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锁定老帖子 主题：使用UserType来持久化复合类型属性
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发表时间：2004-11-23
偶们经常会遇到一些用户需求, 需要实现一个区间类型的东东:
public class Entity { private Date startDate; private Date endDate; private ......; } 如项目的开始/结束时间, 人员的任职期间等等 但是如要比较这个对象和其他对象区间的关系, 就得写一些恶心的code: if(this.startDate > that.startDate && this.endDate < that.endDate) if(this.startDate < that.startDate) ...... 一堆的if else了. 或许你会觉得这些小东西这样写就可以了, 但是为了有一个更完美, 更好用的Domain Object, 是值得偶们在这些小细节上操劳的. 有一些现成的lib就是做这些东西的, 比如: http://timeandmoney.sourceforge.net/ http://joda-time.sourceforge.net/ 这里用timeandmoney lib为例子, 来介绍一下利用Hibernate的UserType来创建一个Domain Object 首先是一个业务对象:
import com.domainlanguage.time.TimeInterval;
public class RecordLog extends Entity {
private String description;
private TimeInterval interval;
//getters and setters......
}
然后是mapping文件:
<class name="RecordLog">
<id name="id">
<generator class="native"/>
</id>
<property name="description"/>
<property name="interval" type="TimeIntervalType">
<column name="LOWER_LIMIT"/>
<column name="INCLUDES_LOWER_LIMIT"/>
<column name="UPPER_LIMIT"/>
<column name="INCLUDES_UPPER_LIMIT"/>
</property>
</class>
一个操作它的Manager:
public class Manager extends HibernateDaoSupport {
public RecordLog load(Long id); {
return (RecordLog); getHibernateTemplate();.load(RecordLog.class, id);;
}
public void save(RecordLog log); {
getHibernateTemplate();.saveOrUpdate(log);;
}
}
偶们先来看看它是怎么运行的:
public void test(); {
TimePoint nov01 = TimePoint.atMidnightGMT(2004, 11, 01);;
TimePoint nov03 = TimePoint.atMidnightGMT(2004, 11, 03);;
TimePoint nov02 = TimePoint.atMidnightGMT(2004, 11, 02);;
TimePoint nov05 = TimePoint.atMidnightGMT(2004, 11, 05);;
RecordLog log1 = new RecordLog();;
log1.setDescription("Record Log 1");;
log1.setInterval(TimeInterval.closed(nov01, nov03););;
RecordLog log2 = new RecordLog();;
log2.setDescription("Record Log 2");;
log2.setInterval(TimeInterval.closed(nov02, nov05););;
//这里, 偶们只取交叉区间
//比原来的一堆if else简洁多了吧?
if(log1.getInterval();.intersects(log2.getInterval();););{
log1.setInterval(log1.getInterval();.intersect(log2.getInterval();););;
}
manager.save(log1);;
RecordLog loaded = manager.load(log1.getId(););;
assertEquals("Record Log 1", loaded.getDescription(););;
assertEquals(nov02, loaded.getInterval();.lowerLimit(););;
assertEquals(nov03, loaded.getInterval();.upperLimit(););;
assertTrue(loaded.getInterval();.includesLowerLimit(););;
assertTrue(loaded.getInterval();.includesUpperLimit(););;
}
怎么样, 是不是比原来的代码简单多了? 在背后干脏活,累活的就是这个TimeIntervalType和TimeAndMoney Lib: 代码格式好难看阿, 只好用quote 写道 public class TimeIntervalType implements UserType { private static final int[] SQL_TYPES = new int[] { Hibernate.TIMESTAMP.sqlType(), Hibernate.BOOLEAN.sqlType(), Hibernate.TIMESTAMP.sqlType(), Hibernate.BOOLEAN.sqlType() }; public int[] sqlTypes() { return SQL_TYPES; } public Class returnedClass() { return TimeInterval.class; } public boolean equals(Object x, Object y) throws HibernateException { if (x == y) return true; if (x == null || y == null) return false; return ((TimeInterval) x).compareTo((TimeInterval) y) == 0; } public Object nullSafeGet(ResultSet rs, String[] names, Object owner) throws HibernateException, SQLException { TimePoint lower = TimePoint.from((Timestamp) Hibernate.TIMESTAMP.nullSafeGet(rs, names[0])); boolean lowerIncluded = ((Boolean) Hibernate.BOOLEAN.nullSafeGet(rs, names[1])).booleanValue(); TimePoint upper = TimePoint.from((Timestamp) Hibernate.TIMESTAMP.nullSafeGet(rs, names[2])); boolean upperIncluded = ((Boolean) Hibernate.BOOLEAN.nullSafeGet(rs, names[3])).booleanValue(); return new TimeInterval(lower, lowerIncluded, upper, upperIncluded); } public void nullSafeSet(PreparedStatement st, Object value, int index) throws HibernateException, SQLException { TimeInterval interval = (TimeInterval) value; Hibernate.TIMESTAMP.nullSafeSet(st, new Timestamp(((TimePoint) interval.lowerLimit()).asJavaUtilDate().getTime()), index); Hibernate.BOOLEAN.nullSafeSet(st, new Boolean(interval.includesLowerLimit()), index + 1); Hibernate.TIMESTAMP.nullSafeSet(st, new Timestamp(((TimePoint) interval.upperLimit()).asJavaUtilDate().getTime()), index + 2); Hibernate.BOOLEAN.nullSafeSet(st, new Boolean(interval.includesUpperLimit()), index + 3); } public Object deepCopy(Object value) throws HibernateException { if (value == null) return null; TimeInterval interval = (TimeInterval) value; return new TimeInterval((TimePoint) interval.lowerLimit(), interval.includesLowerLimit(), (TimePoint) interval.upperLimit(), interval .includesUpperLimit()); } public boolean isMutable() { return true; } } 声明：ITeye文章版权属于作者，受法律保护。没有作者书面许可不得转载。
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发表时间：2004-11-24
不好意思，今天才看到。
很好的UserType教材， 非常经典。 看了这文章后，我就明白了什么是UserType以及UserType如何定义和操作。 单这个问题本身，我认为用组件解决起来可能会更加简单，最多继承一下TimeInterval。 |
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