How can I get and extract a number from website using Java?

Minh Quang Ngo :

I want to get and extract the number after unixtime from this link. http://worldtimeapi.org/api/ip.txt I use below code to get data but seem it wrong

  public String getData() throws IOException {
String httpUrl = "http://worldtimeapi.org/api/ip.txt";
URL url = new URL(httpUrl);
URLConnection urlConnection = url.openConnection();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
String response = bufferedReader.readLine();
bufferedReader.close();

Also, how can I test for network error by using mockito and Junit?

Jacob G. :

One solution is to use Java's HttpClient to issue a GET request to the URL and have it return a response as a String. After that, you can use a simple regular expression to extract the value that you're looking for:

Pattern pattern = Pattern.compile("unixtime: (\\d+)", Pattern.MULTILINE);

HttpClient client = HttpClient.newHttpClient();

HttpResponse<String> response = client.send(HttpRequest.newBuilder()
        .GET()
        .uri(new URI("http://worldtimeapi.org/api/ip.txt"))
        .build(), HttpResponse.BodyHandlers.ofString());

Matcher matcher = pattern.matcher(response.body());

if (matcher.find()) {
    System.out.println(matcher.group(1));
}

Output:

1543639818

Just remember to handle any checked exceptions correctly.