Hibernate + JSF2会话已关闭

Question

在添加新国家时，我在JSF + Hibernate应用程序中获得会话关闭异常。这是供您参考的代码

country.xhtml

<f:metadata>
    <f:event listener="#{country.getPreRequisites}" type="preRenderView"/>
</f:metadata>

上面的代码填充了下面要使用的国家地图。如果我删除f:元数据块，那么我可以添加国家，不会得到会话关闭消息。

<p:selectOneRadio value="#{country.countryId}" id="countryId" columns="4" style="width: 700px" layout="grid">
      <f:selectItems value="#{country.countries}" />
</p:selectOneRadio>

CountryManagedBean.java

@ManagedBean(name = "country")
@ViewScoped
public class CountryManagedBean
{
   public String saveCountry()
   {
      String actionFlag="country";
      FacesMessage message=null;
      try
      {
        int flag=countryDao.saveCountry(this);
        if(flag==1)
        {
            message=new FacesMessage(FacesMessage.SEVERITY_INFO,"Country","Saved Successfully");
            FacesContext.getCurrentInstance().addMessage(null, message);
        }
    }
    catch(Exception e)
    {
        LOG.logp(Level.SEVERE, "CountryManagedBean","saveCountry", "Saving Country Failed", e);
    }
    return actionFlag;
  }
   public void getPreRequisites(ComponentSystemEvent event)
  {
      FacesContext fc = FacesContext.getCurrentInstance();
     if (!fc.isPostback())    //Page Is Called / Rendered
     {
         countryDao.getPreRequisites(this); 
     }
  }
}

CountryDao.java

public class CountryDao
{
   Session session = null;
   Transaction tx=null;
   public void getPreRequisites(CountryManagedBean country)
   {
       try
      {
          tx=session.beginTransaction();
         Criteria cr=session.createCriteria(CountryPojo.class)
        .setProjection(Projections.projectionList()
            .add(Projections.property("countryId"),"countryId")
            .add(Projections.property("countryName"),"countryName")
            .add(Projections.property("countryShortCode"),"countryShortCode")
            )
        .setResultTransformer(Transformers.aliasToBean(CountryPojo.class));
        List<CountryPojo> countryList=cr.list();
        System.out.println("Total Countries Found:"+countryList.size());
        for(CountryPojo pojo:countryList)
        {
            country.getCountries().put(pojo.getCountryName()+" ["+pojo.getCountryShortCode()+"]",pojo.getCountryId());
        }
        CountryPojo p=countryList.get(0);
        System.out.println("%%%%%%%%%%% Country Id:"+p.getCountryId()+"t############# Country Name:"+p.getCountryName());
        tx.commit();
    }
    catch(HibernateException e)
    {
        LOG.logp(Level.SEVERE, "Country Dao", "getPreRequisites","Caught HibernateException while getting pre requisites",e);
        try
        {
            tx.rollback();
        }
        catch(HibernateException ex)
        {
            LOG.logp(Level.SEVERE,"CountryDao","getPreRequisites","Caught HibernateException while rolling back transaction",ex);
        }
    }
    finally
    {
    }
}
public int saveCountry(CountryManagedBean country)
{
    int flag=-1;
    try
    {
        tx=session.beginTransaction();
        CountryPojo countryPojo=new CountryPojo(country.getCountryName(),country.getCountryShortCode(),country.getLastUpdateBy());
        country.setCountryId((Integer)session.save(countryPojo));
        LOG.log(Level.INFO, "Country {0} Saved With Id {1}", new Object[]{country.getCountryName(), country.getCountryId()});
        tx.commit();
    }
    catch(HibernateException e)
    {
        LOG.logp(Level.SEVERE, "Country Dao", "saveCountry","Caught HibernateException while saving country",e);
        try
        {
            tx.rollback();
        }
        catch(HibernateException ex)
        {
            LOG.logp(Level.SEVERE,"CountryDao","saveCountry","Caught HibernateException while rolling back transaction",ex);
        }
    }
    finally
    {
    }
    return flag;
}
public CountryDao()
{
    session = HibernateUtil.getSessionFactory().getCurrentSession();
}
private static final Logger LOG = Logger.getLogger(CountryDao.class.getName());
}

Answer 1

很可能是因为JSF调用getPreRequisites时关闭了JPA/Hibernate会话。你需要将这个添加到你的web.xml中，以保持会话打开，以便视图可以加载你的延迟加载对象。

<filter>
    <filter-name>Spring OpenEntityManagerInViewFilter</filter-name>
    <filter-class>org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>Spring OpenEntityManagerInViewFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>