Hibernate4入门教程：Hello World！

来源：互联网发布：始祖鸟羽绒服知乎编辑：程序博客网时间：2024/05/22 03:08

一、配置hibernate.cfg.xml文件中的属性自动提示功能

1、配置如下图，将http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd放入第三步的文本框中

二、HelloWorld

2、在 http://sourceforge.net/projects/hibernate/files/hibernate4/下载hibernate-release-4.2.4.Final.zip

3、创建一个普通的java项目，在根目录下创建一个名称为“lib”的文件夹用来存放导入的jar包.

4、选择hibernate必须的jar包导入项目，将下载的hibernate-release-4.2.4.Final.zip解压开，选择hibernate-release-4.2.4.Final\lib\required下面的所有jar包。

5、 Hibernate的jar包导入之后就需要导入mysql的驱动包

6、在src目录下创建hibernate的配置文件hibernate.cfg.xml，步骤如下：

a) 在项目名称上右键【New】->【other】，选择Hibernate Configuration file，然后【Next>】

b) 默认名字就叫【hibernate.cfg.xml】，然后直接【Finish】就可以了

Hibernate.cfg.xml配置文件的内容如下

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEhibernate-configuration PUBLIC

"-//Hibernate/Hibernate Configuration DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<propertyname="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property>

<propertyname="hibernate.connection.username">root</property>

<propertyname="hibernate.connection.password">allyroot</property>

<propertyname="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>

<propertyname="dialect">org.hibernate.dialect.MySQLInnoDBDialect</property>

<propertyname="show_sql">true</property>

<propertyname="format_sql">true</property>

<!-- create:会根据.hbm.xml文件生成新的数据表，每次都会删除上一次的表，重新生成表 create-drop:会根据.hbm.xml文件生成新的数据表，但SessionFactory一关闭，表就自动删除

update:最常用的属性，会根据.hbm.xml文件生成新的数据表，若.hbm.xml文件和数据表中对应的数据表结构不不同，Hibernate会更新数据表结构，但不会删除已经有的列和行

validate:会和数据表进行比较，若.hbm.xml文件中的列在数据表中不存在，则抛出异常 -->

<propertyname="hbm2ddl.auto">update</property>

<mappingresource="pojo/News.hbm.xml"/>

</session-factory>

</hibernate-configuration>

7、在src下创建pojo包，并创建News.java类，代码如下

package pojo;

import java.util.Date;

public class News {

private Integerid;

private Stringtitle;

private Stringcontent;

private Datetime;

public Integer getId() {

returnid;

}

public void setId(Integer id) {

this.id = id;

}

public String getTitle() {

returntitle;

}

public void setTitle(String title) {

this.title = title;

}

public String getContent() {

returncontent;

}

public void setContent(String content) {

this.content = content;

}

public Date getTime() {

returntime;

}

public void setTime(Date time) {

this.time = time;

}

public News() {

}

public News(String title, String content, Date time) {

super();

this.title = title;

this.content = content;

this.time = time;

}

@Override

public String toString() {

return"News [id=" + id +", title=" + title +", content=" + content +", time=" + time +"]";

}

8、根据pojo生成对应的hbm.xml配置文件步骤如下：

a) 在pojo包上右键【New】->【other】，选择Hibernate XML Mapping file，然后【Next>】

b) 选择要生成实体类的包，直接【Finish】就可以生成对应的hbm.xml文件

c) 生成对应的hbm.xml文件信息如下：

<?xmlversion="1.0"?>

<!DOCTYPEhibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<classname="pojo.News"table="NEWS"lazy="false">

<idname="id"type="java.lang.Integer">

<columnname="ID"/>

<generatorclass="native"/>

</id>

<propertyname="title"type="java.lang.String">

<columnname="TITLE"/>

</property>

<propertyname="content"type="java.lang.String">

<columnname="CONTENT"/>

</property>

<propertyname="time"type="java.util.Date">

<columnname="TIME"/>

</property>

</class>

</hibernate-mapping>

9、在src下创建test包，用来写测试方法，代码如下

a) 新增：

package test;

import java.util.Date;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

import org.hibernate.service.ServiceRegistryBuilder;

import org.junit.Test;

import pojo.News;

public class Insert {

@Test

public void testName() throws Exception {

SessionFactory sessionFactory = null;

Configuration configuration = new Configuration().configure();

// Hibernate 的任何配置都需要在serviceRegistry中注册之后才有效

ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())

.buildServiceRegistry();

sessionFactory = configuration.buildSessionFactory(serviceRegistry);

// 4.0之前的创建方式

// sessionFactory = configuration.buildSessionFactory();

Session session = sessionFactory.openSession();

// 开启事务

Transaction transaction = session.beginTransaction();

News news = new News("新闻","内容",new Date());

try {

session.save(news);

transaction.commit();

} catch (Exception e) {

e.printStackTrace();

transaction.rollback();

}

session.close();

sessionFactory.close();

}

注意：

1、由于Hibernate.cfg.xml中hbm2ddl.auto这个配置的是“update”，所以不需要创建数据库表，程序会在运行的时候自动根据*.hbm.xml文件自动创建数据库表，至于如何从数据库表中生成对应的*.hbm.xml配置文件会在以后的博客中写出。

2、Test类中的test()方法在运行的时候需要选择JUnitTest方式，同时还需要将JUnit的包引入项目中，这里就不在描述如何引入JUnit包的方法了。

b) 查询：

package test;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

import org.hibernate.service.ServiceRegistryBuilder;

import org.junit.After;

import org.junit.Before;

import org.junit.Test;

import pojo.News;

public class Query {

private SessionFactory sessionFactory;

private Sessionsession;

private Transactiontransaction;

@Before

public void init() {

Configuration configuration = new Configuration().configure();

ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())

.buildServiceRegistry();

sessionFactory = configuration.buildSessionFactory(serviceRegistry);

session = sessionFactory.openSession();

transaction = session.beginTransaction();

}

@After

public void destory() {

transaction.commit();

session.close();

sessionFactory.close();

}

@Test

public void test() {

News news = (News) session.get(News.class, 1);

System.out.println(news.getContent());

}

c) 修改：

package test;

import java.util.Date;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

import org.hibernate.service.ServiceRegistryBuilder;

import org.junit.Test;

import pojo.News;

public class Update {

private SessionFactorysessionFactory;

private Sessionsession;

private Transactiontransaction;

@Test

public void test() throws Exception {

Configuration configuration = new Configuration().configure();

ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())

.buildServiceRegistry();

sessionFactory = configuration.buildSessionFactory(serviceRegistry);

session = sessionFactory.openSession();

transaction = session.beginTransaction();

News news = (News) session.get(News.class, 3);

news.setContent("内容1");

news.setTime(new Date());

// session.update(news);

session.update(news);

transaction.commit();

session.clear();

sessionFactory.close();

}

d) 删除：

package test;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

import org.hibernate.service.ServiceRegistryBuilder;

import org.junit.Test;

import pojo.News;

public class Delete {

private SessionFactorysessionFactory;

private Sessionsession;

private Transactiontransaction;

@Test

public void test() throws Exception {

Configuration configuration = new Configuration().configure();

ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())

.buildServiceRegistry();

sessionFactory = configuration.buildSessionFactory(serviceRegistry);

session = sessionFactory.openSession();

transaction = session.beginTransaction();

session.delete(session.get(News.class, 1));

transaction.commit();

session.close();

sessionFactory.close();

}

0 0