android ksoap2 访问webservice，连续两次调用时，第二次调用异常（转）

 String data="";

String requestData="<?xml version="1.0" encoding="utf-8"?>rn"+
"<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">rn"
  +"<soap:Header>rn"+
    "<AuthHeader xmlns="http://www.111cn.net/PhoneClient/">rn"+
     "<UserId>"+userID+"</UserId>rn"+
    "</AuthHeader>rn"+
  "</soap:Header>rn"+
  "<soap:Body>rn"+
    "<GetVcardJson xmlns="http://www.111cn.net/PhoneClient/">rn"+
      "<vcardUserNo>"+userNo+"</vcardUserNo>rn"+
    "</GetVcardJson>rn"+
  "</soap:Body>rn"+

"</soap:Envelope>";

try{
URL url =new URL(ServerUrl);
HttpURLConnection con=(HttpURLConnection)url.openConnection();
byte[] bytes=requestData.getBytes("utf-8");
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
con.setRequestMethod("POST");
con.setRequestProperty("Content-Type", "text/xml;charset=utf-8");
con.setRequestProperty("SOAPAction",soapAction);
con.setRequestProperty("Content-Length",""+bytes.length);
OutputStream outStream=con.getOutputStream();
outStream.write(bytes);
outStream.flush();
outStream.close();
InputStream inStream=con.getInputStream();

data=parser(inStream);

}catch(XmlPullParserException e){
e.printStackTrace();
}catch(IOException e){
e.printStackTrace();
}
return data;
}