预览时报如下错误：
java.lang.NullPointerException at com.fr.util.SynchronizedLiveDataModelUtils.getLiveDataModel(Unknown Source) at com.fr.report.core.A.O.__s_name2ResultSet(Unknown Source) at com.fr.report.core.A.N.A(Unknown Source) at com.fr.report.core.A.PA.A(Unknown Source) at com.fr.report.core.A.N.C(Unknown Source) at com.fr.report.core.A.N.A(Unknown Source) at com.fr.report.core.A.N.execute4Expand(Unknown Source) at com.fr.report.core.A.N.B(Unknown Source) at com.fr.report.WorkSheet._execute(Unknown Source) at com.fr.report.WorkSheet.execute(Unknown Source) at com.fr.report.core.A.B.F.G(Unknown Source) at com.fr.report.core.A.B.F.B(Unknown Source) at com.fr.main.impl.WorkBook.execute(Unknown Source) at com.fr.log.LogUtils$1.exe(Unknown Source) at com.fr.log.LogUtils.executeAndLogAndRecord(Unknown Source) at com.fr.log.LogUtils.executeAndLogRecord(Unknown Source) at com.fr.web.cache.ReportCache.getResultWorkBook(Unknown Source) at com.fr.main.impl.WorkBookTemplateDelegate.execute(Unknown Source) at com.fr.web.core.ShowWorkBookPolicy$Policy4Page.show(Unknown Source) at com.fr.web.core.ReportSessionIDInfor.showDirect(Unknown Source) at com.fr.web.core.ReportSessionIDInfor.initBook2Show(Unknown Source) at com.fr.web.core.ReportSessionIDInfor.getWorkBook2Show(Unknown Source) at com.fr.web.core.ReportSessionIDInfor.createPageSetChain(Unknown Source) at com.fr.web.core.ReportSessionIDInfor.getReportPage(Unknown Source) at com.fr.web.core.service.PageService$PageContentReader.getReportPageBySessionIDInfo(Unknown Source) at com.fr.web.core.service.PageService$PageContentReader.readPageContent(Unknown Source) at com.fr.web.core.service.PageService.process(Unknown Source) at com.fr.web.core.ReportDispatcher.dealWithRequest(Unknown Source) at com.fr.web.BaseServlet.doGet(Unknown Source) at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) at javax.servlet.http.HttpServlet.service(HttpServlet.java:723) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879) at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:617) at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1760) at java.lang.Thread.run(Thread.java:722)
