为什么view中没有faces-config.xml范围？如果我不使用faces-config.xml，我将如何设置bean来查看范围？
我使用了以下bean文件：
@ManagedBean
@ViewScoped
public class StatusBean2 implements Serializable {
/**
*
*/
private static final long serialVersionUID = -7528998562821856315L;
private EntityManager em;
public StatusBean2() {
EntityManagerFactory emf = Persistence
.createEntityManagerFactory("FreeBird");
em = emf.createEntityManager();
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) context.getExternalContext()
.getSession(true);
int toIndex = 5;
session.setAttribute("toIndex", toIndex);
}
public List<Status> getStatusList() {
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) context.getExternalContext()
.getSession(true);
User user = (User) session.getAttribute("userdet");
Query query = em.createQuery("SELECT s FROM Status s WHERE s.email='"
+ user.getEmail() + "' ORDER BY s.timeMillis desc",
Status.class);
List<Status> results = query.getResultList();
Query query1 = em.createQuery("SELECT f FROM Friend f WHERE f.email='"
+ user.getEmail() + "'", Friend.class);
List<Friend> results1 = query1.getResultList();
Iterator<Friend> it = results1.listIterator();
while (it.hasNext()) {
String email = it.next().getFriendEmail();
Query query2 = em.createQuery(
"SELECT s FROM Status s WHERE s.email='" + email
+ "' ORDER BY s.timeMillis desc", Status.class);
List<Status> results2 = query2.getResultList();
results.addAll(results2);
}
Collections.sort(results);
int toIndex = (int) session.getAttribute("toIndex");
List<Status> subList = results.subList(0, toIndex);
return subList;
}
}
我在使用注释时遇到的例外情况如下：
Apr 16, 2013 8:41:23 PM com.sun.faces.application.view.FaceletViewHandlingStrategy handleRenderException
SEVERE: Error Rendering View[/Home.xhtml]
java.io.NotSerializableException: com.bean.StatusBean2
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at java.util.HashMap.writeObject(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeArray(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at java.util.HashMap.writeObject(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at com.sun.faces.renderkit.ClientSideStateHelper.doWriteState(ClientSideStateHelper.java:293)
at com.sun.faces.renderkit.ClientSideStateHelper.writeState(ClientSideStateHelper.java:167)
at com.sun.faces.renderkit.ResponseStateManagerImpl.writeState(ResponseStateManagerImpl.java:119)
at com.sun.faces.application.StateManagerImpl.writeState(StateManagerImpl.java:155)
at com.sun.faces.application.view.WriteBehindStateWriter.flushToWriter(WriteBehindStateWriter.java:221)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:406)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:127)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:117)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:135)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:309)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Apr 16, 2013 8:41:23 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/FreeBird_New2] threw exception
java.io.NotSerializableException: com.bean.StatusBean2
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at java.util.HashMap.writeObject(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeArray(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at java.util.HashMap.writeObject(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at com.sun.faces.renderkit.ClientSideStateHelper.doWriteState(ClientSideStateHelper.java:293)
at com.sun.faces.renderkit.ClientSideStateHelper.writeState(ClientSideStateHelper.java:167)
at com.sun.faces.renderkit.ResponseStateManagerImpl.writeState(ResponseStateManagerImpl.java:119)
at com.sun.faces.application.StateManagerImpl.writeState(StateManagerImpl.java:155)
at com.sun.faces.application.view.WriteBehindStateWriter.flushToWriter(WriteBehindStateWriter.java:221)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:406)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:127)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:117)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:135)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:309)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
答案 0 :(得分：4)
在托管bean上使用@ViewScoped注释：
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
@ManagedBean
@ViewScoped
public class AViewScopedBean {
//managed bean contents...
}
如果您不喜欢注释配置（非常奇怪），您可以在faces-config.xml上设置视图范围
<managed-bean>
<managed-bean-name>aViewScopedBean<managed-bean-name>
<managed-bean-class>some.package.AViewScopedBean</managed-bean-class>
<managed-bean-scope>view</managed-bean-scope>
</managed-bean>
请注意，此仅适用于JSF 2.检查您的 faces-config 文件是否配置为处理JSF 2.x版本：
<!-- relevant part of faces-config.xml file for this Q/A -->
<faces-config ... version="2.1">
根据您的问题更新进行修改：
错误信息非常简单：
java.io.NotSerializableException：com.bean.StatusBean2
这意味着您的com.bean.StatusBean2还必须实现Serializable界面。来自java.io.Serializable文档：
遍历图形时，可能会遇到不支持Serializable接口的对象。在这种情况下，将抛出
NotSerializableException并将标识非可序列化对象的类。 （这是你得到的错误）
您可以在此处了解有关Java序列化的更多信息：Java Serialization
从你的问题：是否有必要实现可序列化？，BalusC已经发布了一个很好的答案/解释：JSF backing bean should be serializable?
答案 1 :(得分：2)
检查xsd中列出的faces-config.xml（例如：http://java.sun.com/xml/ns/javaee/web-facesconfig_2_0.xsd）应该会显示view范围是允许的托管bean范围：
<xsd:complexType name="faces-config-managed-bean-scopeOrNoneType">
<xsd:annotation>
<xsd:documentation>
<![CDATA[[
Defines the legal values for the <managed-bean-scope>
element's body content, which includes all of the scopes
normally used in a web application, plus the "none" value
indicating that a created bean should not be stored into
any scope. Alternatively, an EL expression may be used
as the value of this element. The result of evaluating this
expression must by of type java.util.Map.
]]>
</xsd:documentation>
</xsd:annotation>
<xsd:simpleContent>
<xsd:restriction base="javaee:string">
<xsd:pattern value="view|request|session|application|none|#\{.*\}"/>
</xsd:restriction>
</xsd:simpleContent>
</xsd:complexType>
假设jsf 2.0或更高版本
这不是一个新的答案本身，只是另一种了解自己允许的方式
---------------编辑----------------
检查this article：
请注意，bean需要实现Serializable 存储在视图中，视图又存储在会话中。一些 servletcontainer配置将在磁盘上存储会话 而不是在记忆中。配置后，这也是必需的 JSF查看状态保存方法到客户端而不是（默认）服务器。
解释视图范围需要Serializable的原因。