socket发送数据

String date = request.getParameter("date");
List l =this.getBillService().getPayData(date);
StringBuffer sb=new StringBuffer();
for(int i=0;i<l.size();i++){
WtPepBillpay w =(WtPepBillpay)l.get(i);
sb.append(Util.getNewString(w.getPayJsck(), 12)+",");
sb.append(Util.getNewString(w.getPayDate(), 10)+",");
......
}
response.setContentType("octets/stream");
response.addHeader("Content-Disposition","attachment;filename="+date+"PUB");
OutputStream fileOut = response.getOutputStream();
fileOut.write(sb.toString().getBytes());
fileOut.flush();
fileOut.close();

端口在起tomcat的时候已经打开