〔Java Web开发典型模块大全〕第十四章报表打印模块. 单击“编译报表”超链接，.再单击“执行”按钮出现下列错误,请问如何解决
message 
description The server encountered an internal error () that prevented it from fulfilling this request.
exception 
org.apache.jasper.JasperException: An exception occurred processing JSP page /jsp/compile.jsp at line 17

14:  application.getRealPath("/reports/")
15:  );
16: 
17:  JasperCompileManager.compileReportToFile(application.getRealPath("/reports/fuheReport.jrxml"),application.getRealPath("/reports/fuheReport.jasper"));
18:  JasperCompileManager.compileReportToFile(application.getRealPath("/reports/subReport.jrxml"),application.getRealPath("/reports/subReport.jasper"));
19:  JasperCompileManager.compileReportToFile(application.getRealPath("/reports/fenlan2.jrxml"),application.getRealPath("/reports/fenlan2.jasper"));
20: %>


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause 
java.lang.NullPointerException
org.apache.commons.digester.Digester.getXMLReader(Digester.java:891)
org.apache.commons.digester.Digester.parse(Digester.java:1572)
net.sf.jasperreports.engine.xml.JRXmlLoader.loadXML(JRXmlLoader.java:239)
net.sf.jasperreports.engine.xml.JRXmlLoader.loadXML(JRXmlLoader.java:226)
net.sf.jasperreports.engine.xml.JRXmlLoader.load(JRXmlLoader.java:214)
net.sf.jasperreports.engine.xml.JRXmlLoader.load(JRXmlLoader.java:168)
net.sf.jasperreports.engine.xml.JRXmlLoader.load(JRXmlLoader.java:152)
net.sf.jasperreports.engine.JasperCompileManager.compileReportToFile(JasperCompileManager.java:108)
org.apache.jsp.jsp.compile_jsp._jspService(compile_jsp.java:71)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.