问如何将Vaadin DateField绑定到LocalDateTime

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package de.company.project.portal.application.views.documents;

import com.vaadin.data.Converter;
import com.vaadin.data.Result;
import com.vaadin.data.ValueContext;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Objects;

/**
 * A converter that converts between <code>LocalDate</code> and
 * <code>LocalDateTime</code>.
 *
 * Created from Vaadin v.8.13.0 LocalDateTimeToDateConverter
 */
public class LocalDateToLocalDateTimeConverter
        implements Converter<LocalDate, LocalDateTime>
{
    private ZoneId zoneId;

    /**
     * Creates a new converter using the given time zone.
     *
     * @param zoneId
     *            the time zone to use, not <code>null</code>
     */
    public LocalDateToLocalDateTimeConverter(ZoneId zoneId) {
        this.zoneId = Objects.requireNonNull(zoneId,
                "Zone identifier cannot be null");
    }


    @Override
    /** @return LocalDateTime from LocalDate with atTime(0,0,0,0) */
    public Result<LocalDateTime> convertToModel(LocalDate localDate,
                                                ValueContext context)
    {
        if (localDate == null) {
            return Result.ok(null);
        }
        return Result.ok(LocalDateTime.from(localDate.atTime(0,0,0,0))); //(hrs, mins, sec, nano sec)
    }


    @Override
    public LocalDate convertToPresentation(LocalDateTime localDateTime,
                                           ValueContext context)
    {
        if (localDateTime == null) {
            return null;
        }
        return LocalDate.from(localDateTime.atZone(zoneId));
    }

}

public void bindCreationDate(DateField field) {
    forField(field.getField())
            .withConverter(new LocalDateToLocalDateTimeConverter(ZoneId.systemDefault()))
            .bind(DocumentDto::getCreationDate, DocumentDto::setCreationDate);
}