Hibernate自定义UserType不起作用

Question

我已经创建了一个UserType(见下文)来处理我们的mySQL数据库中的情况,我们一直在将空日期保存为0000-00-00 00:00:00.

当我尝试使用null为dispDT持久保存我的实体时(见下文),它会生成此异常:"javax.persistence.PersistenceException:org.hibernate.PropertyValueException:not-null属性引用null或transient值:myEntity.dispDt"

通过在MySQLTimeStampUserType中的每个方法中设置断点,我可以看到它调用deepCopy方法并且从不调用nullSafeSet方法.我认为nuyllSafeSet方法的重点是允许我在持久化之前操纵该值.我究竟做错了什么？

实体注释

@Basic(optional = false)
@Column(name = "disp_dt")
@Type(type = "mypackage.MySQLTimeStampUserType")
//    @Temporal(TemporalType.TIMESTAMP)
private Date dispDt;

用户类型类

public class MySQLTimeStampUserType implements UserType {

private static final int[] SQL_TYPES = {Types.TIMESTAMP};

public int[] sqlTypes() {
    return SQL_TYPES;
}

public Class returnedClass() {
    return Date.class;
}

public boolean equals(Object x, Object y) throws HibernateException {
    if (x == y) {
        return true;
    } else if (x == null || y == null) {
        return false;
    } else {
        return x.equals(y);
    }

}

public int hashCode(Object arg0) throws HibernateException {
    throw new UnsupportedOperationException("Not supported yet.");
}

public Object nullSafeGet(ResultSet resultSet, String[] names, Object owner) throws HibernateException, SQLException {
    // if the date is 0000-00-00 00:00:00 return null, else return the timestamp
    Date result = null;
    if (!resultSet.wasNull()) {
        if (!resultSet.getString(names[0]).equals("0000-00-00 00:00:00")) {
            result = resultSet.getDate(names[0]);
        }
    }
    return result;
}

public void nullSafeSet(PreparedStatement statement, Object value, int index) throws HibernateException, SQLException {
    // if the date is null set the value to "0000-00-00 00:00:00" else save the timestamp
    if (value == null) {
        statement.setString(index, "0000-00-00 00:00:00");
    } else {
        statement.setTimestamp(index,(Timestamp) value);
    }

}

public Object deepCopy(Object value) throws HibernateException {
    return value;
}

public boolean isMutable() {
    return false;
}

public Serializable disassemble(Object value) throws HibernateException {
    throw new UnsupportedOperationException("Not supported yet.");
}

public Object assemble(Serializable cached, Object owner) throws HibernateException {
    throw new UnsupportedOperationException("Not supported yet.");
}

public Object replace(Object original, Object target, Object owner) throws HibernateException {
    return original;
}
}

Answer 1

这些细微差别在这里得到了很好的讨论:http: //blog.xebia.com/2009/11/09/understanding-and-writing-hibernate-user-types/

Answer 2

您的问题不在于您的 UserType - 问题在于您已将属性声明为非空（使用@Basic option="false"），但您将其设置为 null。

也就是说，我会小心地返回 deepCopy / assemble / disassemble 方法中的原始值。java.util.Date是可变的，您可能会在那里自找麻烦。