hibernate组件映射

类组合关系的映射，也叫做组件映射！

注意：组件类和被包含的组件类，共同映射到一张表！

需求： 汽车与车轮

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

<!-- 
    组件映射
 -->
<hibernate-mapping package="loaderman.d_component">
    
    <class name="Car" table="t_car">
        <id name="id">
            <generator class="native"></generator>
        </id>    
        <property name="name" length="20"></property>
        
        <!-- 组件映射 -->
        <component name="wheel">
            <property name="size"></property>
            <property name="count"></property>
        </component>
        
                     
    </class>
    

</hibernate-mapping>

package loaderman.d_component;

import org.hibernate.Hibernate;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.classic.Session;
import org.junit.Test;

public class App {

    private static SessionFactory sf;
    static {
        sf = new Configuration()
                .configure()
                .addClass(Car.class)
                .buildSessionFactory();
    }

    @Test
    public void getSave() {

        Session session = sf.openSession();
        session.beginTransaction();

        // 轮子
        Wheel wheel = new Wheel();
        wheel.setSize(38);
        wheel.setCount(4);
        // 汽车
        Car car = new Car();
        car.setName("BMW");
        car.setWheel(wheel);

        // 保存
        session.save(car);

        session.getTransaction().commit();
        session.close();

    }

}

package loaderman.d_component;

public class Car {

    private int id;
    private String name;
    // 车轮
    private Wheel wheel;
    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 Wheel getWheel() {
        return wheel;
    }
    public void setWheel(Wheel wheel) {
        this.wheel = wheel;
    }
    
}

package loaderman.d_component;
// 车轮
public class Wheel {

    private int count;
    private int size;
    public int getCount() {
        return count;
    }
    public void setCount(int count) {
        this.count = count;
    }
    public int getSize() {
        return size;
    }
    public void setSize(int size) {
        this.size = size;
    }
    
    
}

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