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hibernate处置多表连接查询

发布时间: 2012-09-03 09:48:39 作者: rapoo

hibernate处理多表连接查询
如果我们在Hibernate中需要查询多个表的不同字段,那么如何来获取Hibernate多表查询的结果呢?有两种方式: 对各个字段分别转化成对应类型;构造自己的复合类型。

如果我们在Hibernate中需要查询多个表的不同字段,那么如何来获取Hibernate多表查询的结果呢?有两种方式:

1、 对各个字段分别转化成对应类型,如下:

Java代码:

1. Query q = session.createQuery(" select members, classInfo.className " +
2. " from Members members, ClassInfo classInfo " +
3. " where members.level = classInfo.classCode ");
4. List result = q.list();
5. Iterator it = result.iterator();
6. while (it.hasNext()) {
7. Object[] tuple = (Object[]) it.next();
8. Members members = (Members) tuple[ 0 ];
9. String className = (String) tuple[ 1 ];
10. }
11. Query q = session.createQuery
12. (" select members, classInfo.className " +
13. " from Members members, ClassInfo classInfo " +
14. " where members.level = classInfo.classCode ");
15. List result = q.list(); Iterator it = result.iterator();
16. while (it.hasNext()) { Object[] tuple = (Object[]) it.next();
17. Members members = (Members) tuple[ 0 ];
18. String className = (String) tuple[ 1 ]; }

这是获取Hibernate多表查询的结果的最常用的方式。

2、构造自己的复合类型,如下:

Java代码:

1. Query q = session.createQuery
2. (" select new NewMembers(members, classInfo.className) " +
3. " from Members members, ClassInfo classInfo " +
4. " where members.level = classInfo.classCode ");
5. Query q = session.createQuery
6. (" select new NewMembers(members, classInfo.className)
7. " + " from Members members, ClassInfo classInfo " + "
8. where members.level = classInfo.classCode ");

当然我们需要有一个NewMembers类和相应的构造方式。以上便是两种用于获取Hibernate多表查询的结果的方法以及其相应的代码。

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