Question

我正在密切关注这些帖子（https://www.thoughts-on-java.org/persist-localdate-localdatetime-jpa/，https://github.com/lbtc-xxx/jpa21converter）以实现从JPA 2.1 sql.Timestamp到LocalDateTime的转换器，反之亦然。

然而，看起来我的召唤器不起作用。它似乎永远不会被调用，因为sysout不打印任何东西。

这是我的转换器：

import java.sql.Timestamp;
import java.time.LocalDateTime;

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;

@Converter(autoApply = true)
public class LocalDateTimeConverter implements AttributeConverter<LocalDateTime, Timestamp>{

    @Override
    public Timestamp convertToDatabaseColumn(LocalDateTime localDateTime) {
        System.out.println("CONVERTER TIMESTAMPS: " + localDateTime);
        return (localDateTime == null ? null : Timestamp.valueOf(localDateTime));
    }

    @Override
    public LocalDateTime convertToEntityAttribute(Timestamp timestamp) {
        System.out.println("CONVERTER TIMESTAMPS: " + timestamp);
        return (timestamp == null ? null : timestamp.toLocalDateTime());
    }

}

这是实体类

@Entity
@Table(name = "survey")
public class Question {
    @Id
    @GeneratedValue(strategy = Generationtype.AUTO)
    private Integer id;
    ...
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    /*I also tried here: @Convert(converter = LocalDateTimeConverter.class))*/
    private LocalDateTime createdAt;
    ...
}

这是我在DAO课程中的方法：

TypedQuery<Question> query = em.createQuery("SELECT q FROM Question q", Question.class);
query.getResultList().forEach(question -> {
    LOGGER.info("{}|{}|{}", question.getId(), question.getDescription(), question.getCreatedAt());
});

return query.getResultList();

打印出来：

1|hello|null
2|hi|null
3|howdy|null

提前谢谢。

Answer 1

我现在就开始工作了。我删除了

瞬态

这

private transient LocalDateTime createdAt;

SonarLint要求它，因为该类实现了Serializable，这就是为什么我把它放在首位。

LocalDateTime的JPA AttributeConverter

1 个答案: