在龙目岛漂亮打印日历

Question

I use lombok and it it is really great! However if I print beans that contain Calendar properties it prints the Calendar object (of course...) and it is really confusing to see the value of the Calendar. I can see something like

ScheduledEvent(id=1, scheduledStartDate=java.util.GregorianCalendar[time=1492032183000,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Europe/Budapest",offset=3600000,dstSavings=3600000,useDaylight=true,transitions=151,lastRule=java.util.SimpleTimeZone[id=Europe/Budapest,offset=3600000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=2,startMonth=2,startDay=-1,startDayOfWeek=1,startTime=3600000,startTimeMode=2,endMode=2,endMonth=9,endDay=-1,endDayOfWeek=1,endTime=3600000,endTimeMode=2]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2017,MONTH=3,WEEK_OF_YEAR=15,WEEK_OF_MONTH=3,DAY_OF_MONTH=12,DAY_OF_YEAR=102,DAY_OF_WEEK=4,DAY_OF_WEEK_IN_MONTH=2,AM_PM=1,HOUR=11,HOUR_OF_DAY=23,MINUTE=23,SECOND=3,MILLISECOND=0,ZONE_OFFSET=3600000,DST_OFFSET=3600000], ...

Is it possible to assign a SimpleDateFormat to the Calendar somehow (eg if lombok meets the Calendar object then uses this formatter) and having a simple value like '2016-34-34T12:12:12.543'?

Thanks,
V.

Answer 1

This is not specific to lombok but rather the toString() implementation of GregorianCalendar .

If you want to do anything about it you have several options:

• use LocalDateTime or any of the new Time API classes which also have a more beautiful toString() output
• wrap GregorianCalendar -instances in objects of your own and implement toString() of that wrapper class yourself
• don't let lombok generate toString() for ScheduledEvent but rather provide your own implementation
• modify lombok to handle GregorianCalendar the way you like

Answer 2

I know this post is two years ago but now there is a better soluce.

Let lombok generate the toString() method, annotade your field with @ToString.Exclude and create a method with this annotation: @ToString.Include(name = "yourVariable") .

Here is an example:

@Data
public class ScheduledEvent {
    private int id;

    @ToString.Exclude
    private GregorianCalendar scheduledStartDate;
    // etc ...

    @ToString.Include(name = "scheduledStartDate")
    private String formatScheduledStartDate() {
        return new SimpleDateFormat("yyyy-MM-dd").format(scheduledStartDate.getTime());
    }
}

And the toString() method returns in this case:

ScheduledEvent(id=1, scheduledStartDate=2019-03-04)