关于Soap中的XmlPullParserException的一个问题

[zkw261123]

是这样的
我想编一个程序，实现安卓通过Web Service间接连接SQL Server。
Web Service已经写好了，调试通过。
问题出在安卓端：
程序捕获了一个XmlPullParserException异常，错误信息为：

org.xmlpull.v1.XmlPullParserException: expected: START_TAG 
{http://www.w3.org/2001/12/soap-envelope}
Envelope (position:START_TAG <{http://schemas.xmlsoap.org/soap/envelope/}
soap:Envelope>@1:208 in java.io.InputStreamReader@c4b0077)

我不知道问题在哪里，于是我想来这里问问各位。
附上代码
连接Web Service的代码：

import android.util.Log;

import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;

/**
 * Created by ZSpirytus on 2017/11/3.
 */

public class WebServiceConnector {

    private static final String TAG = "WebServiceConnector";
    private static final String WSDL_URI = "http://39.***.***.***:8080/?wsdl";
    private static final String NAMESPACE = "http://tempuri.org/";
    private static final String  METHOD_GETBASICINFOBYSNO = "getBasicInfoBySno";
    private static final String PARAM_SNO = "Sno";
    private static final String SOAPACTION = NAMESPACE+METHOD_GETBASICINFOBYSNO;

    public static String[] getBasicInfoBySno(String sno){
        SoapObject request = new SoapObject(NAMESPACE, METHOD_GETBASICINFOBYSNO);
        request.addProperty(PARAM_SNO ,sno);
        SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapSerializationEnvelope.VER12);
        envelope.bodyOut = request;
        envelope.dotNet = true;
        try{
            HttpTransportSE httpTransportSE = new HttpTransportSE(WSDL_URI);
            httpTransportSE.call(SOAPACTION, envelope);
        }catch (XmlPullParserException xmle){
            Log.d(TAG,"Class: GetStudentBasicInfoBySno catch an XmlPullParserException!");
            xmle.printStackTrace();
        }catch (IOException ie){
            ie.printStackTrace();
        }
        SoapObject object = (SoapObject) envelope.bodyIn;
        String[] result = new String[6];
        for(int i = 0;i<result.length;i++){
            result[i] = object.getProperty("getBasicInfoBySnoResult").toString();
        }
        return result;
    }

联网子线程的代码：

import android.os.AsyncTask;
import android.util.Log;

/**
 * Created by ZSpirytus on 2017/11/4.
 */

public class GetStudentBasicInfoBySno extends AsyncTask<String, Integer, String[]> {

    private static final String TAG = "GetStudentBasicInfoBySn";
    private String[] aaa = new String[6];
    @Override
    protected String[] doInBackground(String... params) {
        try {
            String[] result = WebServiceConnector.getBasicInfoBySno("15251102222");
            return result;
        } catch (Exception e) {
            e.printStackTrace();
            Log.d(TAG,"Class: GetStudentBasicInfoBySno catch an Exception!");
            return null;
        }
    }

    @Override
    protected void onPostExecute(String[] result) {
        aaa = result;
    }

    public String[] getResult(){
        return aaa;
    }
}

谢谢！！！