selectOneMenu用于与转换器 - java.io.NotSerializableException错误

Question

我有以下JSF形式：

... 
<p:column> 
    <h:outputText value="Image Id:" style="font-weight:bold; padding-right:10px" /> 
</p:column> 
<p:column> 
    <h:outputText value="#{syncCenterBean.selectedCRImageData.imId}" /> 
</p:column> 
</p:row>      
....      
<p:row> 
<p:column> 
    <h:outputText value="Image Type" style="font-weight:bold; padding-right:10px" /> 
</p:column> 
<p:column> 
    <p:selectOneMenu id="imtype" value="#{syncCenterBean.cRImageType}" converter="#{imageTypeConvert}"> 
     <f:selectItem itemLabel="Select One" itemValue="" /> 
     <f:selectItems value="#{syncCenterBean.cRImageTypeList}" var="cRImageType" itemValue="#{cRImageType.imTypeId}" itemLabel="#{cRImageType.imTypeName}" /> 
    </p:selectOneMenu> 
</p:column> 
</p:row> 
... 

所有这些都在当选择了数据表中的行加载的对话框。我有这是两个相关的Hibernate实体如下：

CRImageData

@Entity 
@Table(name = "imageviewer_crimagedata") 
public class CRImageData implements Serializable { 

    private static final long serialVersionUID = 1L; 

    @Id 
    @GeneratedValue 
    @Column(name = "ImId") 
    private Long imId; 

    @Column(name = "ImName") 
    private String imName; 

    @Column(name = "ImTypeId") 
    private Long imTypeId; 

    @Column(name = "ImPatientId") 
    private String imPatientId; 

    @Column(name = "ImStatus") 
    private String imStatus; 

    @Column(name = "imFormat") 
    private String imFormat; 

    @ManyToOne 
    @JoinColumn(name="ImTypeId",insertable=false,updatable=false) 
    private CRImageType cRImageType; 

和CRImageType

@Entity 
@Table(name = "imageviewer_crimagetype") 
public class CRImageType implements Serializable { 

    private static final long serialVersionUID = 1L; 

    @Id 
    @GeneratedValue 
    @Column(name = "ImTypeId") 
    private Long imTypeId; 

    @Column(name = "ImTypeName") 
    private String imTypeName; 

    @Column(name = "ImTypeDescription") 
    private String imTypeDescription; 

    @ManyToMany(cascade = {CascadeType.ALL}) 
    @JoinTable(name="imageviewer_imtype_variable", 
    joinColumns={@JoinColumn(name="ImTypeId")}, 
    inverseJoinColumns={@JoinColumn(name="VarId")}) 
    private Set<CRVariable> crvariables = new HashSet<CRVariable>(); 

    @OneToMany(mappedBy="cRImageType") 
    private Set<CRImageData> cRImageData; 

我使用的selectOneMenu用于下列转换器：

@ViewScoped 
@ManagedBean(name = "imageTypeConvert") 
@FacesConverter(forClass=CRImageType.class,value="imageTypeConvert") 
public class ImageTypeConvert implements Converter { 

    @ManagedProperty(value="#{syncCenterBean}") 
    private SyncCenterBean syncCenterBean; 
    FacesContext context = FacesContext.getCurrentInstance(); 
    SyncCenterBean mybean = (SyncCenterBean) context.getExternalContext().getSessionMap().get("syncCenterBean"); 

    @Override 
    public Object getAsObject(FacesContext context, UIComponent component, String value{ 
     Long imTypeId = Long.parseLong(value.trim()); 
     List<CRImageType> cRImageTypeList = mybean.getcRImageTypeList(); 
     for (CRImageType cRImageType:cRImageTypeList) { 
      if(cRImageType.getImTypeId().compareTo(imTypeId)==0){ 
      return cRImageType; 
     } 
     } 
     return null;  
    } 

    @Override 
    public String getAsString(FacesContext context, UIComponent component, Object value) { 
     System.out.println("!!!!!! (2) Into getAsString"); 
     return Long.toString(((CRImageType) value).getImTypeId()); 
    } 

    public SyncCenterBean getSyncCenterBean() { 
     return syncCenterBean; 
    } 

    public void setSyncCenterBean(SyncCenterBean syncCenterBean) { 
     this.syncCenterBean = syncCenterBean; 
    } 

} 

最后我的BackBean：

@ManagedBean(name = "syncCenterBean") 
@ViewScoped 
public class SyncCenterBean implements Serializable { 
    @PostConstruct 
    public void init(){ 
      cRImageTypeList = getImageTypesDB(); 
      cRImageType = new CRImageType();  

      cRImageDataList = populateImageOnlyToDataWarehouseList(getImageDataSOAP()); 

      cRImageDataListLocal = getImageDataDB(); 
    } 
    ... 

但是当我尝试加载datatabe我得到以下错误：

javax.portlet.faces.BridgeException: javax.faces.FacesException:   com.forth.actions.ImageTypeConvert 
at com.liferay.faces.bridge.BridgePhaseRenderImpl.execute(BridgePhaseRenderImpl.java:98) 
at com.liferay.faces.bridge.BridgeImpl.doFacesRequest(BridgeImpl.java:99) 
... 
Caused by: java.io.NotSerializableException: com.forth.actions.ImageTypeConvert 
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1156) 
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326) 
at java.util.HashMap.writeObject(HashMap.java:1001) 

任何想法我已经做错了吗？

Answer 1

视图范围化bean必须是可序列化的，因为它们存储在HTTP会话中，而HTTP会话又可以以序列化形式存储在磁盘文件系统中，而不是作为内存中的常规Java对象引用存储，或通过网络传输以共享服务器群集中的会话。

要么使ImageTypeConvert请求作用域bean，而不是一个视图范围的bean，所以它不需要被序列化：

@RequestScoped 
@ManagedBean 
public class ImageTypeConvert implements Converter { 

或者让它实现串行：

@ViewScoped 
@ManagedBean 
public class ImageTypeConvert implements Converter, Serializable { 

顺便提一下，你已经遇到了严重的设计问题：永远不要将FacesContext作为类的实例变量。这不是线程安全的。将这些context和mybean声明移到方法块内部。

另请注意，我删除了@FacesConverter注释，因为如果您通过#{imageTypeConvert}将它用作受管bean，它仍然不会被使用。另外请注意，我基本上重复了默认值，因此我删除了托管bean的name。