hibernate3学习笔记(七)｜Criteria Queries

示例代码如下：

package com.hb3.pack_01;
import java.util.Iterator;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Example;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Property;
import org.hibernate.criterion.Restrictions;
import org.hibernate.type.Type;
import com.hb3.pack_01.model.User;
public class BusinessService {
public static void main(String[] args) {
Configuration config = new Configuration().configure();
SessionFactory sessionFactory = config.buildSessionFactory();
Session session = sessionFactory.openSession();
Criteria criteria = session.createCriteria(User.class);
criteria.addOrder(Order.asc("age"));
List<?> users = criteria.list();
printUserInfo(users);
criteria = session.createCriteria(User.class);
criteria.add(Restrictions.gt("age", new Integer(22)));
criteria.add(Restrictions.lt("age", new Integer(27)));
users = criteria.list();
printUserInfo(users);
criteria = session.createCriteria(User.class);
criteria.add(Restrictions.or(
Restrictions.eq("age", new Integer(23)),
Restrictions.isNull("age")
));
users = criteria.list();
printUserInfo(users);
criteria = session.createCriteria(User.class);
criteria.add(Restrictions.sqlRestriction("{alias}.name LIKE (?)", "%ya%", Hibernate.STRING));
users = criteria.list();
printUserInfo(users);
criteria = session.createCriteria(User.class);
Integer[] ages = {new Integer(26), new Integer(28)};
Type[] types = {Hibernate.INTEGER, Hibernate.INTEGER};
criteria.add(Restrictions.sqlRestriction("{alias}.age BETWEEN (?) AND (?)", ages, types));
users = criteria.list();
printUserInfo(users);
criteria = session.createCriteria(User.class);
criteria.setFirstResult(3);
criteria.setMaxResults(2);
users = criteria.list();
printUserInfo(users);
criteria = session.createCriteria(User.class);
criteria.setProjection(Projections.rowCount());
users = criteria.list();
Iterator<?> iterator = users.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
criteria = session.createCriteria(User.class);
criteria.setProjection(Projections.avg("age"));
users = criteria.list();
iterator = users.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
criteria = session.createCriteria(User.class);
criteria.setProjection(Projections.groupProperty("age"));
users = criteria.list();
iterator = users.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
ProjectionList projectionList = Projections.projectionList();
projectionList.add(Projections.groupProperty("age"));
projectionList.add(Projections.groupProperty("name"));
projectionList.add(Projections.rowCount());
criteria = session.createCriteria(User.class);
criteria.setProjection(projectionList);
users = criteria.list();
iterator = users.iterator();
while(iterator.hasNext()) {
Object[] o = (Object[]) iterator.next();
System.out.println(o[0] + ""t" + o[1] + ""t" + o[2]);
}
criteria = session.createCriteria(User.class);
criteria.add(Property.forName("name").like("%ya%"));
criteria.addOrder(Property.forName("age").desc());
users = criteria.list();
printUserInfo(users);
User user = new User();
user.setAge(new Integer(26));
criteria = session.createCriteria(User.class);
criteria.add(Example.create(user));
users = criteria.list();
printUserInfo(users);
session.close();
sessionFactory.close();
}
public static void printUserInfo(List<?> users){
Iterator<?> iterator = users.iterator();
System.out.println("id "t name/age");
while (iterator.hasNext()) {
User user = (User) iterator.next();
System.out.println(user.getId() + " "t " + user.getName() + "/" + user.getAge());
}
}
}

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_.age<?
id 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：

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

ExtJS教程- Hibernate教程-Struts2 教程-Lucene教程

发表于 2008-10-29 19:31 淘声依旧阅读(327) 评论(0) 编辑收藏所属分类: 103.Hibernate

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