如何将休眠时间戳映射到MySQL BIGINT？

I am using Hibernate 3.x, MySQL 4.1.20 with Java 1.6. I am mapping a Hibernate Timestamp to a MySQL TIMESTAMP. So far so good. The problem is that MySQL stores the TIMESTAMP in seconds and discards the milliseconds and I now need millisecond precision. I figure I can use a BIGINT instead of TIMESTAMP in my table and convert the types in my Java code. I'm trying to figure out if there is a better way of doing this using hibernate, mysql, JDBC or some combination so I can still use date functions in my HSQL and/or SQL queries?

我正在使用Hibernate 3.x,MySQL 4.1.20和Java 1.6。我正在将Hibernate Timestamp映射到MySQL TIMESTAMP。到现在为止还挺好。问题是MySQL以秒为单位存储TIMESTAMP并丢弃毫秒,现在我需要毫秒精度。我想我可以在我的表中使用BIGINT而不是TIMESTAMP并转换我的Java代码中的类型。我试图弄清楚是否有更好的方法使用hibernate,mysql,JDBC或某种组合这样做,所以我仍然可以在我的HSQL和/或SQL查询中使用日期函数?

4 个解决方案

#1

Also, look at creating a custom Hibernate Type implementation. Something along the lines of (psuedocode as I don't have a handy environment to make it bulletproof):

另外,请看创建自定义Hibernate Type实现。 (psuedocode,因为我没有一个方便的环境,使其防弹):

public class CalendarBigIntType extends org.hibernate.type.CalendarType {
    public Object get(ResultSet rs, String name) {
        return cal = new GregorianCalendar(rs.getLong(name));
    }
    public void set(PreparedStatement stmt, Object value, int index) {
        stmt.setParameter(index, ((Calendar) value).getTime());
    }
}

Then, you'll need to map your new object using a hibernate TypeDef and Type mappings. If you are using Hibernate annotations, it be along the lines of:

然后,您需要使用hibernate TypeDef和Type映射来映射新对象。如果您正在使用Hibernate注释,它将遵循以下方式:

@TypeDef (name="bigIntCalendar", typeClass=CalendarBigIntType.class)
@Entity
public class MyEntity {
    @Type(type="bigIntCalendar")
    private Calendar myDate;
}

4 个解决方案

#1

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