下载文件的问题？

[xfv]

<%@ page import="java.io.*;"%>
<%
try {

String url = "c:/file/新建文本文档.txt";// 实际文件路径
String name = "默认中文文件名.txt";//显示给用户看的文件名，即ie弹出下载框中提示保存的文件名
response.reset();
response.setContentType("bin");
response.setHeader("Content-Disposition", "attachment; filename="+name);//处理默认文件名的中文问题

ServletOutputStream os = response.getOutputStream();
FileInputStream in = new FileInputStream(url);
byte[] data = new byte[1024];
int temp = -1;
while((temp=in.read(data))!= -1){
os.write(data,0,temp);
os.flush();
}//while//
in.close();
os.close();
} catch(Exception e) {
System.out.print(e.toString());
}
%>

运行上面的程序，提示错误：

org.apache.jasper.JasperException: getOutputStream() has already been called for this response

怎么解决，请高手相助。