Java date with different formats

Question

Hey Im using the code below to parse dates in different formats.

The trubel is, it takes the first format and parses the date even if it doesn't fit.

public static Date parseDate(String date) {
    date = date.replaceAll("[-,.;:_/&()+*# ']", "-");
    System.out.print(date);
    List<String> formatStrings = Arrays.asList("d-M-y","y-M-d");
    for (String formatString : formatStrings) {
        try {
            System.out.println(new SimpleDateFormat(formatString).parse(date));
            return new SimpleDateFormat(formatString).parse(date);
        } catch (Exception e) {
        }
    }
    return null;
}

Console:

1994-02-13
Wed Jul 18 00:00:00 CEST 2018

OR

13-02-1994
Sun Feb 13 00:00:00 CET 1994

So I don't get why does the first format allways parse?

Because you're parsing the string. Not formatting it – Jay Nov 25 '17 at 15:46 — Jay, Nov 25 '17 at 15:46

Mustapha Belmokhtar · Answer 1 · 2017-11-25T17:10:26.847

2

your loop stops at the very first returnstatement, remove the return statement from your loop, then it will lopp all over your date formats.

EDIT : as requested in the comments:

  public static Date parseDate(String date) {
    Date dateToReturn = null;
    date = date.replaceAll("[,\\.;:_/&\\(\\)\\+\\*# ']", "-");
    String formatString = "d-M-y";
    if (date.matches("\\d{4}-\\d{2}-\\d{2}")) {
        formatString = "y-M-d";
    }
    try {
        dateToReturn = new SimpleDateFormat(formatString).parse(date);
    } catch (Exception e) {
        System.out.println("the given date does not math this format " + formatString);
    }
    return dateToReturn;
}

Here above I considered you only have two possible formats.

edited Nov 25 '17 at 17:10

answered Nov 25 '17 at 15:49

Mustapha Belmokhtar

1,231
8
21

I want to return a Date, but it should do the return if there is an exception? – Zero Soul Eater Nov 25 '17 at 16:22
okay, but based on which format ? , because having two formats confused me – Mustapha Belmokhtar Nov 25 '17 at 16:23
well I use this in a web backend and I could be given in different formats from the browser – Zero Soul Eater Nov 25 '17 at 16:41
I edited the answer, I hope it helps – Mustapha Belmokhtar Nov 25 '17 at 17:10

clay · Accepted Answer · 2017-11-25T17:30:31.210

Here is a simpler example in jshell. the "d-M-y" does parse both because it defaults to lenient. If you do setLenient(false) it will exception on the date in the other format.

|  Welcome to JShell -- Version 9.0.1
|  For an introduction type: /help intro

jshell> java.text.SimpleDateFormat dmy = new java.text.SimpleDateFormat("d-M-y");
dmy ==> java.text.SimpleDateFormat@596ca10

jshell> dmy.parse("13-02-1994")
$2 ==> Sun Feb 13 00:00:00 CST 1994

jshell> dmy.parse("1994-02-13")
$3 ==> Wed Jul 18 00:00:00 CDT 2018

jshell> dmy.isLenient()
$4 ==> true

jshell> dmy.setLenient(false)

jshell> dmy.parse("1994-02-13")
|  java.text.ParseException thrown: Unparseable date: "1994-02-13"
|        at DateFormat.parse (DateFormat.java:388)
|        at (#6:1)

FYI, the Java 8+ API way to do this:

jshell> java.time.format.DateTimeFormatter dmy = java.time.format.DateTimeFormatter.ofPattern("dd-MM-yyyy");
dmy ==> Value(DayOfMonth,2)'-'Value(MonthOfYear,2)'-'Value(YearOfEra,4,19,EXCEEDS_PAD)

jshell> java.time.LocalDate.parse("13-02-1994", dmy)
$2 ==> 1994-02-13

jshell> java.time.LocalDate.parse("1994-02-13", dmy)
|  java.time.format.DateTimeParseException thrown: Text '1994-02-13' could not be parsed at index 2
|        at DateTimeFormatter.parseResolved0 (DateTimeFormatter.java:1988)
|        at DateTimeFormatter.parse (DateTimeFormatter.java:1890)
|        at LocalDate.parse (LocalDate.java:428)
|        at (#3:1)

I certainly recommend the Java 8 way. Thank you for supplying this. — Ole V.V., Nov 25 '17 at 21:35

Java date with different formats

2 Answers2