PrimeFaces fileDownload不起作用 [英] PrimeFaces fileDownload does not work
本文介绍了PrimeFaces fileDownload不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我无法获得主要空间< p：filedownload 的工作。虽然我使用自定义下载bean成功下载文件。看起来像issu是相关的原始文件下载ActionListener，但我看不到如何。有人有线索吗？谢谢。
I can't get the primeFaces <p:filedownload work. While I succeed in downloading the file using a custom download bean. Seems like the issu is related to the primefaces file download ActionListener but I don't see how. Does anyone have a clue? Thanks.
这是我的豆：
@ManagedBean(name="fileDownloadBean")
@SessionScoped
public class FileDownloadBean implements Serializable {
private StreamedContent file;
public StreamedContent getFile() {
return file;
}
public void setFile(StreamedContent file) {
this.file = file;
}
/** Creates a new instance of FileDownloadBean */
public FileDownloadBean() {
InputStream stream = this.getClass().getResourceAsStream("sessionlog.csv");
file = new DefaultStreamedContent(stream, "application/csv", "sessionlog.csv");
}
}
这里是我的视图代码：
and here is my view code:
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.prime.com.tr/ui"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:o="http://openfaces.org/"
template="./../template.xhtml">
<ui:define name="title">
#{bundle.Log}
</ui:define>
<ui:define name="body">
<h:form>
<p:separator style="height: 10px;margin-bottom: 10px;margin-top: 0px;"/>
<p:commandButton value="#{bundle.Log}" image="ui-icon ui-icon-link" ajax="false" disabled="false">
<p:fileDownload value="#{fileDownloadBean.file}" />
</p:commandButton>
</ui:composition>
我收到一个500错误：NullPointerException：
I get a 500 error: NullPointerException :
HTTP Status 500 -
type Exception report
message
descriptionThe server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException
root cause
java.lang.NullPointerException
note The full stack traces of the exception and its root causes are available in the GlassFish Server Open Source Edition 3.1 logs.
GlassFish Server Open Source Edition 3.1
日志：
WARNING: StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
at org.primefaces.component.filedownload.FileDownloadActionListener.processAction(FileDownloadActionListener.java:59)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:769)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:409)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1534)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:326)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:227)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:170)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:822)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:719)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1013)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:662)
推荐答案
InputStream stream = this.getClass().getResourceAsStream("sessionlog.csv");
您已经找到CSV文件的方式期望它是在相同的软件包当中， FileDownloadBean 。
The way as you have located the CSV file expects it to be in the same package as the current class, the FileDownloadBean.
如果是实际上位于包根目录，那么你应该使用：
If it is actually located in the package root, then you should rather be using:
InputStream stream = this.getClass().getResourceAsStream("/sessionlog.csv");
或者如果它实际上位于不同的包中，例如 com。例如，那么你应该使用：
Or if it is actually located in a different package, for example com.example, then you should rather be using:
InputStream stream = this.getClass().getResourceAsStream("/com/example/sessionlog.csv");
或者如果它实际上位于公共Web内容的根目录（那里有$ code> / WEB-INF 文件夹也是所有其他网络文件之一），那么你应该使用：
Or if it is actually located in the root of the public webcontent (there where the /WEB-INF folder also is, among all other web files), then you should rather be using:
InputStream stream = externalContext.getResourceAsStream("/sessionlog.csv");
（通过这种方式，对于WAR类而不是 this.getClass（））
这篇关于PrimeFaces fileDownload不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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