CODEWITHSUNDEEP
javajodatimedatetime-formatdatetime-parsing
flyingfox
flyingfox

Reputation: 13506

How to parse two similar string to datetime in one formatter with joda?

Now I have two different formats of date written in string:

String date1 = "2018-10-12 18:01:01";// yyyy-MM-dd HH:mm:ss
String date2 = "2018-10-12 18:01";//yyyy-MM-dd HH:mm

I am using joda and I want to convert the string to DateTime,the basic way is to use two formatter to parse each of them:

DateTimeFormatter formatter1 = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss");
DateTimeFormatter formatter2 = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm");
DateTime dt1 = formatter1.parseDateTime(date1);
DateTime dt2 = formatter2.parseDateTime(date2);

Above code blocks works fine but it created two formatter,since the date formate is very similar(the latter one just lack of seconds),I am wonder if there is a way that I can just use one formatter to parse all of them or I have to use two formatter?

Note: due to the production enviroment limit,I can not use java8 now,so I want to the answer based on joda

Thanks in advance!

I just tried as below,and got IllegalArgumentException： Invalid format

DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss");
DateTime dt1 = formatter.parseDateTime(date1);
DateTime dt2 = formatter.parseDateTime(date2);

Upvotes: 2

Views: 258

Answers (3)

Anonymous
Anonymous

Reputation: 86276

Two options:

  1. Use java.time, the modern Java date and time API through the ThreeTen Backport library.
  2. Use Joda-Time as you are already doing.

ThreeTen Backport

Two quotes from the Joda-Time home page:

Users are now asked to migrate to java.time (JSR-310).

Note that Joda-Time is considered to be a largely “finished” project. No major enhancements are planned. If using Java SE 8, please migrate to java.time (JSR-310).

The good news is you can migrate even if using Java 6 or 7. The developers of java.time (lead by Stephen Colebourne, also the lead developer of Joda-Time) have also developed the ThreeTen Backport, the backport of java.time for Java 6 and 7. See the link at the bottom.

Anton Balaniuc is already showing the code in his good answer, so there’s no use for me to repeat that here.

Joda-Time

    String date1 = "2018-10-12 18:01:01";// yyyy-MM-dd HH:mm:ss
    String date2 = "2018-10-12 18:01";//yyyy-MM-dd HH:mm
    DateTimeFormatter parser = new DateTimeFormatterBuilder()
                    .appendPattern("yyyy-MM-dd HH:mm")
                    .appendOptional(DateTimeFormat.forPattern(":ss").getParser())
                    .toFormatter();
    DateTime dt1 = parser.parseDateTime(date1);
    DateTime dt2 = parser.parseDateTime(date2);
    System.out.println("dt1: " + dt1);
    System.out.println("dt2: " + dt2);

On my computer in Europe/Copenhagen time zone the output from this snippet was:

dt1: 2018-10-12T18:01:01.000+02:00
dt2: 2018-10-12T18:01:00.000+02:00

As you can see, the key to specifying optional parts in the format is the appendOptional method of DateTimeFormatterBuilder.

Links

Upvotes: 2

Anton Balaniuc
Anton Balaniuc

Reputation: 11739

You can indicate that some parts of the format are optional using [] 

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm[:ss]");
LocalDateTime dateTime = LocalDateTime.parse("2018-10-12 18:01:01", formatter);
LocalDateTime dateTime1 = LocalDateTime.parse("2018-10-12 18:01", formatter);
System.out.println(dateTime + " " + dateTime1);

result is 

2018-10-12T18:01:01 2018-10-12T18:01

Please see Patterns for Formatting and Parsing section for more info.

Upvotes: 3

Mladen Savić
Mladen Savić

Reputation: 472

You can use DateTimeFormatterBuilder class, something like this.

  private DateTimeFormatter formatterBuilder() {
        return new DateTimeFormatterBuilder()
                .appendPattern("yyyy-MM-dd HH:mm")
                .optionalStart().appendPattern(":ss").optionalEnd()
                .toFormatter();
    }

Upvotes: 0

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