實現(xiàn)方式

1.通過mybatis編寫xml

    <resultMap id="BaseResultMap" type="com.gy.hd.common.vo.MenuRoleVO">
        <id property="menuId" column="menu_id"/>
        <result column="menu_name" property="menuName"/>
        <result column="menu_url" property="menuUrl"/>
        <result column="parent_id" property="parentId"/>
        <result column="menu_type" property="menuType"/>
        <result column="menu_icon" property="menuIcon"/>
        <!--單個參數(shù)column="menu_id",多個參數(shù)column="{menuId=menu_id蛤奥，cc=cc}"-->
        <collection property="menuList" ofType="com.gy.hd.common.vo.MenuRoleVO" select="com.gy.hd.user.dao.RoleMenuDao.findCaseMenuByRole" column="{menuId=menu_id}">
        </collection>
    </resultMap>


    <!--查詢樹級菜單-->
    <select id="findCaseMenuByRole" resultMap="BaseResultMap" >
        select distinct a.menu_id ,a.parent_id,a.menu_url,a.menu_name ,a.menu_type,a.menu_icon
        from hdhr_menu a inner join hdhr_role_menu b on a.menu_id = b.menu_id
        where a.is_enable = 1
        <choose>
            <when test="menuId != null ">
                and a.parent_id = #{menuId}
            </when>
            <otherwise>
                and a.parent_id is null
            </otherwise>
        </choose>
        order By a.sort asc
</select>

2.通過遞歸算法獲取

public class TreeStructure {
    /**
     * 循環(huán)父級菜單 ---調(diào)用父級菜單即可
     * @param menuList
     * @return
     */
    public static List<MenuRoleVO> loopFatherMenuWithRole(List<MenuRoleVO> menuList){
        List<MenuRoleVO> treeList = new ArrayList<>();
        for(MenuRoleVO menuVO:menuList){
            if(StringUtils.isBlank(menuVO.getParentId())){
                treeList.add(loopChildrenMenuWithRole(menuList,menuVO));
            }
        }
        return treeList;
    }
    /**
     * 循環(huán)子集菜單
     * @param menuList
     * @param fatherMenuVO
     */
    public static MenuRoleVO loopChildrenMenuWithRole(List<MenuRoleVO> menuList,MenuRoleVO fatherMenuVO){
        String fatherId =  fatherMenuVO.getMenuId();
        for(MenuRoleVO childrenMenu:menuList){
            String childrenFatherId = childrenMenu.getParentId();
            if(StringUtils.equals(fatherId,childrenFatherId)){
                fatherMenuVO.getMenuList().add(loopChildrenMenuWithRole(menuList,childrenMenu));
            }
        }
        return  fatherMenuVO;
    }

}