简单文件下载

    // 1先创建工作簿对
    HSSFWorkbook workbook2003 = new HSSFWorkbook();
    // 2创建工作表对象并命名
    HSSFSheet sheet = workbook2003.createSheet("学生信息统计表");
    //3 创建行创建了第一行
     HSSFRow row = sheet.createRow(0);
     //4在第一行创建一列
     HSSFCell nameCell = row.createCell(0);  

     nameCell.setCellValue("测试");
     //5创建文件
     File file = new File("d:\\123.xls");
      FileOutputStream fos = null;
     try {
         fos = new FileOutputStream(file);
         workbook2003.write(fos);
     } catch (Exception e) {
         e.printStackTrace();
     } finally {
     if (fos != null) {
     try {
                 fos.close();
             } catch (Exception e) {
                 e.printStackTrace();
             }
         }
     }
      //处理文件名
   String realname = "d:\\123.xls";
   FileInputStream in;
   //创建输出流
   OutputStream out;
    //设置响应头，控制浏览器下载该文件
    try {
        response.setHeader("content-disposition", "attachment; filename=" + URLEncoder.encode(realname, "UTF-8"));
         //读取要下载的文件，保存到文件输入流

        in = new FileInputStream("d:\\123.xls");

        out = response.getOutputStream();
        //创建缓冲区
        byte buffer[] = new byte[1024];
        int len = 0;
        //循环将输入流中的内容读取到缓冲区当中
        while((len=in.read(buffer))>0){
            //输出缓冲区的内容到浏览器，实现文件下载
            out.write(buffer, 0, len);
        }
        //关闭文件输入流
          in.close();
        //关闭输出流
        out.close();
    } catch (Exception e) {
        e.printStackTrace();
    }finally{

    }