延遲加載不@服務類工作

Question

我使用休眠3.5.1決賽，與春天3.0.5.RELEASE ，我使用下面的配置的OpenSessionInViewFilter：

<filter> 
    <filter-name>hibernateFilter</filter-name> 
    <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class> 
    <init-param> 
     <param-name>sessionFactoryBeanName</param-name> 
     <param-value>sessionFactory</param-value> 
    </init-param> 
    </filter> 
    <filter-mapping> 
    <filter-name>hibernateFilter</filter-name> 
    <url-pattern>/*</url-pattern> 
    <dispatcher>FORWARD</dispatcher> 
    <dispatcher>REQUEST</dispatcher> 
    <dispatcher>ERROR</dispatcher> 
    </filter-mapping> 

假設我有以下實體：

@SuppressWarnings("serial") 
@Entity 
@Table(name = "adpage", catalog = "mydb") 
public class Adpage implements java.io.Serializable { 

    @Id 
    @Column(name = "pkid", nullable = false, length = 50) 
    @GeneratedValue(strategy = GenerationType.IDENTITY) 
    @Basic(fetch = FetchType.EAGER) 
    private long pageId; 

    @ManyToOne(fetch = FetchType.LAZY) 
    @JoinColumn(name = "audio_file_id", unique = true, nullable = true) 
    private AudioFile audioFile ; 

} 

和我支持bean如下：

@Component("myBean") 
@Scope("view") 
public class MyBean { 

    @Autowired 
    private AdPageDao adPageDao; 

    @Autowired 
    private AdPageService adPageService; 

    public void preRender() { 
       adPageObj = adPageDao.getAdPageByID(adPageId); 
    } 

    public void deleteAdPage(Adpage adPage) { 
     adPageService.deleteAdPage(adPage); 
    } 



} 

我服務如下：

@Service 
public class AdPageService { 

    @Autowired 
    private AudioFileDao audioFileDao; 

    public void deleteAdPage(Adpage adPage) { 


     if (adPage.getAudioFile() != null) { 
      log.debug("deleting audio file: " 
        + adPage.getAudioFile().getName() + " for adpage: " // exception here 
        + adPage.getName()); 
      audioFileDao.deleteAudioFile(adPage.getAudiofileref()); 
      GeneralUtils.deleteFilePhysically(adPage.getAudioFile() 
        .getName(); 
     } 

    } 


} 

我XHTML頁面如下：

<f:event type="preRenderView" listener="#{myBean.preRender}" /> 
<ice:panelGrid columns="2"> 

       <ice:outputLabel id="fileName">File Name:</ice:outputLabel> 
       <ice:outputText value="#{myBean.adPageObj.audioFile.originalName}"></ice:outputText> 

       <ice:outputLabel id="fileLength">File Length:</ice:outputLabel> 
       <ice:outputText value="#{myBean.adPageObj.audioFile.length}"></ice:outputText> 

       <ice:outputLabel id="fileDesc">Description:</ice:outputLabel> 
       <ice:outputText value="#{myBean.adPageObj.audioFile.description}"></ice:outputText> 

       </ice:panelGrid> 

在懶惰加載的xhtml頁面沒有問題，文件數據是正常顯示，但在刪除文件時，我收到以下錯誤在刪除服務方法：AdPageService.deleteAdPage

Could not initialize proxy - no Session 

請告知如何解決這個錯誤。

Answer 1

如果AdPage對象已加載到您的視圖中（由於OpenSessionInViewFilter而導致之前的Hibernate會話），則延遲加載不起作用，因爲實體現在是「分離」的。

爲了解決延遲加載問題，你可以這樣做：

1. reattach the entity當前的Hibernate會話
2. 做一個預先抓取之前，確保所有屬性都加載
3. 重裝實體通過它的id （pageId這裏）

我會去選項3（通過它的ID重新加載）來獲得一個新的實體（這可能已經改變，同時顯示/提交表格）。