将一个对象（组件）作为属性，但是不想建立这个表

如果对象的某个属性为一个对象，而且不想单独对该对象建立一个表，这时Hibernate是这样处理的：

public class Name {


	private String firstName;
	private String SecondName;
	public String getFirstName() {
		return firstName;
	}
	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}
	public String getSecondName() {
		return SecondName;
	}
	public void setSecondName(String secondName) {
		SecondName = secondName;
	}


}

public class Employee {

	private Integer id;
	private Name name;
	private Integer age;

	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public Name getName() {
		return name;
	}
	public void setName(Name name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
}

注意映射文件：

<?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="cn.itcast.hibernate.domain">

	<class name="Employee" table="employee">
		<id name="id" unsaved-value="-1">
			<generator class="native" />
		</id>
		<property name="age" />
		<component name="name">
			<property name="firstName" column="first_name"/>
			<property name="SecondName" column="second_name"/>
		</component>
	</class>
</hibernate-mapping>

测试代码：

import org.hibernate.Session;
import org.hibernate.Transaction;

import cn.itcast.hibernate.HibernateUtil;
import cn.itcast.hibernate.domain.Employee;
import cn.itcast.hibernate.domain.Name;

public class ComponentTest {

	public static void main(String[] args) {
		Session session = HibernateUtil.getSession();
		Transaction tx = session.beginTransaction();

		Name name = new Name();
		name.setFirstName("firstname");
		name.setSecondName("secondname");

		Employee employee = new Employee();
		employee.setAge(30);
		employee.setName(name);

		session.save(employee);

		tx.commit();
		session.close();
	}

}

关键是映射文件中采用的标签component.

最终在数据库中生成的表的结构：

id int
age int
firstname varchar
secondname varchar

即所有字段都出现在同一个表中