安卓，https方式发送xml文件到服务器，服务器返回一个xml文件，解析这个xml文件，

安卓，https方式发送xml文件到服务器，服务器返回一个xml文件，解析这个xml文件，解析得到信息决定是否更新版本

就是https方式发送，接受文件。不明白问题是？

public class MainActivity extends Activity {
private static String xml="<?xml version=\"1.0\" encoding=\"utf-8\"?>......"
+ "20140429113321"
+ " 用户名用户快钱会员号M001DADEQQWQW"
+ "DASASADASADGGDSLKMMSDLKL";
private static String TAG=MainActivity.class.getSimpleName();
private Button button;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mainactivity);  
    if (android.os.Build.VERSION.SDK_INT > 2.3) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
    }

      Log.d(TAG, "onCreate");
      button=(Button)findViewById(R.id.update_button);
      button.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            try {
                sendXmlReturnRespCode();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }   
    });
}
protected String sendXmlReturnRespCode() throws Exception{
    String  url="https://XXXXXXXX";
    byte[] data = xml.getBytes("UTF-8");
    HttpsURLConnection conn=(HttpsURLConnection) new URL(url).openConnection();
    conn.setRequestMethod("POST");
    conn.setRequestProperty("Content-Type", "msgContent/xml:charset=UTF-8");
    conn.setRequestProperty("Charset", "UTF-8"); 
    conn.setRequestProperty("Content_length", String.valueOf(data.length));
    conn.setDoOutput(true);
    conn.setDoInput(true);
    conn.connect();
    OutputStream outStream= conn.getOutputStream();  
    outStream.write(data);
    conn.getOutputStream().flush();
    conn.getOutputStream().close();
    int recode=conn.getResponseCode();
    String responseCode="";
    responseCode=String.valueOf(recode);
    if(responseCode.equals("00")){
        Log.d(TAG, "发送成功");
    }
    else {
        Log.d(TAG, "发送失败");
    }
    BufferedReader br=new BufferedReader(new InputStreamReader(conn.getInputStream()));
    String str=br.readLine();
    Log.d(TAG, "返回码是"+str);
    return str;
  }
}

能帮忙看看哪儿出错了么

能帮忙看看是哪儿错了么