public void download(ByteArrayOutputStream byteArrayOutputStream, HttpServletResponse response, String returnName) throws IOException{
	//設定響應檔案型別  MINI   可以在tomcat下的cof/web.xml 可以查到
		response.setContentType("application/octet-stream;charset=utf-8");
			//儲存的檔名,必須和頁面編碼一致,否則亂碼
		returnName = response.encodeURL(new String(returnName.getBytes(),"iso8859-1"));		
		response.addHeader("Content-Disposition",   "attachment;filename=" + returnName);  
		response.setContentLength(byteArrayOutputStream.size());
		
		ServletOutputStream outputstream = response.getOutputStream();	//取得輸出流
		byteArrayOutputStream.writeTo(outputstream);					//寫到輸出流
		byteArrayOutputStream.close();									//關閉
		outputstream.flush();											//刷資料
	}