如何仅监视静态 html 中的网页更改

问：

我创建了一个应用程序来监控网页。诀窍是，当广告发生变化时，我的应用程序会检测到变化并触发警报。

如何解决这个问题？

这是我用于获取html的代码

                    HttpClient client = new DefaultHttpClient();

                    HttpGet get = new HttpGet( urlValue );

                    HttpResponse response;
                    try {
                        response = client.execute( get );
                        HttpEntity entity = response.getEntity();
                        if (entity != null) {
                            InputStream is = entity.getContent();
                            BufferedReader reader = new BufferedReader(
                                    new InputStreamReader( is ) );
                            StringBuilder sb = new StringBuilder();

                            String result = null;
                            try {
                                while( ( result = reader.readLine() ) != null )
                                    sb.append(result).append("\n");
                            } catch ( IOException e ) {
                                Log.e( "readFromUrl", e.getMessage() );
                            } finally {
                                try {
                                    is.close();
                                } catch ( IOException e ) {
                                    Log.e( "readFromUrl", e.getMessage() );
                                }
                            }

                            line = sb.toString();
                            is.close();
                        }
                    } catch( Exception e ) {
                        Log.e( "readFromUrl", e.getMessage() );
                    }

或者，jsoup 可能吗？