学步园

Hibernate 4.0与之前的3.X版本改进很很多，下面先将改动的地方说一下。

1.数据库方言设置

<property name=”dialect”>org.hibernate.dialect.MySQL5Dialect</property>

在3.3版本中连接MySQL数据库只需要指明MySQLDialect即可。在4.1版本中可以指出MySQL5Dialect

2.buildSessionFactory

4.1版本中buildSessionFactory()已经被buildSessionFactory(ServiceRegistry ServiceRegistry)取代

解决办法：

Configuration cfg = new Configuration();

cfg.configure();
ServiceRegistry serviceRegistry =new ServiceRegistryBuilder().applySettings(cfg.getProperties()).buildServiceRegistry();

SessionFactory sf = cfg.configure().buildSessionFactory(serviceRegistry);

3.annotation

org.hibernate.cfg.AnnotationConfiguration;

Deprecated. All functionality has been moved to Configuration

这个注解读取配置的class已经废弃，现在读取配置不需要特别注明是注解，直接用Configuration cfg = new Configuration();就可以读取注解。

Hibernate4.1版本中推荐使用annotation配置，所以在引进jar包时把requested里面的包全部引进来就已经包含了annotation必须包了

由于Hibernate推荐使用注解，所以基于hbm的配置文件我们就不写了，而且对于新的server读取配置文件的方法建立session对于配置文件的读取貌似也有问题，我测试了好几个都没办法解决，所以这里先只介绍一下基于注解的方法了。

首先是配置文件，这个在hibernate的mannual里面可以找到

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

        <!-- Database connection settings -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/test</property>
        <property name="connection.username">sa</property>
        <property name="connection.password">sa</property>

        <!-- JDBC connection pool (use the built-in)
        <property name="connection.pool_size">1</property>
		 -->
        <!-- SQL dialect -->
        <property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>

        <!-- Enable Hibernate's automatic session context management 
        <property name="current_session_context_class">thread</property>
		-->
		
        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup
        <property name="hbm2ddl.auto">update</property>
		 -->
		 
     <!--   <mapping resource="com/bird/model/Student.hbm.xml"/> --> 
		<mapping class="com.bird.model.Teacher"/>
    </session-factory>

</hibernate-configuration>

然后是具体的类

package com.bird.model;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Teacher {

	private int id;
	private String name;
	private String title;

	@Id
	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 String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}

}

其中的表名和类名相同，其他的字段和Bean的属相相同。

最后是使用他

package com.bird.test;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

import com.bird.model.Teacher;


public class TeacherTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Teacher t = new Teacher();
		t.setId(1);
		t.setName("t1");
		t.setTitle("中级");
		
		Configuration cfg = new Configuration();
		cfg.configure();//读取配置文件
		
		ServiceRegistry serviceRegistry =new ServiceRegistryBuilder().
		applySettings(cfg.getProperties()).buildServiceRegistry();
		
		SessionFactory factory = cfg.configure().buildSessionFactory(serviceRegistry);
		
		Session session = factory.openSession();
		session.beginTransaction();
		session.save(t);
		session.getTransaction().commit();
		session.close();
		factory.close();
	}

}

这样基于最新的hibernate4.1.1的helloworld就OK了