我在用servlet寫了一個下載功能，先把文件打包成RAR，然后通過SERVLET下載，但遇到了無法下載的問題。代碼是：public void exportDown(HttpRequest request, HttpServletResponse response,              User user) throws ServletException, IOException {          ExportLogApp app = new ExportLogApp(                  "from Test1 where 1=1 and id <1001 ");          int i = app.exportDownRAR(user.getId(), null, null);          if (i == app.LOG) {              user.addLog("數(shù)據(jù)交換", "導(dǎo)出下載數(shù)據(jù)", "用戶[" + user.getId() + "]導(dǎo)出數(shù)據(jù)成功！");              String filePath = app.getRARpath_save() + File.separator                      + app.getRARname_save() + ".rar";              filePath = filePath.replaceAll("/", "\\\\");              // 定義輸出類型(下載)              response.setContentType("application/force-download");              // 定義輸出文件頭              response.setHeader("Content-Disposition", "attachment;filename=\""                      + app.getRARname_save() + ".rar\"");                File file = new File(filePath);              int len = (int) file.length();                byte[] buf = new byte[len];              FileInputStream fis = new FileInputStream(file);              OutputStream out = response.getOutputStream();              len = fis.read(buf);              out.write(buf, 0, len);              out.flush();              out.close();              fis.close();              file.delete();            } else if (i == app.LOG_ERROR) {              user.addLog("數(shù)據(jù)交換", "導(dǎo)出下載數(shù)據(jù)", "用戶[" + user.getId() + "]導(dǎo)出數(shù)據(jù)失敗！");              PrintWriter out = response.getWriter();              out.println("<script language='javascript'>");              out.println("alert('導(dǎo)出數(shù)據(jù)出錯，請聯(lián)系管理員！');");              out.println("window.location.href='../expert/expert_account.jsp';");              out.println("window.close()");              out.println("</script>");          } else if (i == app.NO_DATA) {            }      }   請幫我解答下，為什么會這樣，我測試用的瀏覽器是IE7.