Hibernate入门

Hibernate入门可参考：

http://www.cnblogs.com/eflylab/archive/2007/01/09/615338.html

关于ThreadLocal

http://www.iteye.com/topic/103804

 

一个Demo:

1、PO=POJO+持久化注解(或者对象映射文件)

@Entity
@Table(name="news_inf")
public class News {
    //标识属性
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;
    //消息标题
    private String title;
    //消息内容
    private String content;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }    
 
}

2、hibernate配置文件（hibernate.cfg.xml）

<?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>
        <!-- configuration properties for JDBC -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost/hibernate</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">root</property>
 
        <!-- configuration properties for the c3p0 connection pool -->
        <property name="hibernate.c3p0.min_size">1</property>
        <property name="hibernate.c3p0.max_size">20</property>
        <property name="hibernate.c3p0.timeout">5000</property>
        <property name="hibernate.c3p0.max_statements">100</property>
        <property name="hibernate.c3p0.idle_test_period">3000</property>
        <property name="hibernate.c3p0.acquire_increment">2</property>
        <property name="hibernate.c3p0.validate">true</property>
 
        <!-- database dialect -->
        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
 
           <!-- Echo all executed SQL to standard out -->
        <property name="show_sql">true</property>
 
        <!-- format SQL before print -->
        <property name="hibernate.format_sql">true</property>
 
        <!-- Drop and re-create the database schema on startup -->
            <property name="hbm2ddl.auto">update</property>
 
            <!-- mapping -->
        <mapping class="com.wj.app.pojo.News"/>
 
    </session-factory>
</hibernate-configuration>

3、JAR包(lib下required子目录 + mysql-connector-java-5.1.30-bin.jar + lib下optionalC3P0子目录)

 

4、操作步骤

•         获取Configuration
•         获取SessionFactory
•         获取Session，打开事务
•         用面向对象的方式操作数据库
•         关闭事务，关闭session

public class NewsManager {
 
    public static void main(String[] args) {
        Configuration conf = new Configuration()
                                 .configure();
        ServiceRegistry serviceRegistry = new ServiceRegistryBuilder()
                                                .applySettings(conf.getProperties())
                                                .buildServiceRegistry();
        SessionFactory sessionFactory = conf.buildSessionFactory(serviceRegistry);
        Session session = sessionFactory.openSession();
 
        Transaction transaction = session.beginTransaction();
 
        News news =new News();        
        news.setTitle("news1");        
        news.setContent("news1Content");
 
        session.save(news);        
        transaction.commit();
 
        session.close();
        sessionFactory.close();        
    }
 
}