J2EE之路（六）hibernate（02）HQL和criteria

引言，hibernate的get方法，只能利用主键查询，所以需要HQL完成复杂查询

 

SQL查的是表，而HSQL查询的事对象

 

Query q = session.createQuery(HQL);

from Person

from User user where user.name = :name

from User user where user.name = :name and user.birday < :birday

例子：

static void query01(String name){
		Session s = null;
		try{
			s = HibernateUtil.getSession();
			String hql01 = "from User as user where user.name=?";
			Query query = s.createQuery(hql01);
			query.setString(0,name);
			List<User> userList = query.list();
			
			for(User userItem:userList){
				System.out.println(userItem.getName());
			}
		}finally{
			if(s!=null)
				s.close();
		}
	}

 

与jdbc的却别是HQL没有select，而且当setString时是从零开始的，取值的方法也有些诡异是query.list();

 

Criteria

Criteria是一种更面相对象的查询方式，criteria的查询方式

 

static void cri(String name){
		Session s = null;
		try{
			s = HibernateUtil.getSession();
			Criteria c = s.createCriteria(User.class);
			c.add(Restrictions.eq("name", name));//加入一个约束条件
			List<User> userList = c.list();
			
			for(User userItem:userList){
				System.out.println(userItem.getName());
			}
		}finally{
			if(s!=null)
				s.close();
		}
	}

 

 怀着激动的心情，使用阔别4年的hibernte完成CRUD。

 

 

package dao;

import domain.User;

public interface UserDao {
	public void saveUser(User user);
	public void removeUser(User user);
	public void updateUser(User user);
	public User getUserById(int id);
	public User getUserByName(String name);
}

  

 

package dao.impl;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.criterion.Restrictions;

import Util.HibernateUtils;

import dao.UserDao;
import domain.User;

public class UserDaoHibernateImpl implements UserDao {

	@Override
	public void saveUser(User user) {
		Session session = null;
		Transaction transaction = null;
		try{
			session = HibernateUtils.getSession();
			transaction = session.beginTransaction();
			session.save(user);
			transaction.commit();
		}catch(Exception e){
			e.printStackTrace();
			transaction.rollback();
		}finally{
			session.close();
		}
	}

	@Override
	public void removeUser(User user) {
		Session session = null;
		Transaction transaction = null;
		try{
			session = HibernateUtils.getSession();
			transaction = session.beginTransaction();
			session.delete(user);
			transaction.commit();
		}catch(Exception e){
			e.printStackTrace();
			transaction.rollback();
		}finally{
			session.close();
		}
	}

	@Override
	public void updateUser(User user) {
		Session session = null;
		Transaction transaction = null;
		try{
			session = HibernateUtils.getSession();
			transaction = session.beginTransaction();
			session.update(user);
			transaction.commit();
		}catch(Exception e){
			e.printStackTrace();
			transaction.rollback();
		}finally{
			session.close();
		}
	}

	@Override
	public User getUserById(int id) {
		Session session = null;
		try{
			session = HibernateUtils.getSession();
			User user = (User)session.get(User.class, id);
			return user;
		}finally{
			session.close();
		}
	}

	@Override
	public User getUserByName(String name) {
		Session session = null;
		try{
			session = HibernateUtils.getSession();
			Criteria criteria = session.createCriteria(User.class);
			criteria.add(Restrictions.eq("name","test05"));
			User user = (User)criteria.uniqueResult();
			return user;
		}finally{
			session.close();
		}
	}

}

 

package domain;

import java.util.Date;

public class User {
	private int id;
	private String name;
	private Date birthday;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
}

 

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
	"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="domain">
	<class name="User">
		<id name="id">
			<generator class="native"/>
		</id>
		<property name="name" unique="true"/>
		<property name="birthday"/>
	</class>
</hibernate-mapping>

 

package Util;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public final class HibernateUtils {
	private static SessionFactory sessionFactory;
	private HibernateUtils(){
	}
	static{
		Configuration cfg = new Configuration();
		cfg.configure();
		SessionFactory sf = cfg.buildSessionFactory();
	}
	public static SessionFactory getSessionFactory(){
		return sessionFactory;
	}
	public static Session getSession(){
		return sessionFactory.openSession();
	}
}

 

<!DOCTYPE hibernate-configuration PUBLIC
	"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
	<session-factory>
		<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="hibernate.connection.url">jdbc:mysql:///test</property>
		<property name="hibernate.connection.username">root</property>
		<property name="hibernate.connection.password"></property>
		<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
		<property name="hibernate.hbm2ddl.auto">validate</property>
		<property name="show_sql">true</property>
		<mapping resource="domain/User.hbm.xml"/>
	</session-factory>
</hibernate-configuration>