单向List/Array映射:

Bean:

public class Car implements Serializable{

    private int id ;
    
    private String name ;
    ....
}
public class User implements Serializable {
    
    private int id ;
    
    private String name ;
    
    private List<Car> cars ;
        ....
}

xml:

Car.hbm.xml:
<class name = "Car">
        <!-- id是来配置主键 
             name是类中的哪个属性和主键映射
             generator:表示主键的生成策略
        -->
        <id name = "id">
            <generator class="native" />
        </id>
        <!-- property是用来把类中的属性和表的字段做一一对应 -->
        <property name="name" />
        
    </class>
User.hbm.xml:
<class name = "User">
        <!-- id是来配置主键 
             name是类中的哪个属性和主键映射
             generator:表示主键的生成策略
        -->
        <id name = "id">
            <generator class="native" />
        </id>
        <!-- property是用来把类中的属性和表的字段做一一对应 -->
        <property name="name" />
        
        <list name="cars">
            <key column="uid" />
            <list-index column="carindex" />
            <one-to-many class="Car"/>
        </list>
    </class>

单向Map映射:

Bean:

public class Car implements Serializable{

    private int id ;
    
    private String name ;
    ....
}
public class User implements Serializable {
    
    private int id ;
    
    private String name ;
    
    private Map<String,Car> cars ;
        ....
}

xml:

Car.hbm.xml:
<class name = "Car">
        <!-- id是来配置主键 
             name是类中的哪个属性和主键映射
             generator:表示主键的生成策略
        -->
        <id name = "id">
            <generator class="native" />
        </id>
        <!-- property是用来把类中的属性和表的字段做一一对应 -->
        <property name="name" />
        
    </class>
User.hbm.xml:
<class name = "User">
        <!-- id是来配置主键 
             name是类中的哪个属性和主键映射
             generator:表示主键的生成策略
        -->
        <id name = "id">
            <generator class="native" />
        </id>
        <!-- property是用来把类中的属性和表的字段做一一对应 -->
        <property name="name" />
        
        <map name="cars">
            <key column="uid" />
            <!-- <map-key记录键 -->
            <map-key column="mk" type = "string"/>
            <one-to-many class="Car"/>
        </map>
        
    </class>