咸阳市委:在eclipse中如何编码实现下载功能？

需要下载成excel形式，可是我写的代码只生成了个空的excel，怎样才能把数据写进去呢？请高手指点，越快越好，谢谢啦！
我在jsp页中的代码如下：
<%@page language="java" contentType="application/x-msdownload" import="java.io.*,java.net.*"%>

<% response.reset();
response.setContentType("application/x-download");
System.out.println(this.getClass().getClassLoader().getResource("/").getPath());
String filenamedownload = this.getClass().getClassLoader().getResource("/").getPath() + "/../../111.xls";
String filenamedisplay = "111.xls";
filenamedisplay = URLEncoder.encode(filenamedisplay,"UTF-8");
response.addHeader("Content-Disposition","attachment;filename=" + filenamedisplay);

OutputStream output = null;
FileInputStream fis = null;
try
{
output = response.getOutputStream();
fis = new FileInputStream(filenamedownload);

byte[] b = new byte[1024];
int i = 0;

while((i = fis.read(b)) > 0)
{
output.write(b, 0, i);
}
output.flush();
}
catch(Exception e)
{
System.out.println("Error!");
e.printStackTrace();
}
finally
{
if(fis != null)
{
fis.close();
fis = null;
}
if(output != null)
{
output.close();
output = null;
}
}%>