Android從網路下載XML輸出資料流或者字串（知識積累）

public String downloadXML(final String urlStr)     {    StringBuffer sb=new StringBuffer();    String line=null;    BufferedReader buffer=null;        try {    URL url=new URL(urlStr);        HttpURLConnection urlConn=(HttpURLConnection)url.openConnection();        InputStream inputStream = urlConn.getInputStream();        buffer=new BufferedReader(new InputStreamReader(inputStream));        while ((line= buffer.readLine()) != null) {sb.append(line);}} catch (Exception e) {e.printStackTrace();} finally{try {buffer.close();} catch (Exception e2) {e2.printStackTrace();}}            return sb.toString();    }