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