问下这样写为什么请求到不了服务器断

Question

public void save_record_db() {
System.out.println("come in  save_record_db");

try {
URL url=new URL("http://localhost:8080/depot/GeneralHandleSvt?reqType=utility.UtilActionHandler.save_record");
URLConnection uc=url.openConnection();
uc.setDoOutput(true);
uc.setDoInput(true);
uc.setUseCaches(true);
//uc.setRequestProperty("Content_type","application/x-www-form-urlencoded");

ObjectOutputStream dos=new ObjectOutputStream(uc.getOutputStream());
//dos.writeBytes("");
ArrayList<String []> list=new ArrayList();
list=iw.getAllLine(_file);
dos.writeObject(list);
dos.flush();
dos.close();
}
catch(IOException e) {
e.printStackTrace();
}
}