Getting date from unknown Date format string

Question

If i have a string that contain a date in a format (unknown) "d/MM/YY" or "m:d:YYYY" etc.).

How could i parse it and get day,month,year values ?

I tried to parse them by filling an array with all format combinations , and try to parse the date with each one of them , i think it's a stupid solution !

Any ideas ?

Answer 1

your best bet is to use natty

very useful library,

here is an example of how to use it:

public static Date parse(String date) throws Exception {

    try{

        List<DateGroup> parse = new PrettyTimeParser().parseSyntax(date);
        return parse.get(0).getDates().get(0);

    }catch (Exception e){
        throw new Exception("unparseable date: " + date);
    }

}

Answer 2

Try to use this:

  public static void main(String []args){
        SimpleDateFormat dt = new SimpleDateFormat(); 
        TimeZone date;
        date = dt.getTimeZone();
  Calendar cal = Calendar.getInstance().getInstance(Locale.UK);
  cal.setTimeZone(date);
  int year = cal.get(Calendar.YEAR);
  int month = cal.get(Calendar.MONTH);
  int day = cal.get(Calendar.DAY_OF_MONTH);

        System.out.println(year);  
        System.out.println(month); 
        System.out.println(day);   
    }

Answer 3

If you unknown pattern format you can use something like this

    DateTimeFormatter formatter1 = DateTimeFormat.forPattern("d/MM/YY")
            .withLocale(Locale.UK);
    DateTimeFormatter formatter2 = DateTimeFormat.forPattern("m:d:YYYY")
            .withLocale(Locale.UK);
    ...
    DateTimeFormatter formatterN = DateTimeFormat.forPattern(...

    String stringDate = "08:18:2012";
    LocalDate date;
    try {
        date = formatter1.parseLocalDate(stringDate);
    } catch (Exception exp) {
       try {
          date = formatter2.parseLocalDate(stringDate);
       } catch (Exception exp) {
          ...
          date = formatterN.parseLocalDate(stringDate);
       }
    } 

OR using List:

    List<DateTimeFormatter> formatterList = new ArrayList<>();
    formatterList.add(DateTimeFormat.forPattern("d/MM/YY")
            .withLocale(Locale.UK));
    formatterList.add(DateTimeFormat.forPattern("m:d:YYYY")
            .withLocale(Locale.UK));
    ...
    formatterList.add(DateTimeFormat.forPattern(...

    String stringDate = "08:18:2012";
    LocalDate date;
    for(DateTimeFormatter formatter : formatterList) {
       try {
          return formatter.parseLocalDate(stringDate);
       } catch (Exception exp) {

       }
    } 

But it's impossible if you have pattern like "d/MM/YY" and "MM/d/YY", because you can recognize what string "01/01/15" means (where day and where month). Only if you have a lot of strings with one pattern you can statistically undestand what is day and what is month (month never be more then 12).

Answer 4

看看Cacovsky对这个问题的回答。

Answer 5

//download library:   org.ocpsoft.prettytime.nlp.PrettyTimeParser

String str = "2020.03.03";
Date date = new PrettyTimeParser().parseSyntax(str).get(0).getDates().get(0);
System.out.println(date)