Todd Todd - 1 month ago 14
Java Question

Java 8 Date equivalent to Joda's DateTimeFormatterBuilder with multiple parser formats?

I currently have a Joda date parser that uses the DateTimeFormatterBuilder with half a dozen different date formats that I may receive.

I'm migrating to Java 8's Date routines and don't see an equivalent.

How can I do something like this using Java 8 Dates?

DateTimeParser[] parsers = {
DateTimeFormat.forPattern( "yyyy/MM/dd HH:mm:ss.SSSSSS" ).getParser() ,
DateTimeFormat.forPattern( "yyyy-MM-dd HH:mm:ss" ).getParser() ,
DateTimeFormat.forPattern( "ddMMMyyyy:HH:mm:ss.SSS Z" ).getParser() ,
DateTimeFormat.forPattern( "ddMMMyyyy:HH:mm:ss.SSS" ).getParser() ,
DateTimeFormat.forPattern( "ddMMMyyyy:HH:mm:ss.SSSSSS" ).getParser() ,
DateTimeFormat.forPattern( "yyyy-MM-dd HH:mm:ss.SSS" ).getParser()
};

DateTimeFormatter dateTimeFormatterInput = new DateTimeFormatterBuilder()
.append( null, parsers ).toFormatter();

Answer

There is no direct facility to do this, but you can use optional sections. Optional sections are enclosed inside squared brackets []. This allows for the whole section of the String to parse to be missing.

DateTimeFormatter formatter = DateTimeFormatter.ofPattern(""
    + "[yyyy/MM/dd HH:mm:ss.SSSSSS]"
    + "[yyyy-MM-dd HH:mm:ss[.SSS]]"
    + "[ddMMMyyyy:HH:mm:ss.SSS[ Z]]"
);

This formatter defines 3 grand optional sections for the three main patterns you have. Each of them is inside its own optional section.

Working demo code:

public static void main(String[] args) {
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern(""
        + "[yyyy/MM/dd HH:mm:ss.SSSSSS]"
        + "[yyyy-MM-dd HH:mm:ss[.SSS]]"
        + "[ddMMMyyyy:HH:mm:ss.SSS[ Z]]"
    , Locale.ENGLISH);
    System.out.println(LocalDateTime.parse("2016/03/23 22:00:00.256145", formatter));
    System.out.println(LocalDateTime.parse("2016-03-23 22:00:00", formatter));
    System.out.println(LocalDateTime.parse("2016-03-23 22:00:00.123", formatter));
    System.out.println(LocalDateTime.parse("23Mar2016:22:00:00.123", formatter));
    System.out.println(LocalDateTime.parse("23Mar2016:22:00:00.123 -0800", formatter));
}