12 映射-- 集合类的映射(Set,List,Map,Array)

部门类Department , 他有 empa1, empa2, empa3, empa4是四种集合类型

public class Department {
	private int id;
	private String name;

	private Set<Employee> emps1; //Set

	private List<Employee> emps2; //List

	private Map<String, Employee> emps3; //Map

	private Employee[] emps4; //数组
}

员工类Employee 略...(前面的笔记有这个类)

Set 类型的映射 :

		<set name="emps" inverse="true">
			<key column="depart_id"/>
			<one-to-many class="Employee" />
		</set>

List集合的映射:(要保存顺序 )

		<list name="emps">
			<key column="depart_id" />
			<!-- List集合是有顺序的, 要保存住顺序 -->
			<!-- order_col字段 用来保存顺序-->
			<list-index column="order_col" />
			<one-to-many class="Employee" />
		</list>

List集合的映射:(不要保存顺序 )

		<bag name="emps">
			<key column="depart_id" />
			<one-to-many class="Employee" />
		</bag>

Map 集合的映射:

		<map name="emps">
			<key column="depart_id" />
			<map-key type="string" column="name"/>
			<one-to-many class="Employee" />
		</map>

数组 的映射: (与List一样)

		<array name="emps">
			<key column="depart_id" />
			<!-- 集合是有顺序的, 要保存住顺序 -->
			<!-- order_col字段 用来保存顺序-->
			<list-index column="order_col" />
			<one-to-many class="Employee" />
		</array >