/**
	 * 根据用户名username和系统systemName去查询菜单信息
	 * @param username 用户名
	 * @param systemName 系统名称
	 * @param parentId 父id(第一次默认传null,表示第一次查的是第一级菜单)
	 * @return
	 */
	@Override
	public List<SysMenu> findMenusByUserName(String username,String systemName,Long parentId){

		List<SysMenu> listMenus;
		/*第一级*/
		listMenus = menuDao.findMenusByUserName(username,systemName,parentId);
		if(listMenus != null && !listMenus.isEmpty()){
			for (SysMenu menu:listMenus) {
				setChildMenus(menu,username,systemName);
			}
		}
		return listMenus;
	}


	/**
	 * 递归
	 * @param sysMenu 菜单对象
	 * @param username 用户名
	 * @param systemName 系统名称
	 */
	private void setChildMenus(SysMenu sysMenu,String username,String systemName){
        List<SysMenu> result = menuDao.findMenusByUserName(username, systemName,sysMenu.getId());
        if(result != null && !result.isEmpty()){
            sysMenu.setSubMenus(result);
            for (SysMenu menu:result) {
                setChildMenus(menu,username,systemName);
            }
        }
    }

dao.java代码

/**
	 * 根据用户名username和系统systemName去查询菜单信息
	 * @param username
	 * @return
	 */
	List<SysMenu> findMenusByUserName(@Param("username")String username,@Param("systemName")String systemName,@Param("parentId")Long parentId);

<select id="findMenusByUserName" resultType="com.open.capacity.model.system.SysMenu">
		SELECT e.* from sys_user a
			LEFT JOIN sys_role_user b on a.id=b.userId
			LEFT JOIN sys_role c on c.id=b.roleId
			LEFT JOIN sys_role_menu d on d.roleId=c.id
			LEFT JOIN sys_menu e ON e.id=d.menuId
			LEFT JOIN sys_role_permission f ON f.roleId=c.id
			LEFT JOIN sys_permission g ON f.permissionId=g.id
			LEFT JOIN sys_system h ON h.id=g.systemId
			WHERE 1=1
			<if test="username!=null and username!=''">
				AND a.username=#{username}
			</if>
			<if test="systemName!=null and systemName!=''">
				AND h.name=#{systemName}
			</if>
			<if test="parentId == null"><!-- 如果父id没有值,默认查询第一层 -->
				AND e.parentId=-1
			</if>
			<if test="parentId != null and parentId != ''"><!-- 如果父id有值,则查询该父id下面的子id -->
				AND e.parentId=#{parentId}
			</if>
			AND e.id IS NOT NULL  GROUP BY e.id
	</select>