Unsupported conversion from DATE to java.lang.Integer

Question

So, I have the following model generated using Java Ebean library:

package models;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import java.time.LocalDateTime;

@Entity
@Table(name = "Zeit")
public class Zeit extends BaseModel {

    @Column
    private LocalDateTime start;

    @Column
    private LocalDateTime ende;

    @Column
    private int pause;

    @ManyToOne(optional = false)
    private Benutzer benutzer;

    @Column
    private LocalDateTime pauseStart;

    public Zeit() {
    }

    public Zeit(LocalDateTime start, LocalDateTime ende, int pause, LocalDateTime pauseStart) {
        this.start = start;
        this.ende = ende;
        this.pause = pause;
        this.pauseStart = pauseStart;
    }

    public LocalDateTime getStart() {
        return start;
    }

    public void setStart(LocalDateTime start) {
        this.start = start;
    }

    public LocalDateTime getEnde() {
        return ende;
    }

    public void setEnde(LocalDateTime ende) {
        this.ende = ende;
    }

    public int getPause() {
        return pause;
    }

    public void setPause(int pause) {
        this.pause = pause;
    }

    public Benutzer getBenutzer() {
        return benutzer;
    }

    public void setBenutzer(Benutzer benutzer) {
        this.benutzer = benutzer;
    }

    public LocalDateTime getPauseStart() {
        return pauseStart;
    }

    public void setPauseStart(LocalDateTime pauseStart) {
        this.pauseStart = pauseStart;
    }
}

which results in these SQL statements:

create table zeit (
  id                            bigint auto_increment not null,
  start                         datetime(6),
  ende                          datetime(6),
  pause                         integer not null,
  version                       bigint not null,
  when_created                  datetime(6) not null,
  when_modified                 datetime(6) not null,
  constraint pk_zeit primary key (id)
);

The idea is that I want to write down the opening and closing time into the db. This is basically possible by using

private void btn_anmeldenActionPerformed(java.awt.event.ActionEvent evt) {
    try {
        Zeit z = new Zeit();
        z.setStart(LocalDateTime.now());
        z.setBenutzer(benutzer);
        z.save();
        btn_anmelden.setText(String.valueOf(z.getStart()));
        btn_anmelden.setEnabled(false);
    } catch (Exception e) {

    }
}

But when getting the entity back from the database using the following:

private void initState() {
    Zeit lastTime = new QZeit().findList().get(0);

    System.out.println(lastTime);
}

I get the error:

com.mysql.cj.exceptions.DataConversionException: Unsupported conversion from TIMESTAMP to java.lang.Integer

So far I tried to

• change different data types in the database
• use different types in my code ( java.util.Date , java.sql.Date , ...)

I'm also using

• mysql-connector-java : 8.0.19
• io.ebean :12.1.8

Answer 1

Wrong data type

The DATETIME data type in MySQL represents a date and a time-of-day but lacks any concept of time zone or offset. So this type cannot represent a moment, is not a point on the timeline.

The standard SQL equivalent of this type is TIMESTAMP WITHOUT TIME ZONE . The equivalent in Java is LocalDateTime .

To record a moment in standard SQL, use TIMESTAMP WITH TIME ZONE . In MySQL, TIMESTAMP . In Java, Instant , OffsetDateTime , and ZonedDateTime , with support for OffsetDateTime being required for JDBC 4.2 and later while support for the other two is optional.

OffsetDateTime odt = OffsetDateTime.now() ;
myPreparedStatement.setObject( … , odt ) ;  // Writing to a column of MySQL type `TIMESTAMP`, standard SQL `TIMESTAMP WIH TIME ZONE`.

Retrieval.

OffsetDateTime odt = myResultSet.getObject( … , OffsetDateTime.class ) ;

As for the ebean error, you've not provided enough detail. We would need to see the Java class into which it is trying to instantiate.