Hibernate CompositeUserType，可在JPA-QL（或HQL）查询中进行比较

Question

我为Hibernate创建了一个自定义类型来存储OffsetDateTime的时间戳和偏移量（因为默认的JPA 2.2/Hibernate 5.2 with java 8支持实现会丢失偏移量信息）：

public class OffsetDateTimeHibernateType implements CompositeUserType {

    @Override
    public Class returnedClass() {
        return OffsetDateTime.class;
    }

    @Override
    public String[] getPropertyNames() {
        return new String[] {"dateTime", "zoneOffset"};
    }

    @Override
    public Type[] getPropertyTypes() {
        // Not sure if we should use LocalDateTimeType.INSTANCE instead of TIMESTAMP
        return new Type[]{StandardBasicTypes.TIMESTAMP, StandardBasicTypes.INTEGER};
    }

    @Override
    public Object getPropertyValue(Object o, int propertyIndex) {
        if (o == null) {
            return null;
        }
        OffsetDateTime offsetDateTime = (OffsetDateTime) o;
        switch (propertyIndex) {
            case 0:
                return Timestamp.valueOf(offsetDateTime.toLocalDateTime());
            case 1:
                return offsetDateTime.getOffset().getTotalSeconds();
            default:
                throw new IllegalArgumentException("The propertyIndex (" + propertyIndex
                        + ") must be 0 or 1.");
        }
    }

    @Override
    public OffsetDateTime nullSafeGet(ResultSet resultSet, String[] names, SessionImplementor session, Object owner)
            throws SQLException {
        if (resultSet == null) {
            return null;
        }
        Timestamp timestamp = (Timestamp) StandardBasicTypes.TIMESTAMP.nullSafeGet(resultSet, names[0], session, owner);
        if (timestamp == null) {
            throw new IllegalStateException("The timestamp (" + timestamp + ") for an "
                    + OffsetDateTime.class.getSimpleName() + "cannot be null.");
        }
        LocalDateTime localDateTime = timestamp.toLocalDateTime();
        Integer zoneOffsetSeconds = (Integer) StandardBasicTypes.INTEGER.nullSafeGet(resultSet, names[1], session, owner);
        if (zoneOffsetSeconds == null) {
            throw new IllegalStateException("The zoneOffsetSeconds (" + zoneOffsetSeconds + ") for an "
                    + OffsetDateTime.class.getSimpleName() + "cannot be null.");
        }
        return OffsetDateTime.of(localDateTime, ZoneOffset.ofTotalSeconds(zoneOffsetSeconds));
    }

    @Override
    public void nullSafeSet(PreparedStatement statement, Object value, int parameterIndex, SessionImplementor session)
            throws SQLException {
        if (value == null) {
            statement.setNull(parameterIndex, StandardBasicTypes.TIMESTAMP.sqlType());
            statement.setNull(parameterIndex, StandardBasicTypes.INTEGER.sqlType());
            return;
        }
        OffsetDateTime offsetDateTime = (OffsetDateTime) value;
        statement.setTimestamp(parameterIndex, Timestamp.valueOf(offsetDateTime.toLocalDateTime()));
        statement.setInt(parameterIndex, offsetDateTime.getOffset().getTotalSeconds());
    }

    // ************************************************************************
    // Mutable related methods
    // ************************************************************************

    @Override
    public boolean isMutable() {
        return false;
    }

    @Override
    public Object deepCopy(Object value) {
        return value; // OffsetDateTime is immutable
    }

    @Override
    public Object replace(Object original, Object target, SessionImplementor session, Object owner) {
        return original; // OffsetDateTime is immutable
    }

    @Override
    public void setPropertyValue(Object component, int property, Object value) {
        throw new UnsupportedOperationException("A OffsetDateTime is immutable.");
    }

    // ************************************************************************
    // Other methods
    // ************************************************************************

    @Override
    public boolean equals(Object a, Object b) {
        if (a == b) {
            return true;
        } else if (a == null || b == null) {
            return false;
        }
        return a.equals(b);
    }

    @Override
    public int hashCode(Object o) {
        if (o == null) {
            return 0;
        }
        return o.hashCode();
    }

    @Override
    public Serializable disassemble(Object value, SessionImplementor session) {
        return (Serializable) value;
    }

    @Override
    public Object assemble(Serializable cached, SessionImplementor session, Object owner) {
        return cached;
    }

}

现在，我想比较一下，所以这个JPA-QL查询可以工作：

       @NamedQuery(name = "Shift.myQuery",
                   query = "select sa from Shift sa" +
                           " where sa.endDateTime >= :startDateTime" +
                           " and sa.startDateTime < :endDateTime")

在这个模型上：

@Entity
public class Shift {

    @Type(type = "...OffsetDateTimeHibernateType")
    @Columns(columns = {@Column(name = "startDateTime"), @Column(name="startDateTimeOffset")})
    private OffsetDateTime startDateTime;
    @Type(type = "...OffsetDateTimeHibernateType")
    @Columns(columns = {@Column(name = "endDateTime"), @Column(name="endDateTimeOffset")})
    private OffsetDateTime endDateTime;

    ...

}

但这在以下方面失败了：

HHH000177: Error in named query: Shift.myQuery: org.hibernate.hql.internal.ast.QuerySyntaxException: >= operator not supported on composite types. [select sa from org.optaplanner.openshift.employeerostering.shared.shift.Shift sa where sa.endDateTime >= :startDateTime and sa.startDateTime < :endDateTime]
    at org.hibernate.hql.internal.ast.QuerySyntaxException.generateQueryException(QuerySyntaxException.java:79)
    at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:103)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:218)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:142)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:115)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:76)
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:150)
    at org.hibernate.internal.NamedQueryRepository.checkNamedQueries(NamedQueryRepository.java:155)
    at org.hibernate.internal.SessionFactoryImpl.checkNamedQueries(SessionFactoryImpl.java:796)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:492)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:422)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:880)

如何使CustomUserType具有可比性？

Answer 1

Hibernate无法知道如何将自定义类型与多个列进行比较。您知道列之间的关系，但Hibernate不知道。在没有进行测试的情况下（如果我稍后有时间，可以这样做），我认为您可以重写查询以使用部件的属性名称，例如：

select sa from Shift sa
  where sa.endDateTime.dateTime >= :startDateTimeDateTimePart
  and sa.startDateTime.dateTime < :endDateTimeDateTimePart

要使其与偏移量一起工作，您需要规范化您比较的值，即将偏移量表示的小时数添加到日期。您可以使用数据库的自定义函数来做到这一点，请参阅JPA 2.2（https://jcp.org/aboutJava/communityprocess/mrel/jsr338/index.html）中的4.6.17.3。当然，您也可以在数据库中定义一个自定义比较函数，它将两个部分都作为输入参数并使用该函数调用它，但就我个人而言，我会尽可能地坚持预定义的函数。无论您使用什么数据库，都应该涵盖向时间戳添加小时。