Servlet下载文件

java中下载文件最好用servlet，我在用普通的类实现下载功能时提示getOutputStream has already been commit 的error，查了好多资料都没有解决，（有的说response要reset，有的说jsp页面中不能换行等等，我试过后都不行）用servlet来做则不会有这个问题，源代码如下：

 public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String fileName = (String) request.getParameter("fileName");

        String path = "/dept/hr/files/training/" + fileName;

        String realPath = this.getServletContext().getRealPath(path);

        File f = new File(realPath);

        if (!f.exists()) {

            response.sendError(404, "File not found!");

            return;

        }

       fileName = new String(fileName.getBytes("GB2312"), "ISO8859_1"); //处理文件中含中文的问题,不是万能的

        boolean isOnLine = false;

        response.reset(); //非常重要

        if (isOnLine) { //在线打开方式

            URL u = new URL("file:///" + realPath);

            response.setContentType(u.openConnection().getContentType());

            response.setHeader("Content-Disposition",

                               "inline; filename=" + f.getName());

        } else { //纯下载方式

            response.setContentType("application/x-msdownload");

            response.setHeader("Content-Disposition",

                               "attachment; filename=" + fileName);

        }

        byte[] buf = new byte[1024];

        int len = 0;

        BufferedInputStream br = null;

        OutputStream out = null;

        try {

            br = new BufferedInputStream(new FileInputStream(f));

            out = response.getOutputStream();

            while ((len = br.read(buf)) > 0) {

                out.write(buf, 0, len);

            }

            out.flush();

        } catch (Exception e) {

            //e.printStackTrace();

        } finally {

            if (br != null) {

                br.close();

                br = null;

            }

            if (out != null) {

                out.close();

                out = null;

            }

        }

    }

本源代码是基于axman的版本，根据实际需要稍微改了改，我用的是weblogic，当下载.xls等文件时如果用户选择取消则有时报Connection reset by peer:socket write error,其他类型如.doc文件则不会出错，tomcat下不知道有没有这个问题，网上查了半天不知所以然，但有一点可以肯定，就是它并不影响程序的正常运行，所以我把错误输出语句注释掉了。