Mybatis之高級映射collection （遞歸查出樹形數據 ）

第一步：創建樹形數據Bean

public class DeptTree {
private String id;
private String name;
private List<DeptTree> childrenList;//子節點
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<DeptTree> getChildrenList() {
return childrenList;
}
public void setChildrenList(List<DeptTree> childrenList) {
this.childrenList = childrenList;
}
}

第二步：mybatis相應的sql.xml文件配置

<!-- 初始化部門樹 -->
<resultMap type="com.lilosoft.cospace.sys.bean.DeptTree" id="deptTree">
<result column="DEPT_ID" property="id" javaType="java.lang.String" />
<result column="DEPT_NAME" property="name" javaType="java.lang.String" />
<collection column="DEPT_ID" property="childrenList" ofType="DeptTree" javaType="java.util.ArrayList" select="selectDeptChildrenById"/>
</resultMap>
<!-- 根據parent_id，先查出所有一級部門 -->
<select id="queryDeptTreeList" resultMap="deptTree">
select dept_id,dept_name from sys_dept  where is_use='0' and parent_id= (select dept_id from sys_dept where parent_id='-1' and is_use='0')
</select>
<!-- 再遞歸查詢出一級部門下的所有子部門 -->
<select id="selectDeptChildrenById" resultMap="deptTree" parameterType="string">
select dept_id,dept_name from sys_dept  where is_use='0' and parent_id= #{DEPT_ID}
</select>

第三步：（dao和service層代碼略）控制器調用

List<DeptTree> dList=deptService.queryDeptTreeList();