I have a SpringBoot app. using Spring Initializer, embedded Tomcat, Thymeleaf template engine, and package as an executable JAR file.
I have a domain object with 2 properties (initDate, endDate). I want to create 2 converters to deal with mySQL DB
@Convert(converter = LocalDateTimeAttributeConverter.class)
private LocalDateTime initDate;
@Convert(converter = ZonedDateTimeAttributeConverter.class)
private ZonedDateTime endDate;
the converter 1 (is OK)
@Converter
public class LocalDateTimeAttributeConverter implements AttributeConverter<LocalDateTime, Timestamp> {
@Override
public Timestamp convertToDatabaseColumn(LocalDateTime localDateTime) {
return (localDateTime == null ? null : Timestamp.valueOf(localDateTime));
}
@Override
public LocalDateTime convertToEntityAttribute(Timestamp sqlTimestamp) {
return (sqlTimestamp == null ? null : sqlTimestamp.toLocalDateTime());
}
}
This is the one that I want to create
@Converter
public class ZonedDateTimeAttributeConverter implements AttributeConverter<ZonedDateTime, Timestamp> {
@Override
public Timestamp convertToDatabaseColumn(ZonedDateTime zoneDateTime) {
return (zoneDateTime == null ? null : Timestamp.valueOf(zoneDateTime));
}
@Override
public ZonedDateTime convertToEntityAttribute(Timestamp sqlTimestamp) {
return (sqlTimestamp == null ? null : sqlTimestamp.toZonedDateTime());
}
}
But I can't because I have 2 errors:
The method valueOf(String) in the type Timestamp is not applicable for the arguments (ZonedDateTime)
and the TimeStamp does not have the method toZonedDateTime()
and if I don't add any converter for the ZonedDate, JPA creates a table with the type varbinary(255)
Timestamp extends
Date
to provide nanosecond accuracy. NeitherDate
norTimestamp
are designed to refer to a specific timezone asZoneDateTime
.If you need to convert
ZonedDateTime
->Timestamp
you will have to discard the timezone/offset information. E.g.and for converting
Timestamp
->ZonedDateTime
you need to specify an offset:or timezone:
If your intention is to save
ZonedDateTime
variables in the database and preserve the various timezones specified there, I recommend designing your database accordingly. Suggestions:DATETIME
to save aLocalDateTime
and aVARCHAR
saving a timezone like"Europe/Paris"
or aSMALLINT
saving an offset in minutes.ZonedDateTime
to aString
and save in aVARCHAR
column like"2017-05-16T14:12:48.983682+01:00[Europe/London]"
. You'll then have to parse it when reading from the database.Jon Skeet said it already:
Jon also asked the good question, which time zone do you want? I have guessed at
ZoneId.systemDefault()
. Obviously a different time zone will give a different result, so I hope you will think twice and will be able to find the right time zone for your purpose.PS I have reduced the usage of parentheses since I found it more readable with fewer. You can add them back in if you prefer.