在调用BufferedOutputStream的flush方法时报了如下的错，没明白这是报的什么错：
java.io.IOException: write beyond end of stream
at java.util.zip.DeflaterOutputStream.write(DeflaterOutputStream.java:102)
at java.util.zip.GZIPOutputStream.write(GZIPOutputStream.java:72)
at com.bstek.dorado.core.GZIPEncodeFilter$GZIPServletStream.write(GZIPEncodeFilter.java:130)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
at com.fenet.insurance.mm.invoice.action.InvoiceInfoToXMLAction.invoiceExport(InvoiceInfoToXMLAction.java:115)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.bstek.dorado.view.ViewModelSupport.handleUpdate(ViewModelSupport.java:954)
at com.bstek.dorado.view.rpc.UpdateDataRPCHandler.internalExecute(UpdateDataRPCHandler.java:119)
at com.bstek.dorado.view.rpc.AbstractRPCHandler.execute(AbstractRPCHandler.java:119)
at com.bstek.dorado.view.smartweb.v2.ViewServiceController.doRPC(ViewServiceController.java:457)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.bstek.dorado.action.Controller.doDispatch(Controller.java:220)
at com.bstek.dorado.action.Controller.internalDispatch(Controller.java:174)
at com.bstek.dorado.action.Controller.internalDispatch(Controller.java:138)
at com.bstek.dorado.action.Controller.invokeAction(Controller.java:113)
at com.bstek.dorado.action.ActionHandler.invokeAction(ActionHandler.java:140)
at com.bstek.dorado.action.ActionHandler.invokeAction(ActionHandler.java:130)
at com.bstek.dorado.core.DoradoServlet.doGet(DoradoServlet.java:85)
at com.bstek.dorado.core.DoradoServlet.doPost(DoradoServlet.java:109)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.bstek.dorado.core.FilterHandle.internalDoFilter(FilterHandle.java:362)
at com.bstek.dorado.core.FilterHandle.doAgentRPCFilter(FilterHandle.java:309)
at com.bstek.dorado.core.FilterHandle.doFilter(FilterHandle.java:155)
at com.bstek.dorado.core.DoradoFilter.doFilter(DoradoFilter.java:72)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:96)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:662)
代码也贴出来吧，还请大家帮忙分析下，这个问题出在哪里：
public void invoiceExport(ParameterSet parameters,
ParameterSet outParameters) throws Exception {
String xml = "ddddddddd";
HttpServletResponse response = ContextManager.response;
String fileName = "file.xml";
response.reset();// 必须加，不然保存不了临时文件
response.setContentType("application/x-msdownload");// 设置文件内容格式，防止浏览器自动打开
BufferedOutputStream bos=null;
try {
// 设置文件名编码格式
fileName = java.net.URLEncoder.encode(fileName, "GB2312");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("不支持的编码格式！！！");
}
// 设置下载的文件名
response.addHeader("content-Disposition", "attachment;filename=" + fileName);
try {
// 复制流
bos=new BufferedOutputStream(response.getOutputStream());
bos.write(xml.getBytes());
} catch (FileNotFoundException e) {
e.printStackTrace();
throw new RuntimeException("找不到文件！！！");
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException("写文件错误！！！");
} finally {
bos.flush();
bos.close();
}
}
