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Java8 equivalent of Joda's ISODateTimeFormat.dateTimeParser()?

Tags:

java

java-8

jodatime

I can't figure out how to get Java8's DateTime parsing to behave like the Joda equivalent I am attempting to replace. The issue is that Joda's ISODateTimeFormat.dateTimeParser(); allowed me to input as little as YYYY and it would still work (2016 would become 2016-01-01T00:00:00.000Z", for example). How can I get this same behavior from Java8?

The code is simple enough...

import java.time.OffsetDateTime;
import java.time.temporal.ChronoField;

import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.ISODateTimeFormat;

public class Java8OffsetDateTime {
  public static void main(String[] args) {
    String[] candidates =
        { "2016-11-21T17:54:51.841Z",
            "2016-11-21T09:54:51.841-08:00",
            "2016", // Java8 no can do?
            "2016-11", // Java8 no can do?
            "2016-11-21", // Java8 no can do?
            "2016-11-21T01", // Java8 no can do?
            "2016-11-21T01:02", // Java8 no can do?
            "2016-11-21T01:02:03" // Java8 no can do?
        };
    DateTimeFormatter JodaDateTimeFormatter = ISODateTimeFormat.dateTimeParser();
    for (String candidate : candidates) {
      System.out.println("\ncandidate:\t\"" + candidate + "\"");
      DateTime jodaDateTime = JodaDateTimeFormatter.parseDateTime(candidate);
      System.out.println("Joda:\t" + jodaDateTime);
      try {
        OffsetDateTime java8OffsetDateTime = OffsetDateTime.parse(candidate);
        System.out.println("Java8:\t" + java8OffsetDateTime);
        long jodaMillis = jodaDateTime.getMillis();
        long javaMillis = java8OffsetDateTime.toInstant().toEpochMilli();
        System.out.printf("jodaMillis:%d %s javaMillis:%d\n",
            jodaMillis,
            (jodaMillis==javaMillis) ? "==" : "!=",
            javaMillis);
      } catch (Exception e) {
        e.printStackTrace();
      }
    }
  }
}

The results are the challenge...

$ java -cp ~/work/joda-time-2.9.6/joda-time-2.9.6.jar:. Java8OffsetDateTime

candidate:  "2016-11-21T17:54:51.841Z"
Joda:   2016-11-21T09:54:51.841-08:00
Java8:  2016-11-21T17:54:51.841Z
jodaMillis:1479750891841 == javaMillis:1479750891841

candidate:  "2016-11-21T09:54:51.841-08:00"
Joda:   2016-11-21T09:54:51.841-08:00
Java8:  2016-11-21T09:54:51.841-08:00
jodaMillis:1479750891841 == javaMillis:1479750891841

candidate:  "2016"
Joda:   2016-01-01T00:00:00.000-08:00
java.time.format.DateTimeParseException: Text '2016' could not be parsed at index 4
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:387)
    at Java8OffsetDateTime.main(Java8OffsetDateTime.java:26)

candidate:  "2016-11"
Joda:   2016-11-01T00:00:00.000-07:00
java.time.format.DateTimeParseException: Text '2016-11' could not be parsed at index 7
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:387)
    at Java8OffsetDateTime.main(Java8OffsetDateTime.java:26)

candidate:  "2016-11-21"
Joda:   2016-11-21T00:00:00.000-08:00
java.time.format.DateTimeParseException: Text '2016-11-21' could not be parsed at index 10
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:387)
    at Java8OffsetDateTime.main(Java8OffsetDateTime.java:26)

candidate:  "2016-11-21T01"
Joda:   2016-11-21T01:00:00.000-08:00
java.time.format.DateTimeParseException: Text '2016-11-21T01' could not be parsed at index 13
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:387)
    at Java8OffsetDateTime.main(Java8OffsetDateTime.java:26)

candidate:  "2016-11-21T01:02"
Joda:   2016-11-21T01:02:00.000-08:00
java.time.format.DateTimeParseException: Text '2016-11-21T01:02' could not be parsed at index 16
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:387)
    at Java8OffsetDateTime.main(Java8OffsetDateTime.java:26)

candidate:  "2016-11-21T01:02:03"
Joda:   2016-11-21T01:02:03.000-08:00
java.time.format.DateTimeParseException: Text '2016-11-21T01:02:03' could not be parsed at index 19
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:402)
    at java.time.OffsetDateTime.parse(OffsetDateTime.java:387)
    at Java8OffsetDateTime.main(Java8OffsetDateTime.java:26)

How do I get rid of those java.time.format.DateTimeParseExceptions from the "Java8 no can do?" cases?

like image 949
Bob Kuhar Avatar asked Nov 21 '16 19:11

Bob Kuhar

3 Answers

Thanks to @Tunaki for suggesting the alternative syntax. This will help you parse your input values that you have provided. Adjust accordingly.

OffsetDateTime java8OffsetDateTime = OffsetDateTime.parse(candidate, offsetDateTimeFormatter );

DateTimeFormatter customOffsetDateTimeFormatter = new DateTimeFormatterBuilder().appendPattern("yyyy[-MM][-dd['T'HH[:mm[:ss]]]][.SSSXXX]")
            .parseDefaulting(ChronoField.MONTH_OF_YEAR, 1)
            .parseDefaulting(ChronoField.DAY_OF_MONTH, 1)
            .parseDefaulting(ChronoField.HOUR_OF_DAY, 0)
            .parseDefaulting(ChronoField.MINUTE_OF_HOUR, 0)
            .parseDefaulting(ChronoField.SECOND_OF_MINUTE, 0)
            .parseDefaulting(ChronoField.NANO_OF_SECOND, 0)
            .parseDefaulting(ChronoField.OFFSET_SECONDS, ZoneOffset.of("-08:00").getTotalSeconds())
            .toFormatter();

Test Case: (-06:00 Offset)

import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.temporal.ChronoField;
public class App 
 {
    public static void main(String[] args) {
        String[] candidates =
            {"2016-11-21T15:54:51.841Z",
                 "2016-11-21T09:54:51.841-06:00",
                    "2016", // Java8 no can do?
                    "2016-11", // Java8 no can do?
                    "2016-11-21", // Java8 no can do?
                    "2016-11-21T01", // Java8 no can do?
                    "2016-11-21T01:02", // Java8 no can do?
                    "2016-11-21T01:02:03" // Java8 no can do?*/
            };

        DateTimeFormatter customOffsetDateTimeFormatter = new DateTimeFormatterBuilder().appendPattern("yyyy[-MM][-dd['T'HH[:mm[:ss]]]][.SSSXXX]")
            .parseDefaulting(ChronoField.MONTH_OF_YEAR, 1)
            .parseDefaulting(ChronoField.DAY_OF_MONTH, 1)
            .parseDefaulting(ChronoField.HOUR_OF_DAY, 0)
            .parseDefaulting(ChronoField.MINUTE_OF_HOUR, 0)
            .parseDefaulting(ChronoField.SECOND_OF_MINUTE, 0)
            .parseDefaulting(ChronoField.NANO_OF_SECOND, 0)
            .parseDefaulting(ChronoField.OFFSET_SECONDS, ZoneOffset.of("-06:00").getTotalSeconds())
            .toFormatter();

    org.joda.time.format.DateTimeFormatter jodaDateTimeFormatter = ISODateTimeFormat.dateTimeParser();
    for (String candidate : candidates) {
        System.out.println("\ncandidate:\t\"" + candidate + "\"");
        DateTime jodaDateTime = jodaDateTimeFormatter.parseDateTime(candidate);
        System.out.println("Joda:\t" + jodaDateTime);
        try {
            OffsetDateTime java8OffsetDateTime = OffsetDateTime.parse(candidate,customOffsetDateTimeFormatter);
            System.out.println("Java8:\t" + java8OffsetDateTime);
            long jodaMillis = jodaDateTime.getMillis();
            long javaMillis = java8OffsetDateTime.toInstant().toEpochMilli();
            System.out.printf("jodaMillis:%d %s javaMillis:%d\n",
                    jodaMillis,
                    (jodaMillis == javaMillis) ? "==" : "!=",
                    javaMillis);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Output: (-06:00 Offset)

    candidate:  "2016-11-21T15:54:51.841Z"
    Joda:   2016-11-21T09:54:51.841-06:00
    Java8:  2016-11-21T15:54:51.841Z
    jodaMillis:1479743691841 == javaMillis:1479743691841

    candidate:  "2016-11-21T09:54:51.841-06:00"
    Joda:   2016-11-21T09:54:51.841-06:00
    Java8:  2016-11-21T09:54:51.841-06:00
    jodaMillis:1479743691841 == javaMillis:1479743691841

    candidate:  "2016"
    Joda:   2016-01-01T00:00:00.000-06:00
    Java8:  2016-01-01T00:00-06:00
    jodaMillis:1451628000000 == javaMillis:1451628000000

    candidate:  "2016-11"
    Joda:   2016-11-01T00:00:00.000-05:00
    Java8:  2016-11-01T00:00-06:00
    jodaMillis:1477976400000 != javaMillis:1477980000000

    candidate:  "2016-11-21"
    Joda:   2016-11-21T00:00:00.000-06:00
    Java8:  2016-11-21T00:00-06:00
    jodaMillis:1479708000000 == javaMillis:1479708000000

    candidate:  "2016-11-21T01"
    Joda:   2016-11-21T01:00:00.000-06:00
    Java8:  2016-11-21T01:00-06:00
    jodaMillis:1479711600000 == javaMillis:1479711600000

    candidate:  "2016-11-21T01:02"
    Joda:   2016-11-21T01:02:00.000-06:00
    Java8:  2016-11-21T01:02-06:00
    jodaMillis:1479711720000 == javaMillis:1479711720000

    candidate:  "2016-11-21T01:02:03"
    Joda:   2016-11-21T01:02:03.000-06:00
    Java8:  2016-11-21T01:02:03-06:00
    jodaMillis:1479711723000 == javaMillis:1479711723000
like image 138
s7vr Avatar answered Oct 30 '22 19:10

s7vr

This will parse all of your dates except the somewhat funky 2016-11-21T01. If you really need that have a look at the way DateTimeFormatterBuilder is constructing the ISO_TIME formatter. It uses an optional seconds field. Copy it and make the minutes field optional too. 

DateTimeFormatter isoDateParser = new DateTimeFormatterBuilder()
        .parseCaseInsensitive()
        .append(DateTimeFormatter.ISO_LOCAL_DATE)
        .optionalStart()
        .appendLiteral('T')
        .append(DateTimeFormatter.ISO_TIME)
        .toFormatter();
like image 37
teppic Avatar answered Oct 30 '22 19:10

teppic

DateTimeFormatter is your class. However, it takes some getting used to this new java.time package. I worked with it and after a while I found it very flexible and powerful. I wrote a little article where I described a general idea on how to attempt to parse a String of unknown format to a Date. Here is the link: Java 8 java.time package: parsing any string to date

like image 31
Michael Gantman Avatar answered Oct 30 '22 18:10

Michael Gantman
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