mybaits十二:使用collection嵌套结果集查询

 定义bean, 该bean中有一个集合属性emps

package com.atChina.bean;

import java.util.List;

public class Department {
	private Integer id;
	private List<Employee> emps;


	public List<Employee> getEmps() {
		return emps;
	}


	public void setEmps(List<Employee> emps) {
		this.emps = emps;
	}

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	private Integer deptno;
	private String dname;
	private String loc;
	
	public int getDeptno() {
		return deptno;
	}
	
	public void setDeptno(int deptno) {
		this.deptno = deptno;
	}
	
	public String getDname() {
		return dname;
	}
	
	public void setDname(String dname) {
		this.dname = dname;
	}
	
	public String getLoc() {
		return loc;
	}

	public void setLoc(String loc) {
		this.loc = loc;
	}


	@Override
	public String toString() {
		return "Department [id=" + id + ", emps=" + emps + ", deptno=" + deptno
				+ ", dname=" + dname + ", loc=" + loc + "]";
	}

}

 sql映射文件,使用collection

<resultMap type="com.atChina.bean.Department" id="defineDept">
  	<id column="deptno" property="deptno"/>
  	<result column="dname" property="dname"/>
  	<result column="loc" property="loc"/>
    <!-- 
  		collection:嵌套结果集的方式,定义关联集合类型的属性的封装规则
  		ofType: 指定集合里面元素的类型
  	 -->
  	<collection property="emps" ofType="com.atChina.bean.Employee">
  		<!-- 定义这个集合元素的封装类型 -->
  		<id column="empno" property="empno" />
  		<result column="ename" property="ename" />
  		<result column="job" property="job" />
  		<result column="mgr" property="mgr" />
  		<result column="hiredate" property="hiredate" />
  		<result column="sal" property="sal" />
  	</collection>
  </resultMap>
  <select id="getDepartByDeptnoCol" resultMap="defineDept">
  	select a.empno, a.ename, a.job, a.mgr, a.hiredate, a.sal,
    b.deptno, b.dname, b.loc 
    from depttest b, emptest a 
    where a.deptno = b.deptno
	  and b.deptno = #{deptno}
  </select>