我使用StreamingContent从目前可用的primefaces流式传输图像和pdf。我处理Primefaces StreamedContent
中描述的流媒体public StreamedContent getStreamedImageById() {
FacesContext context = FacesContext.getCurrentInstance();
if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
// So, we're rendering the view. Return a stub StreamedContent so that it will generate right URL.
return new DefaultStreamedContent();
}
else {
// So, browser is requesting the image. Get ID value from actual request param.
String id = context.getExternalContext().getRequestParameterMap().get("id");
Image image = service.find(Long.valueOf(id));
return new DefaultStreamedContent(new ByteArrayInputStream(image.getBytes()));
}
}
现在我用ui在两个地方包含了相应的xhtml：include并用CDI创建了两个独立的辅助bean实例。我用ui：param：
传递了正确的实例<ui:include src="/sections/content/contentViewer.xhtml">
<ui:param name="beanBL" value="#{editPropertyContentBL}" />
</ui:include>
并在xhtml中使用传递的bean（这里是它的一小部分）：
<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://java.sun.com/jsf/core" xmlns:p="http://primefaces.org/ui" xmlns:h="http://java.sun.com/jsf/html"
xmlns:o="http://omnifaces.org/ui" xmlns:pe="http://primefaces.org/ui/extensions">
<h:panelGroup id="contentViewerOuterId"
rendered="#{not beanBL.isSelectedContentMimeTypeStartsWith('text/')}">
<!-- pdf content -->
<pe:documentViewer id="docViewerId" value="#{beanBL.inlineContent}"
rendered="#{beanBL.isSelectedContentMimeTypeStartsWith('application/pdf')}" />
...
通过将bean实例作为ui：param传递，从不执行支持bean流处理代码的else部分。我得到一个NPE（这是完整的堆栈跟踪）：
12:41:19,368 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/App].[Faces Servlet]] (http-/0.0.0.0:9090-6) JBWEB000236: Servlet.service() for servlet Faces Servlet threw exception: java.lang.NullPointerException
at org.primefaces.application.resource.StreamedContentHandler.handle(StreamedContentHandler.java:56) [primefaces-5.1.17.jar:5.1.17]
at org.primefaces.application.resource.PrimeResourceHandler.handleResourceRequest(PrimeResourceHandler.java:84) [primefaces-5.1.17.jar:5.1.17]
at javax.faces.application.ResourceHandlerWrapper.handleResourceRequest(ResourceHandlerWrapper.java:153) [jsf-api-2.2.11.jar:2.2]
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:651) [jsf-api-2.2.11.jar:2.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:295) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:72) [primefaces-5.1.17.jar:5.1.17]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at ip.client.commons.web.xss.filter.XSSFilter.doFilter(XSSFilter.java:53) [ip-filter-xss-4.3.0.jar:4.3.0]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.omnifaces.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:115) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at ip.client.web.filter.commons.AbstractFilter.doFilter(AbstractFilter.java:106) [ip-filter-commons-5.0.0-SNAPSHOT.jar:5.0.0-SNAPSHOT]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.omnifaces.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:115) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.omnifaces.filter.GzipResponseFilter.doFilter(GzipResponseFilter.java:149) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:149) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:169) [jboss-as-web-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:145) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:97) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:102) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:336) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:653) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:920) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_75]
如果我删除ui：param并直接在包含的xhtml中使用cdi bean名称，则首先执行if-part，然后执行else部分并且它可以正常工作。 我不明白。也许有人可以解释一下？
由于 奥利弗