我正在使用 ContentFlow (http://www.jacksasylum.eu/ContentFlow/index.php) 来显示来自使用 Java、PrimeFaces 和 jsf 的数据库中的图像。我正在使用图像 servlet 来帮助呈现我的图像字节数组。
这在使用我的图像列表进行初始页面加载时是成功的，但是在我的图像列表更改后（使用数据表过滤器的结果），我找不到使用新图像列表重新加载/刷新 ContentFlow 的方法。
此刷新在没有实现 ContentFlow 的情况下成功运行，但它似乎要么在 Javascript 中的幕后做某事破坏了这一点，要么它不能很好地与图像 servlet 一起使用（有时我得到一个 IllegalStateException）。我很难找到任何人来帮助解决这个问题。
这是我的堆栈跟踪...
Error Rendering View[/index.xhtml]: java.lang.IllegalStateException: Cannot create a session after the response has been committed
at org.apache.catalina.connector.Request.doGetSession(Request.java:2636) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.connector.Request.getSession(Request.java:2375) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:841) [jbossweb-7.0.10.Final.jar:]
at com.sun.faces.context.ExternalContextImpl.getSession(ExternalContextImpl.java:155) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at javax.faces.context.ExternalContextWrapper.getSession(ExternalContextWrapper.java:396) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
at com.sun.faces.renderkit.ServerSideStateHelper.writeState(ServerSideStateHelper.java:175) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at com.sun.faces.renderkit.ResponseStateManagerImpl.writeState(ResponseStateManagerImpl.java:122) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at com.sun.faces.application.StateManagerImpl.writeState(StateManagerImpl.java:166) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at com.sun.faces.application.view.WriteBehindStateWriter.flushToWriter(WriteBehindStateWriter.java:225) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:419) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:288) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:288) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.10.Final.jar:]
at org.jboss.weld.servlet.ConversationPropagationFilter.doFilter(ConversationPropagationFilter.java:62) [weld-core-1.1.5.AS71.Final.jar:2012-02-10 15:31]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.10.Final.jar:]
at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.1.0.Final.jar:7.1.0.Final]
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:154) [jboss-as-web-7.1.0.Final.jar:7.1.0.Final]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.10.Final.jar:]
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.10.Final.jar:]
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.10.Final.jar:]
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.10.Final.jar:]
at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_32]
ImgServlet.java
/**
* Servlet implementation class ImgServlet
*/
@WebServlet(name = "ImgServlet", urlPatterns = {"/ImgServlet/*"})
public class ImgServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
@Inject
Screenshot model;
@PersistenceUnit(unitName = "primary")
private EntityManagerFactory emf;
public ImgServlet() {
super();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
PrintWriter writer = response.getWriter();
ServletContext sc = getServletContext();
String classString = "Screenshot";
String idString = request.getParameter("id");
if (classString == null || classString.isEmpty() || idString == null || idString.isEmpty()) {
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
return;
}
Long id = Long.parseLong(idString.trim());
PhotoInterface entry = null;
EntityManager em = null;
try {
em = emf.createEntityManager();
} catch (Throwable e1) {
e1.printStackTrace();
}
try {
entry = em.find(Screenshot.class, id);
} catch (Exception ex) {
//Log.log(ex.getMessage());
}
if (entry == null) {
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
return;
}
ServletOutputStream out = null;
try {
response.reset();
// It works ok without setting any of these...
//response.setContentType(image.getContentType());
//response.setHeader("Content-Length", String.valueOf(image.getLength()));
//response.setHeader("Content-Disposition", "inline; filename=\"" + image.getName() + "\"");
response.setContentType("image/png");
out = response.getOutputStream();
if (entry.getPng() != null && entry.getPng().length != 0) {
out.write(entry.getPng());
getServletContext().log("Found png!!");
}
else
getServletContext().log("png is NULL!!!");
} catch (IOException e) {
getServletContext().log("Error finding png!!!");
} finally {
close(out);
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
private static void close(Closeable resource) {
if (resource != null) {
try {
resource.close();
} catch (IOException e) {
// Do your thing with the exception. Print it, log it or mail it.
}
}
}
}
ContentFlow 制作 ContentFlow 的 Javascript 文件可以在http://www.jacksasylum.eu/ContentFlow/download.php查看没有足够的空间在这里包含它。
获取数据表选择列表后，这段 xhtml 代码将起作用。此外，尝试使用过滤数据表过滤结果列表。ContentFlow div 未在此处实现...
<p:commandButton id="viewDetails" value="View Selected Screenshots" icon="ui-icon-search"
update=":form:imgBlock"/>
<p:outputPanel id="imgBlock" layout="block">
<a4j:repeat var="img" value="#{screenshotListProducer.selectedScreenshots}">
<img src="ImgServlet?id=#{img.id}" title="#{img.time}"/>
</a4j:repeat>
</p:outputPanel>
用 ContentFlow div 封装后，这段 xhtml 代码不起作用。一定是在幕后发生了一些我只是不明白的事情......
<p:commandButton id="viewDetails" value="View Selected Screenshots" icon="ui-icon-search"
update=":form:imgBlock"/>
<p:outputPanel id="imgBlock" layout="block">
<div class="ContentFlow" id="ContentFlow">
<div class="flow">
<a4j:repeat var="img" value="#{screenshotListProducer.selectedScreenshots}">
<div class="item">
<img src="ImgServlet?id=#{img.id}" title="#{img.time}"/>
</div>
</a4j:repeat>
</div>
</div>
</p:outputPanel>