直接通過Response輸出流寫文件，瀏覽器表現為下載文件

response.setContentType("application/x-download");
response.addHeader("Content-Disposition", "attachment;filename="+new String( "中文".getBytes("utf-8"), "ISO8859-1" )+"文件類型");

OutputStream out = response.getOutputStream();

向out中寫入流

out.flush();

response.flushBuffer();

即可