关于输出流问题，在线等！

这是我的action方法
public ActionForward downFile(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
String mailId = request.getParameter("mailId");
MailDoc doc = mailService.getMailDoc(mailId);
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
OutputStream fos = null;
InputStream fis = null; String filepath = request.getSession().getServletContext().getRealPath("/")+ "SNRCM/otherfiles/mail/"+mailId+doc.getDocSuffix();
System.out.println("文件路径" + filepath);
File uploadFile = new File(filepath);
fis = new FileInputStream(uploadFile);
bis = new BufferedInputStream(fis);
fos = response.getOutputStream();
bos = new BufferedOutputStream(fos);

response.setHeader("Content-disposition", "attachment;filename="
+ URLEncoder.encode(doc.getDocName(), "utf-8"));
int bytesRead = 0;
byte[] buffer = new byte[8192];
while ((bytesRead = bis.read(buffer, 0, 8192)) != -1) {
bos.write(buffer, 0, bytesRead);

}
bos.flush();
fis.close();
bis.close();
fos.close();
bos.close();
return null;
}
这是异常
ExceptionHandler - ExceptionHandler caught this exception:
 ClientAbortException:  java.net.SocketException: Connection reset by peer: socket write error
at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:358)
at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:325)
at org.apache.catalina.connector.OutputBuffer.writeBytes(OutputBuffer.java:381)
at org.apache.catalina.connector.OutputBuffer.write(OutputBuffer.java:370)
at org.apache.catalina.connector.CoyoteOutputStream.write(CoyoteOutputStream.java:89)
at java.io.BufferedOutputStream.write(BufferedOutputStream.java:105)
at com.sunnysoft.snrcm.mail.struts.action.MailAction.downFile(MailAction.java:257)
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 org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:270)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187)
at org.springframework.web.struts.DelegatingActionProxy.execute(DelegatingActionProxy.java:110)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at com.sunnysoft.snrcm.com.struts.action.ActionServlertToGBK.process(ActionServlertToGBK.java:17)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.sunnysoft.snrcm.framework.filter.EncodingFilter.doFilter(EncodingFilter.java:46)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
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.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.net.SocketException: Connection reset by peer: socket write error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
at org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:740)
at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:434)
at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:349)
at org.apache.coyote.http11.InternalOutputBuffer$OutputStreamOutputBuffer.doWrite(InternalOutputBuffer.java:764)
at org.apache.coyote.http11.filters.ChunkedOutputFilter.doWrite(ChunkedOutputFilter.java:126)
at org.apache.coyote.http11.InternalOutputBuffer.doWrite(InternalOutputBuffer.java:573)
at org.apache.coyote.Response.doWrite(Response.java:560)
at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:353)
... 35 more
RequestProcessor - processForwardConfig(ForwardConfig[name=null,path=/SNRCM/common/error.jsp,redirect=false,contextRelative=false,module=null])
 2010-8-24 1:18:36 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.IllegalStateException: Cannot forward after response has been committed
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:312)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1085)
at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:398)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:241)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at com.sunnysoft.snrcm.com.struts.action.ActionServlertToGBK.process(ActionServlertToGBK.java:17)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.sunnysoft.snrcm.framework.filter.EncodingFilter.doFilter(EncodingFilter.java:46)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
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.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Thread.java:619)