.sun.com/jsf/core">
    <h:head>
        <title>Facelet Title</title>
    </h:head>
    <h:body>
 <h:form>
     <p:dataTable var="listeAnnees" value="#{anneeBean.listeAnnees}">
                <p:column headerText="Annee">
                    <h:outputText value="#{listeAnnees.annee}"/>
                    </p:column>
            </p:dataTable>        
        </h:form>
    </h:body>
</html>

2 个答案:

答案 0 :(得分：3)

非JSF开发人员的天真解决方案是简单地初始化getter中的变量以解析属性中的null值。这是：

public List getListeAnnees() {
    listeAnnees = getAnneeMetier().getAllAnnees();
    return listeAnnees;
}

public AnneeMetier getAnneeMetier() {
    if (anneeMetier == null) {
        anneeMetier = new AnneeMetierImpl();
    }
    return anneeMetier;
}

但是，如果AnneeMetier#getAllAnnees()从数据库中检索数据，这可能会从服务器产生大量开销。这在此解释：Why JSF calls getters multiple times

要解决此问题，您需要做两件事：

  1. Define the right scope of your bean。
  2. 使用@PostConstruct带注释的方法初始化工作所需的数据。

    3. 这会导致：

    1. 将范围定义为@ViewScoped（在上面的链接中说明）。
    2. 在listeAnnees方法中初始化@PostConstruct。
    3. 从getter / setters中删除任何业务逻辑

      4. 所以代码看起来像这样：

      @ManagedBean
@ViewScoped
public class AnneeBean {
    private AnneeMetier anneeMetier;
    private List<Annee> listeAnnees;

    @PostConstruct
    public void init() {
        anneeMetier = new AnneeMetierImpl();
        listeAnnees = anneeMetier.getAllAnnees();
    }

    public List getListeAnnees() {
        return listeAnnees;
    }

    public void setListeAnnees(List listeAnnees) {
        this.listeAnnees = listeAnnees;
    }

    public AnneeMetier getAnneeMetier() {
        return anneeMetier;
    }

    public void setAnneeMetier(AnneeMetier anneeMetier) {
        this.anneeMetier = anneeMetier;
    }
}

      但是，因为您尝试将JSF与Spring集成，您必须考虑Spring has not yet full support of JSF 2 @ViewScoped annotation。对于这种情况，您需要/需要自己实现它。关于这一点，网上有很多例子，看起来最流行的是来自Cagatay's。通过这种方式，您将能够从双方获得力量。你的bean看起来像这样：

      @Component
@Scope("view")
public class AnneeBean {
    @Autowired
    private AnneeMetier anneeMetier;
    private List<Annee> listeAnnees;

    @PostConstruct
    public void init() {
        listeAnnees = anneeMetier.getAllAnnees();
    }

    public List getListeAnnees() {
        return listeAnnees;
    }

    public void setListeAnnees(List listeAnnees) {
        this.listeAnnees = listeAnnees;
    }
}

      更多信息：

      由于您正在学习Spring，最好的办法是启用组件扫描并使用注释来配置Spring bean。执行以下操作：

      • 删除applicationContext.xml中的所有bean配置。

      • 添加此配置以启用Bean扫描注释：

        <!-- 
    These will enable component scan by annotation configuration
    rather than XML configuration. One per package
-->
<context:component-scan base-package="dao" />
<context:component-scan base-package="model.services" />

        或者，如果所有课程都在一个根包中。

        <!--
    Assuming there's a root package for your packages like this
<context:component-scan base-package="com.myproject.dao" />
<context:component-scan base-package="com.myproject.model.services" />
-->
<context:component-scan base-package="com.myproject" />

      • 开始通过注释配置Spring托管bean：

        @Repository
public class AnneeHibernateDao implements AnneeDao{
    //...
}

@Service
public class AnneeMetierImpl implements AnneeMetier{
    @Autowired
    private AnneeDao anneeDao;
    //...
}

      编译项目并运行它。

答案 1 :(得分：2)

您正在使用getListeAnnees打算调用private object名为anneeMetier的方法，该方法尚未初始化。您通过object方法初始化setAnneeMetier，该方法从未在代码中初始化，因此它是null。您可以通过执行以下操作之一来解决问题：

  1. 您在使用anneeMetier

    之前致电setAnneeMetier初始化getListeAnnees

  2. 您为初始化AnneeBean

    3. 的anneeMetier课程实施构造函数

  3. 您可以将getter（getListeAnnees）修改为如下所示：

    public List getListeAnnees() { if (anneeMetier == null) { return new ArrayList<Annee>(); } listeAnnees = anneeMetier.getAllAnnees(); return listeAnnees; }

    4. 编辑：pL4GU33的评论可能有用，所以我将他的评论的想法添加到答案中：

    public List getListeAnnees() { if (anneeMetier == null) { return Collections.emptyList(); } listeAnnees = anneeMetier.getAllAnnees(); return listeAnnees; }

    他的解决方案与类型无关，所以我赞成他的评论。

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