hibernate[版本四]知识总结

1.hibernate是orm对象关系映射，是对jdbc的封装

2.hibernate版helloworld

　　2.1导入jar

<dependencies>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>4.2.21.Final</version>
        </dependency>

        <!-- Hibernate uses jboss-logging for logging, for the tutorials we will use the sl4fj-simple backend -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.6.1</version>
        </dependency>

        <!-- The tutorials use JUnit test cases to illustrate usage -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>

        <!-- The tutorials use the H2 in-memory database -->
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.2.145</version>
        </dependency>
    </dependencies>

　　2.2创建hbm.cfg.xml文件（配置数据源、配置hbm.xml文件）

<!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">org.h2.Driver</property>
        <property name="connection.url">jdbc:h2:mem:db1;DB_CLOSE_DELAY=-1;MVCC=TRUE</property>
        <property name="connection.username">sa</property>
        <property name="connection.password"/>

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

        <!-- SQL dialect -->
        <property name="dialect">org.hibernate.dialect.H2Dialect</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">create</property>

        <mapping resource="org/hibernate/tutorial/hbm/Event.hbm.xml"/>

    </session-factory>

</hibernate-configuration>

　　2.3创建实体类、以及相对应的hbm文件

package org.hibernate.tutorial.hbm;

import java.util.Date;

public class Event {
    private Long id;

    private String title;
    private Date date;

    public Event() {
        // this form used by Hibernate
    }

    public Event(String title, Date date) {
        // for application use, to create new events
        this.title = title;
        this.date = date;
    }

    public Long getId() {
        return id;
    }

    private void setId(Long id) {
        this.id = id;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    public String getTitle() {
        return title;
    }

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

　

<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="org.hibernate.tutorial.hbm">

    <class name="Event" table="EVENTS">
        <id name="id" column="EVENT_ID">
            <generator class="increment"/>
        </id>
        <property name="date" type="timestamp" column="EVENT_DATE"/>
        <property name="title"/>
    </class>

</hibernate-mapping>

　　2.4实例化配置对象

　　2.5注册服务

　　2.6获取sessionFactory，获取session

　　2.7开启事务，调用session的crud操作，关闭事务

　　2.8关闭session

package org.hibernate.tutorial.hbm;

import java.util.Date;
import java.util.List;

import junit.framework.TestCase;

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

/**
 * Illustrates use of Hibernate native APIs.
 *
 * @author Steve Ebersole
 */
public class NativeApiIllustrationTest extends TestCase {
    private SessionFactory sessionFactory;

    @Override
    protected void setUp() throws Exception {
        // A SessionFactory is set up once for an application
        sessionFactory = new Configuration()
                .configure() // configures settings from hibernate.cfg.xml
                .buildSessionFactory();
    }

    @Override
    protected void tearDown() throws Exception {
        if ( sessionFactory != null ) {
            sessionFactory.close();
        }
    }

    public void testBasicUsage() {
        // create a couple of events...
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        session.save( new Event( "Our very first event!", new Date() ) );
        session.save( new Event( "A follow up event", new Date() ) );
        session.getTransaction().commit();
        session.close();

        // now lets pull events from the database and list them
        session = sessionFactory.openSession();
        session.beginTransaction();
        List result = session.createQuery( "from Event" ).list();
        for ( Event event : (List<Event>) result ) {
            System.out.println( "Event (" + event.getDate() + ") : " + event.getTitle() );
        }
        session.getTransaction().commit();
        session.close();
    }
}

3.hibernate删除修改

　　3.1先get或load出来再进行删除

　　3.2先get或load出来再进行修改

4.hibernate利用OID区分对象

　　4.1同一session获取id相同的两个对象，这两个对象指向的引用是相同的

5.主键生成策略（代理主键[无业务意义，如id]、业务主键[有义务意义，如stuNo]）

　　5.1identity

　　5.2native

　　5.3sequence

6.hibernate查询

　　6.1native sql

　　6.2hibernate query language-支持链式操作

　　6.3QBC(hibernate提供的查询接口)-支持链式操作