我servlet中没有进行页面跳转操作啊

有框架了吗？没用的话，你在servlet里面要处理响应啊

顶顶顶，有谁能解答一下吗

可以直接用httpresponse输出流

jsp也就是一个servlet

protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String id = req.getParameter("id");
String savepath;
ResourceService rService = new ResourceService();
try {
Resource resource = rService.findById(id);
savepath = resource.getSavepath();
String filename=resource.getRealname();
File file = new File(savepath);
if (file.exists()) {
resp.setCharacterEncoding("utf-8");
resp.setHeader("content-disposition", "attchment;filename="
+ filename);
FileInputStream fStream = new FileInputStream(file);
OutputStream fOutputStream = resp.getOutputStream();
IOUtils.copy(fStream, fOutputStream);
fOutputStream.close();
fStream.close();
}
else{
req.setAttribute("msg", "文件不存在");
req.getRequestDispatcher("/showresource.jsp").forward(req, resp);
}
} catch (SQLException e) {
e.printStackTrace();
req.setAttribute("msg", "文件下载失败");
req.getRequestDispatcher("/showresource.jsp").forward(req, resp);
}