hibernate3学习笔记(七)｜Criteria Queries

 仍然接着前面的例子来讲：http://blog.csdn.net/kunshan_shenbin/archive/2008/09/02/2864883.aspx

示例代码如下：

1. package com.hb3.pack_01;
3. import java.util.Iterator;
4. import java.util.List;
6. import org.hibernate.Criteria;
7. import org.hibernate.Hibernate;
8. import org.hibernate.Session;
9. import org.hibernate.SessionFactory;
10. import org.hibernate.cfg.Configuration;
11. import org.hibernate.criterion.Example;
12. import org.hibernate.criterion.Order;
13. import org.hibernate.criterion.ProjectionList;
14. import org.hibernate.criterion.Projections;
15. import org.hibernate.criterion.Property;
16. import org.hibernate.criterion.Restrictions;
17. import org.hibernate.type.Type;
19. import com.hb3.pack_01.model.User;
21. public class BusinessService {
23.     public static void main(String[] args) {
24.         
25.         Configuration config = new Configuration().configure();
26.         SessionFactory sessionFactory = config.buildSessionFactory();      
27.         Session session = sessionFactory.openSession();
28.         
29.         Criteria criteria = session.createCriteria(User.class);
30.         criteria.addOrder(Order.asc("age"));
31.         List users = criteria.list();
32.         printUserInfo(users);
33.         
34.         criteria = session.createCriteria(User.class);
35.         criteria.add(Restrictions.gt("age", new Integer(22)));
36.         criteria.add(Restrictions.lt("age", new Integer(27)));
37.         users = criteria.list();
38.         printUserInfo(users);
39.         
40.         criteria = session.createCriteria(User.class);
41.         criteria.add(Restrictions.or( 
42.                         Restrictions.eq("age", new Integer(23)), 
43.                         Restrictions.isNull("age") 
44.                     )); 
45.         users = criteria.list();
46.         printUserInfo(users);
47.         
48.         criteria = session.createCriteria(User.class);
49.         criteria.add(Restrictions.sqlRestriction("{alias}.name LIKE (?)", "%ya%", Hibernate.STRING));
50.         users = criteria.list();
51.         printUserInfo(users);
52.         
53.         criteria = session.createCriteria(User.class);
54.         Integer[] ages = {new Integer(26), new Integer(28)};
55.         Type[] types = {Hibernate.INTEGER, Hibernate.INTEGER};
56.         criteria.add(Restrictions.sqlRestriction("{alias}.age BETWEEN (?) AND (?)", ages, types));
57.         users = criteria.list();
58.         printUserInfo(users);
59.         
60.         criteria = session.createCriteria(User.class);
61.         criteria.setFirstResult(3); 
62.         criteria.setMaxResults(2);
63.         users = criteria.list();
64.         printUserInfo(users);
65.         
66.         criteria = session.createCriteria(User.class);
67.         criteria.setProjection(Projections.rowCount());
68.         users = criteria.list();
69.         Iterator iterator = users.iterator();
70.         while (iterator.hasNext()) {
71.             System.out.println(iterator.next());
72.         }
73.         
74.         criteria = session.createCriteria(User.class);
75.         criteria.setProjection(Projections.avg("age"));
76.         users = criteria.list();
77.         iterator = users.iterator();
78.         while (iterator.hasNext()) {
79.             System.out.println(iterator.next());
80.         }
81.         
82.         criteria = session.createCriteria(User.class);
83.         criteria.setProjection(Projections.groupProperty("age"));
84.         users = criteria.list();
85.         iterator = users.iterator();
86.         while (iterator.hasNext()) {
87.             System.out.println(iterator.next());
88.         }
89.         
90.         ProjectionList projectionList = Projections.projectionList();
91.         projectionList.add(Projections.groupProperty("age"));
92.         projectionList.add(Projections.groupProperty("name"));
93.         projectionList.add(Projections.rowCount());
94.         criteria = session.createCriteria(User.class);
95.         criteria.setProjection(projectionList);
96.         users = criteria.list();
97.         iterator =  users.iterator();
98.         while(iterator.hasNext()) {
99.             Object[] o = (Object[]) iterator.next();
100.             System.out.println(o[0] + "/t" + o[1] + "/t" + o[2]);
101.         }
102.         
103.         criteria = session.createCriteria(User.class);
104.         criteria.add(Property.forName("name").like("%ya%"));
105.         criteria.addOrder(Property.forName("age").desc());
106.         users = criteria.list();
107.         printUserInfo(users);
108.         
109.         User user = new User();
110.         user.setAge(new Integer(26));
111.         criteria = session.createCriteria(User.class);
112.         criteria.add(Example.create(user));
113.         users = criteria.list();
114.         printUserInfo(users);
116.         
117.         session.close();
118.         sessionFactory.close();
119.     }
120.     
121.     public static void printUserInfo(List users){
122.         
123.         Iterator iterator = users.iterator();
124.         System.out.println("id /t name/age");
125.         while (iterator.hasNext()) {
126.             User user = (User) iterator.next();
127.             System.out.println(user.getId() + " /t " + user.getName() + "/" + user.getAge());
128.         }
129.     }
130. }

运行结果如下：

15:41:36,312  WARN ConfigurationFactory:127 - No configuration found. Configuring ehcache from ehcache-failsafe.xml  found in the classpath: jar:file:/D:/Java/MyEclipse%206.0/workspace/hb3demo/ehcache-1.2.3.jar!/ehcache-failsafe.xml
15:41:36,750  WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.UpdateTimestampsCache]; using defaults.
15:41:36,781  WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.StandardQueryCache]; using defaults.
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ order by this_.age asc
id   name/age
11   yangye/null
12   yangye/null
9   yangye/23
10   yangye/23
2   chenyan/26
1   shenbin/28
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ where this_.age>? and this_.ageid   name/age
2   chenyan/26
9   yangye/23
10   yangye/23
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ where (this_.age=? or this_.age is null)
id   name/age
9   yangye/23
10   yangye/23
11   yangye/null
12   yangye/null
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ where this_.name LIKE (?)
id   name/age
2   chenyan/26
9   yangye/23
10   yangye/23
11   yangye/null
12   yangye/null
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ where this_.age BETWEEN (?) AND (?)
id   name/age
1   shenbin/28
2   chenyan/26
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ limit ?, ?
id   name/age
10   yangye/23
11   yangye/null
Hibernate: select count(*) as y0_ from user this_
6
Hibernate: select avg(this_.age) as y0_ from user this_
25.0
Hibernate: select this_.age as y0_ from user this_ group by this_.age
null
23
26
28
Hibernate: select this_.age as y0_, this_.name as y1_, count(*) as y2_ from user this_ group by this_.age, this_.name
null yangye 2
23 yangye 2
26 chenyan 1
28 shenbin 1
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ where this_.name like ? order by this_.age desc
id   name/age
2   chenyan/26
9   yangye/23
10   yangye/23
11   yangye/null
12   yangye/null
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ where (this_.age=?)
id   name/age
2   chenyan/26

 

注意：

Restrictions的几个常用限定查询方法如下表所示：

方法	说明
Restrictions.eq	等于
Restrictions.allEq	使用Map，使用key/value进行多个等于的比对
Restrictions.gt	大于 >
Restrictions.ge	大于等于 >=
Restrictions.lt	小于 <
Restrictions.le	小于等于 <=
Restrictions.between	对应SQL的BETWEEN子句
Restrictions.like	对应SQL的LIKE子句
Restrictions.in	对应SQL的in子句
Restrictions.and	and关系
Restrictions.or	or关系
Restrictions.sqlRestriction	SQL限定查询

 

此外，Criteria还可以进行复合查询。即在原有的查询基础上再进行查询，例如在Room对User的一对多关系中，在查询出所有的Room資料之后，希望再查询users中"age"为30的user資料：

1. Criteria roomCriteria = session.createCriteria(Room.class);
2. Criteria userCriteria = roomCriteria.createCriteria("users");
3. userCriteria.add(Restrictions.eq("age", new Integer(30)));
4. List rooms = roomCriteria.list(); // 只列出users属性中有user之"age"为30的Room
5. Iterator iterator = rooms.iterator();

这个涉及到对象的关联映射，在后续章节中还会着重讲述。