java 文件下载（含POI）

// 按组联系导出联系人(把文件先通过poi上传到服务器的目录，在去服务器下载到（另存为的目录）)

 public ActionForward exportByGroup(ActionMapping
mapping, ActionForm form,

   HttpServletRequest
request, HttpServletResponse response)

   throws
Exception {

  response.setCharacterEncoding("UTF-8");

  request.setCharacterEncoding("UTF-8");

  // Excel 文件存放在服务器的相对路径下

  String outputFile =
request.getRealPath("/tmp");

  File folder = new
File(outputFile);

  folder.mkdirs();

  System.out.println("导出时服务器端文件保存的位置为："
+ outputFile);

  

  

  HttpSession session =
request.getSession();

  LinkmanForm linkmanForm =
(LinkmanForm) form;

  Page page =
linkmanForm.getPage();

  List<Linkman>
list = null;

  String file = "";

  try {

   Integer pid =
(Integer) session.getAttribute("groupid");

   String
groupid = pid.toString();

   list =
null;

   if (pid == 0
|| "".equals(groupid)) {

    page
= manService.queryNull(page);

    list=manService.queryNullAll();

   } else
{

    page
= manService.queryByGroup(groupid,page);

    list=manService.queryByGroupAll(groupid);

   }

   file =
LinkMan_excel.getPayExcel(list, outputFile);

  } catch (Exception e) {

   e.printStackTrace();

  }

  file =
file.replace("\\", "/");

  //转码，重点（防止文件名乱码）

  String fileName =
URLEncoder.encode(file.substring(file

    .lastIndexOf("/")
+ 1, file.length()), "UTF-8");

  ServletOutputStream sos =
response.getOutputStream();

  FileInputStream fis =
null;

  try {

   //重点

   response.reset();

   response.setHeader("content-disposition",
"attachment;filename="

     +
fileName);

   //
response.setContentType("application/vnd.ms-excel");//此项内容随文件类型而异

   response.setContentType("APPLICATION/OCTET-STREAM");

   byte temp[] =
new byte[1000];

   fis = new
FileInputStream(file);

   int n =
0;

   while ((n =
fis.read(temp)) != -1) {

    sos.write(temp,
0, n);

   }

  } catch (Exception e) {

   e.printStackTrace();

  }
  fis.close();

  sos.flush();

  sos.close();

  request.setAttribute("page",
page);

  return
mapping.findForward("list.view");

 }