Question

I have some entries in log and I want to use Pattern matcher to get the entries out of log.

Log entries

1223-12-23 00:00:00 exception : 1223. Operation Cannot be done
1223-12-24 00:00:01 exception : 1221. Operation Cannot be done

I want to get entries like

String [] date = {1223-12-23 00:00:00, 1223-12-24 00:00:01}
String [] message = {exception : 1223. Operation Cannot be done, exception : 1221. Operation Cannot be done}

Is there an efficient way to do this.

Answer 1

Better than my other answer:

// dynamic list of strings for dates and messages
List<String> dates = new ArrayList<>();
List<String> messages = new ArrayList<>();
// split your logfile by line
String[] lines = yourLogFileContentAsString.split("\n");
for (String line : lines) {
    // dates are characters 0-19
    dates.add(line.substring(0, 20));
    // message starts at character 21
    messages.add(line.substring(21);
}
// you wanted arrays
String[] datesArray = dates.toArray(new String[0]);
String[] messagesArray = messages.toArray(new String[0]);