Is there any way to map MySql TIMESTAMP to java.lang.Long?

Question

So I have this object saved to the database with one property being dateCreated which is, of course, saved as MySQL timestamp. But while sending the data to the client, I want to be in milliseconds. Right now, I've mapped it to the Date object and converting it to milliseconds further. But I thought, what if I could map my POJO in such a way that it retrieves values in milliseconds. Here is what I've tried.

OmsJob:

@Entity
@EntityListeners(PreventAnyUpdate.class)
@ConfigurationProperties("omsjob")
@Table(name = "OMSJob")
public class OmsJob {

    @Id
    @NotNull
    @Column(name = "jobId")
    private String id;

    @NotNull
    private Long dateCreated; // If I map this property to Date, it works fine

}

I thought I'll add a custom converter that'll convert java.util.Date or java.sql.Date to milliseconds. But it isn't working:

@Component
@ConfigurationPropertiesBinding
public class DateConverter implements Converter<Date, Long> {

    @Override
    public Long convert(Date date) {
        return date.getTime();
    }
}

The error I am getting is pretty obvious but is there any way to achieve what I am trying to?

ERROR 229770 --- [           main] o.h.engine.jdbc.spi.SqlExceptionHelper   : Unsupported conversion from TIMESTAMP to java.lang.Long

Answer 1

An attribute won't know about its converter until you declare it. Do it as follows:

@NotNull
@Convert (converter = DateConverter.class)
private Long dateCreated;

Also, change the converter as follows:

public class DateConverter implements AttributeConverter<Date, Long> {

    @Override
    public Date convertToDatabaseColumn(Long millis) {
        retrun new Date(millis);
    }

    @Override
    public Long convertToEntityAttribute(Date date) {
        return date.getTime();
    }
}