我用以下方法实现资源下载功能：
首先是一个客户端JSP页面，显示可下载的资源列表，当用户点击某个资源是，传递一个唯一的资源编号到Action，在数据库中读取该资源的url，然后下载次数+1，然后把url放到一个request里面，再跳到一个JSP页面：
- HTML code
<%@ page language="java" pageEncoding="GB18030"%><jsp:directive.page import="java.net.URLEncoder"/><% request.setCharacterEncoding("GB18030"); String srcURL = String.valueOf(request.getAttribute("srcURL"));//资源路径 response.setContentType("application/x-download"); String url = "/upload/doc/"+srcURL; String fileName = srcURL; fileName = URLEncoder.encode(fileName, "UTF-8"); response.addHeader("Content-Disposition", "attachment;filename=" + fileName); RequestDispatcher rd = application.getRequestDispatcher(url); rd.forward(request, response); response.flushBuffer(); out.clear(); out.clearBuffer(); out = pageContext.pushBody();%>这时候，可以下载资源了，但是我发现点击某些资源，弹出保存框，并且取消保存的时候，控制台输出如下错误：
- Java code
2009-8-26 22:06:58 org.apache.catalina.core.ApplicationDispatcher invoke严重: Servlet.service() for servlet jsp threw exceptionjava.net.SocketException: Connection reset by peer: socket write error at java.net.SocketOutputStream.socketWrite0(Native Method) at java.net.SocketOutputStream.socketWrite(Unknown Source) at java.net.SocketOutputStream.write(Unknown Source) at org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:750) at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:432) at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:347) at org.apache.coyote.http11.InternalOutputBuffer$OutputStreamOutputBuffer.doWrite(InternalOutputBuffer.java:773) at org.apache.coyote.http11.filters.IdentityOutputFilter.doWrite(IdentityOutputFilter.java:118) at org.apache.coyote.http11.InternalOutputBuffer.doWrite(InternalOutputBuffer.java:583) at org.apache.coyote.Response.doWrite(Response.java:560) at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:361) at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:432) at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:347) at org.apache.catalina.connector.OutputBuffer.writeBytes(OutputBuffer.java:392) at org.apache.catalina.connector.OutputBuffer.write(OutputBuffer.java:381) at org.apache.catalina.connector.CoyoteOutputStream.write(CoyoteOutputStream.java:89) at org.apache.catalina.servlets.DefaultServlet.copyRange(DefaultServlet.java:2083) at org.apache.catalina.servlets.DefaultServlet.copy(DefaultServlet.java:1796) at org.apache.catalina.servlets.DefaultServlet.serveResource(DefaultServlet.java:874) at org.apache.catalina.servlets.DefaultServlet.doGet(DefaultServlet.java:376) at javax.servlet.http.HttpServlet.service(HttpServlet.java:627) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:679) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:461) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:399) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301) at org.apache.jsp.mainViews.downloadAction_jsp._jspService(downloadAction_jsp.java:56) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:679) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:461) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:399) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301) at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1063) at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:386) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:229) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414) at javax.servlet.http.HttpServlet.service(HttpServlet.java:627) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875) at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528) at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689) at java.lang.Thread.run(Unknown Source)2009-8-26 22:06:58 org.apache.catalina.core.StandardWrapperValve invoke