I am taking some data from a database via a servlet and a db handler java class and hosting it at a url. Since the database is changing I'm taking care only to host the changes rather than the entire db data.
I'm getting the required functionality by a browser i.e after every (manual) reload, I'm getting the data as required by me,
1. at the first page load, entire data gets displayed.
2. at subsequent reloads, I get either null data if there is no change in the database, or the appended rows if the database extends. (the database can only extend).
But then in a java program, I'm not getting the same functionality. The java program using HttpUrlConnection
.
This is the code for the java client for servlet...
public class HTTPClient implements Runnable {
private CallbackInterface callbackinterface;
private URL url;
private HttpURLConnection http;
private InputStream response;
private String previousMessage = "";
public HTTPClient() {
try {
url = new URL("http://localhost:8080/RESTful-Server/index.jsp");
http = (HttpURLConnection) url.openConnection();
http.connect();
} catch (IOException e) {
}
}
@Override
public void run() {
while (true) {
try {
String currentmessage = "";
response = http.getInputStream();
if (http.getResponseCode() == HttpURLConnection.HTTP_OK) {
BufferedReader buffread = new BufferedReader(new InputStreamReader(response));
String line;
for (; (line = buffread.readLine()) != null;) {
currentmessage += line;
}
if ((!currentmessage.equals(previousMessage)
|| !previousMessage.equals(""))
&& !currentmessage.equals("")) {
//this.callbackinterface.event(currentmessage);\
System.out.println(currentmessage + "\t" + previousMessage);
}
previousMessage = currentmessage;
Thread.sleep(2500);
} else {
throw new IOException();
}
} catch (IOException | InterruptedException e) {
System.err.println("Exception" + e);
}
}
}
The shown class is a thread which read the connections every 2.5 s. If it gets something significant in the getline()
, it will issue a callback to a worker method, which takes care of remaining things.
I am thinking the issues is because of the class variable conn, and that reload as in the browser is not getting replicated..
Any idea how to do this?