hibernate组件映射

对象关系: 一个对象是另外一个对象的一部分

数据库表: 一张表

比如一个学生有一个学生证, 学生证有很多信息.

一个wife属于一个husband:

1. wife.java: id去掉, 不需要主键, 因为是husband的一部分

package com.bjsxt.hibernate;
public class Wife {
private String wifeName;
private int age;
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getWifeName() {
return wifeName;
}
public void setWifeName(String name) {
this.wifeName = name;
}
}

2. husband.java: 加入@Embedded

package com.bjsxt.hibernate;

import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinColumns;
import javax.persistence.OneToOne;

@Entity
public class Husband {
private int id;
private String name;
private Wife wife;
@Id
@GeneratedValue
public int getId() {
return id;
}

public String getName() {
return name;
}
@Embedded
public Wife getWife() {
return wife;
}
public void setId(int id) {
this.id = id;
}
public void setName(String name) {
this.name = name;
}
public void setWife(Wife wife) {
this.wife = wife;
}

}

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>

<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">linda0213</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!--
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:SXT</property>
<property name="connection.username">scott</property>
<property name="connection.password">tiger</property>
<property name="dialect">org.hibernate.dialect.OracleDialect</property>
-->

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

<!-- Drop and re-create the database schema on startup
<property name="hbm2ddl.auto">update</property>
-->
<mapping class="com.bjsxt.hibernate.Husband"/>
<!-- <mapping resource="com/bjsxt/hibernate/Husband.hbm.xml"/> -->

</session-factory>

</hibernate-configuration>

test文件:

package com.bjsxt.hibernate;

import java.util.Date;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateORMappingTest {
private static SessionFactory sessionFactory;

//@BeforeClass
public static void beforeClass() {
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
//@AfterClass
public static void afterClass() {
sessionFactory.close();
}

@Test
public void testSchemaExport() {
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
}

public static void main(String[] args) {
beforeClass();
}
}

　　

XML方式:

加入Husband.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>
<class name="com.bjsxt.hibernate.Husband" >
<id name="id">
<generator class="native"></generator>
</id>

<property name="name"></property>
<component name="wife">
<property name="wifeName"></property>
<property name="age"></property>
</component>
</class>

</hibernate-mapping>

hibernate.cfg.xml配置:

<mapping resource="com/bjsxt/hibernate/Husband.hbm.xml"/>