hibernate联合主键(composite-id)

Hibernate联合主键(composite-id)

2010-11-02 22:16 4306人阅读 评论(0) 收藏 举报hibernateclassstringsessiondatabasejdbc
Student.javapackage com.model;
public class Student {private PKStudent pk;private String sex;public PKStudent getPk() { return pk;
}public void setPk(PKStudent pk) { this.pk = pk;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}

}
PKStudent.javapackage com.model;

import java.io.Serializable;

public class PKStudent implements Serializable{
private int 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;
}
private String name;
}
StudentTest.javapackage com.model;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
//import org.hibernate.cfg.Configuration;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class StudentTest {
private static SessionFactory sf=null;
@BeforeClass
public static void beforeClass()
{
try {
sf=(new Configuration()).configure().buildSessionFactory();
} catch (HibernateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Test
public void testStudentSave()
{ PKStudent pk=new PKStudent();
pk.setId(1);
pk.setName("南山");
Student s=new Student();
s.setPk(pk);
s.setSex("女");

Session session=sf.openSession();
session.beginTransaction();
session.save(s);
session.getTransaction().commit();
session.close();
// sf.close();
}
@AfterClass
public static void afterClass()
{
sf.close();
}

}
Student.hbm.xml<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.model">
<class name="Student" table="_student">
<composite-id name="pk">
<key-property name="id"/>
<key-property name="name"/>
</composite-id>

<property name="sex"/>
</class>

</hibernate-mapping>注意：<composite-id>中name=”pk”一定要写，否则会报错；也不能写成其他的值，因为在Student.java中设置联合主键为pk。<class>中的name也不能写成student。参考文档：<class>中name (optional): the fully qualified Java class name of the persistent class or interface. If this attribute is missing, it is assumed that the mapping is for a non-POJO entity.由此可见，name是作为类名的。
hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/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/hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">huangjing</property>

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

<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</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.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/model/Student.hbm.xml"/>

</session-factory>

</hibernate-configuration>
注意：联合主键中作为主键类，一定要实现serializable类。