hibernate4.2.1_HelloWorld学习例子

这次学习hibernate用的版本是 hibernate-release-4.2.1.Final。由于刚开始学，新旧版本间的差异比自己想像中的多，导致弄了整整两天才实现第一个CLASS例子，过程滋味不言而喻。曾经也从网上找过好多例子，但多是问题帖子，完整的例子少得可怜，对新版本的例子更是难以找出，现在把我这两天学到的第一个例子完整贴出来分享给大家，希望对新学的有点帮助。

工程目录完整结构截图：



只要把hibernate-release-4.2.1.Final下载解压，然后复制lib\required目录下全部JAR包就可以用了，不需要额外下载别的JAR包了，当然了，为了连接数据库MYSQL，还需要一个数据库驱动JAR包。

1、建立一个普通的JAVA工程，名字随便取一个，下面我会建立两个实体类和对应的两张表，分别演示用传统映射配置文件和用注解实现映射的实现过程。

2、建立一个学生和老师类，并分别建立对应的两张表，建表这里就不说了，自己可以完成，需要注意的是建主键。

Student类

package com.luhy.hibernate.model;

public class Student {
private int id;
private String name;
private int age;

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 int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}

}

Ttudent类

package com.luhy.hibernate.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;
}

}

3、建立两个类的对应的测试类;

StudentTest.java

package com.luhy.hibernate.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.luhy.hibernate.model.Student;

public class StudentTest {
public static void main(String[] args) {
Student st = new Student();
st.setId(6);
st.setName("好");
st.setAge(20);

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

ServiceRegistry serviceRegistry =new ServiceRegistryBuilder().applySettings(cfg.getProperties()).buildServiceRegistry();
SessionFactory sf = cfg.buildSessionFactory(serviceRegistry);
Session session = sf.openSession();
session.beginTransaction();               //事务开启
session.save(st);                             //保存对象
session.getTransaction().commit();
session.close();
sf.close();
}
}

TeacherTest.java

package com.luhy.hibernate.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.luhy.hibernate.model.Teacher;

public class TeacherTest {
public static void main(String[] args) {
Teacher t = new Teacher();
t.setId(2);
t.setName("kk");
t.setTitle("oolk");

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

ServiceRegistry serviceRegistry =new ServiceRegistryBuilder().applySettings(cfg.getProperties()).buildServiceRegistry();
SessionFactory sf = cfg.buildSessionFactory(serviceRegistry);
Session session = sf.openSession();
session.beginTransaction();               //事务开启
session.save(t);                             //保存对象
session.getTransaction().commit();
session.close();
sf.close();
}
}

4、hibernate.cfg.xml和Student.hbm.xml

Student.hbm.xml一般放在对应的实体类所在目录下，hibernate.cfg.xml一般放在工程根目录下

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>

<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">lu5896848</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/luhy/hibernate/model/Student.hbm.xml" />
<mapping class="com.luhy.hibernate.model.Teacher"/>

</session-factory>

</hibernate-configuration>

Student.hbm.xml

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

<hibernate-mapping package="com.luhy.hibernate.model">
<class name="Student" table="student">
<id name="id" column="id" />
<property name="name" column="name" />
<property name="age" column="age" />
</class>
</hibernate-mapping>

好了，直接运行上面的应该是没有问题的了，我用的是myeclipse10.5的开发平台。建议大家先了解一些基本的知识再来看上面这些代码，每行代码或配置的具体意思我在这就不解释了，需要大家去查找一下网上别的教程，这里提供的是我自己测试成功的例子。另外，大家在弄配置文件的时候一定要多小心，本人就因某些配置格式，浪费了一天多时间。