File upload 数据表中的Primefaces文件上载

我试图在Datatable中使用Primefaces fileupload，但当我得到多个fileupload时，我得到以下错误

java.lang.NullPointerException
    at org.primefaces.component.fileupload.FileUploadRenderer.decodeSimple(FileUploadRenderer.java:56)
    at org.primefaces.component.fileupload.FileUploadRenderer.decode(FileUploadRenderer.java:47)
    at javax.faces.component.UIComponentBase.decode(UIComponentBase.java:787)
    at javax.faces.component.UIInput.decode(UIInput.java:757)
    at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1181)
    at javax.faces.component.UIInput.processDecodes(UIInput.java:662)
    at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
    at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
    at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
    at org.primefaces.component.api.UIData.process(UIData.java:309)
    at org.primefaces.component.api.UIData.processChildren(UIData.java:297)
    at org.primefaces.component.api.UIData.processPhase(UIData.java:261)
    at org.primefaces.component.api.UIData.processDecodes(UIData.java:227)
    at javax.faces.component.UIForm.processDecodes(UIForm.java:225)
    at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
    at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
    at javax.faces.component.UIViewRoot.processDecodes(UIViewRoot.java:933)
    at com.sun.faces.lifecycle.ApplyRequestValuesPhase.execute(ApplyRequestValuesPhase.java:78)
    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:593)
    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:77)
    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:222)
    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:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
    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:1004)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

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我也得到了非常单文件上传相同的错误。