如何使用JPA在Java中将MySQL时间戳字段保留为长（纪元）字段？

Question

I have a column in a MySQL table like:

createdAt timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP`.

I want it to be stored in a field like:

private Long createdAt;

How would I do this?

Answer 1

Best if you use the supported types in TemporalType enum. Longs would require a converter.

Here's a converter for longs:

import java.sql.Timestamp;

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

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

   @Override
   public Timestamp convertToDatabaseColumn(Long attribute) {
      if (attribute == null)
         return null;
      return new Timestamp(attribute);
   }

   @Override
   public Long convertToEntityAttribute(Timestamp dbData) {
      if (dbData == null)
         return null;
      return dbData.getTime();

   }

}

Answer 2

简单地使用@Temporal(TemporalType.TIMESTAMP)以上createdAt