HttpURLConnection 에서 세션 유지하기(쿠키 사용)

package com.example.zdgtest2;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;
import java.util.Map;

import android.util.Log;

public class GetHttp {
 final static double VERSION = 1.20141016;
 static final int ERROR_CODE_HTTP_NOT_FOUND = -404;
 static final int ERROR_CODE_HTTP_UNAUTHORIZED = -401;
 static final int ERROR_CODE_HTTP_ELSE = -1;
 static final int ERROR_CODE_HTTP_EXCEPTION = -1000;
 static final int ERROR_CODE_NOERROR = 0;
 byte[] htmlByte = null;
 int errorCode = 0;
 boolean bUseCache = true;
 boolean m_session = false;
 String m_cookies = "";
 public String getString() {
  try {
   return new String(htmlByte, "UTF-8");
  } catch (UnsupportedEncodingException e) {
   e.printStackTrace();
  }
  return null;
 }
 public byte[] getByte() {
  return htmlByte;  
 }
 public int getErrorCode() {
  return errorCode;
 }
 public boolean execute(String addr) {
  return execute(addr, 5, 10);
 }
 public void saveCookie( HttpURLConnection conn)
 {
  
     Map<String, List<String>> imap = conn.getHeaderFields( ) ;
     if( imap.containsKey( "Set-Cookie" ) )
     {
   List<String> lString = imap.get( "Set-Cookie" ) ;
   for( int i = 0 ; i < lString.size() ; i++ ) {
    m_cookies += lString.get( i ) ;
   }
   Log.e("zdg",m_cookies);
         m_session = true ;
     } else {
      m_session = false ;
     }
 }
 // 참고 소스:http://markan82.tistory.com/32
 public boolean execute(String addr, int connTimeOutSec, int readTimeOutSec) {
  boolean retval = true;
  errorCode = ERROR_CODE_NOERROR;
  try {
   URL url = new URL(addr);
   Log.e("zdg",addr);
   HttpURLConnection conn = (HttpURLConnection) url.openConnection();
   if( conn != null ) {
    conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
    if( m_session ) {
     conn.setRequestProperty( "Cookie", m_cookies );
    }
    conn.setConnectTimeout(1000*connTimeOutSec);
    conn.setReadTimeout(1000*readTimeOutSec);
    conn.setUseCaches(bUseCache);
    conn.setDoInput(true);

    int resCode = conn.getResponseCode();
    saveCookie(conn);

    if( resCode == HttpURLConnection.HTTP_OK ) {
     htmlByte = inputStreamToByte(conn.getInputStream());
     if(htmlByte == null || htmlByte.length == 0){
      errorCode = ERROR_CODE_HTTP_ELSE;
      retval = false;
     }
    } else if( resCode == HttpURLConnection.HTTP_NOT_FOUND ) {
     errorCode = ERROR_CODE_HTTP_NOT_FOUND;
     retval = false;
    } else if( resCode == HttpURLConnection.HTTP_UNAUTHORIZED ) {
     errorCode = ERROR_CODE_HTTP_UNAUTHORIZED;
     retval = false;
    } else {
     errorCode = ERROR_CODE_HTTP_ELSE;
     retval = false;
    }
    // DISCONNECT 
    conn.disconnect();
   } else {
    errorCode = ERROR_CODE_HTTP_ELSE;
    retval = false;
   }
  } catch(Exception e) {
   e.printStackTrace();
   errorCode = ERROR_CODE_HTTP_EXCEPTION;
   retval = false;
  }
  return retval;
 }
 private byte[] inputStreamToByte(InputStream in)
 {
  final int BUF_SIZE = 1024; 
  ByteArrayOutputStream out = new ByteArrayOutputStream();
  byte[] buffer = new byte[BUF_SIZE];
  try {
   int length;
   while ((length = in.read(buffer)) != -1) out.write(buffer, 0, length);
  } catch (IOException e) {
   e.printStackTrace();
   return null;
  }
  return out.toByteArray();
 }
}

 private void webTest() {
  Thread nthread = new Thread(new Runnable() {
    public void run() {
     try {
      GetHttp html = new GetHttp();
    if(html.execute("http://xxx:8080/jsp/admin/user/userCtrl.jsp?id=xxx&pass=xxx",30,30)!=true)
    {
     printLog("error "+html.errorCode);
    }
    if ( html.getByte() != null && html.getByte().length > 0 ){
     Utils.fileWriteByte("/sdcard/Download/test1.html",html.getByte());
    }
    html.execute("http://xxx:8080/jsp/main.jsp",30,30);
    if ( html.getByte() != null && html.getByte().length > 0 ){
     Utils.fileWriteByte("/sdcard/Download/test2.html",html.getByte());
    }
     } catch (Throwable ex) {
      ex.printStackTrace();
     }
    }
   });
  nthread.start();
 }