权限控制之加载菜单栏（利用递归）

权限控制之加载树形表单

在我们平时做的项目中都有权限控制这个需求，其中菜单栏的展示是树形结构的，那么如何更好的把后台查到ode数据封装成树形结构呢，这篇文章我们来着重的介绍一下。利用递归来实现树形结构的展示。

首先来看一下表结构

从表结构中可以看出，可以根据id 和 pid 作为条件，将查询到的数据封装成树形结构

一、 加载树形菜单（递归）

通过代码实现加载树形结构的菜单栏

代码框架使用的 SpringBoot + mybatis_plus 实现的

（1） 控制层代码

//获取全部菜
//swagger 中的注解
    @ApiOperation(value = "查询所有菜单")
    @GetMapping
    public ResultVo indexAllPermission() {
        List<Permission> list =  permissionService.queryAllMenuGuli();
        return ResultVo.ok().data("children",list);
    }

（2） service 层(接口这里就不做声明了，直接贴上实现类)

/**
     * ========================递归查询所有菜单================================================
     * 获取全部菜单
     * @return
     */
    @Override
    public List<Permission> queryAllMenuGuli() {
        //1 查询菜单表所有数据
        QueryWrapper<Permission> wrapper = new QueryWrapper<>();
        //mybatis_plus 中封装的方法，根据id 进行排序查询
        wrapper.orderByDesc("id");
        List<Permission> permissionList = baseMapper.selectList(wrapper);
        //2 把查询所有菜单list集合按照要求进行封装
        List<Permission> resultList = bulidPermission(permissionList);
        return resultList;
    }

/**
     * @return
     * @Date 2020/8/3 23:27
     * @Author jiangheng
     * @Description //TODO 把返回所有菜单list集合进行封装的方法
     **/
    public static List<Permission> bulidPermission(List<Permission> permissionList) {

        //创建list集合，用于数据最终封装
        List<Permission> finalNode = new ArrayList<>();
        //把所有菜单list集合遍历，得到顶层菜单 pid=0菜单，设置level是1
        for(Permission permissionNode : permissionList) {
            //得到顶层菜单 pid=0菜单
            if("0".equals(permissionNode.getPid())) {
                //设置顶层菜单的level是1
                permissionNode.setLevel(1);
                //根据顶层菜单，向里面进行查询子菜单，封装到finalNode里面
                finalNode.add(selectChildren(permissionNode,permissionList));
            }
        }
        return finalNode;
    }

    /**
     * @return
     * @Date 2020/8/3 23:27
     * @Author jiangheng
     * @Description //TODO 查询子菜单，这里用到了递归
     **/
    private static Permission selectChildren(Permission permissionNode, List<Permission> permissionList) {
        //1 因为向一层菜单里面放二层菜单，二层里面还要放三层，把对象初始化
        permissionNode.setChildren(new ArrayList<Permission>());
        //2 遍历所有菜单list集合，进行判断比较，比较id和pid值是否相同
        for(Permission it : permissionList) {
            //判断 id和pid值是否相同
            if(permissionNode.getId().equals(it.getPid())) {
                //把父菜单的level值+1
                int level = permissionNode.getLevel()+1;
                it.setLevel(level);
                //如果children为空，进行初始化操作
                if(permissionNode.getChildren() == null) {
                    permissionNode.setChildren(new ArrayList<Permission>());
                }
                //把查询出来的子菜单放到父菜单里面
                permissionNode.getChildren().add(selectChildren(it,permissionList));
            }
        }
        return permissionNode;
    }

mapper 层这里不做声明了，都是调用的mybatis_plus 中的方法，感兴趣的可以自行百度mybatis_plus 官网，这里附上mybatis_plus 官网链接。
https://mp.baomidou.com/guide/

实体类

//这些注解感兴趣可以自行百度，也可以看我的博客。
@Data
@EqualsAndHashCode(callSuper = false)
@Accessors(chain = true)
@TableName("acl_permission")
@ApiModel(value="Permission对象", description="权限")
public class Permission implements Serializable {

    private static final long serialVersionUID = 1L;

    @ApiModelProperty(value = "编号")
    @TableId(value = "id", type = IdType.ID_WORKER_STR)
    private String id;

    @ApiModelProperty(value = "所属上级")
    private String pid;

    @ApiModelProperty(value = "名称")
    private String name;

    @ApiModelProperty(value = "类型(1:菜单,2:按钮)")
    private Integer type;

    @ApiModelProperty(value = "权限值")
    private String permissionValue;

    @ApiModelProperty(value = "访问路径")
    private String path;

    @ApiModelProperty(value = "组件路径")
    private String component;

    @ApiModelProperty(value = "图标")
    private String icon;

    @ApiModelProperty(value = "状态(0:禁止,1:正常)")
    private Integer status;

    @ApiModelProperty(value = "层级")
    @TableField(exist = false)
    private Integer level;

    @ApiModelProperty(value = "下级")
    @TableField(exist = false)
    private List<Permission> children;

    @ApiModelProperty(value = "是否选中")
    @TableField(exist = false)
    private boolean isSelect;


    @ApiModelProperty(value = "逻辑删除 1（true）已删除， 0（false）未删除")
    private Boolean isDeleted;

    @ApiModelProperty(value = "创建时间")
    private Date gmtCreate;

    @ApiModelProperty(value = "更新时间")
    private Date gmtModified;
}

二、 删除菜单 （递归）

这里只声明实现类。

//============递归删除菜单==================================
    @Override
    public void removeChildByIdGuli(String id) {
        //1 创建list集合，用于封装所有删除菜单id值
        List<String> idList = new ArrayList<>();
        //2 向idList集合设置删除菜单id
        this.selectPermissionChildById(id,idList);
        //把当前id封装到list里面
        idList.add(id);
        baseMapper.deleteBatchIds(idList);
    }

    //2 根据当前菜单id，查询菜单里面子菜单id，封装到list集合
    private void selectPermissionChildById(String id, List<String> idList) {
        //查询菜单里面子菜单id
        QueryWrapper<Permission>  wrapper = new QueryWrapper<>();
        wrapper.eq("pid",id);
        wrapper.select("id");
        List<Permission> childIdList = baseMapper.selectList(wrapper);
        //把childIdList里面菜单id值获取出来，封装idList里面，做递归查询
        childIdList.stream().forEach(item -> {
            //封装idList里面
            idList.add(item.getId());
            //递归查询
            this.selectPermissionChildById(item.getId(),idList);
        });
    }

最后附上表的sql，（仅仅为了你测试方便）

/*
 Navicat MySQL Data Transfer

 Source Server         : localhost
 Source Server Type    : MySQL
 Source Server Version : 80017
 Source Host           : localhost:3306
 Source Schema         : guli_acl

 Target Server Type    : MySQL
 Target Server Version : 80017
 File Encoding         : 65001

 Date: 03/08/2020 23:41:57
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for acl_permission
-- ----------------------------
DROP TABLE IF EXISTS `acl_permission`;
CREATE TABLE `acl_permission`  (
  `id` char(19) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT '编号',
  `pid` char(19) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT '所属上级',
  `name` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT '名称',
  `type` tinyint(3) NOT NULL DEFAULT 0 COMMENT '类型(1:菜单,2:按钮)',
  `permission_value` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '权限值',
  `path` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '访问路径',
  `component` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '组件路径',
  `icon` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '图标',
  `status` tinyint(4) NULL DEFAULT NULL COMMENT '状态(0:禁止,1:正常)',
  `is_deleted` tinyint(1) UNSIGNED NOT NULL DEFAULT 0 COMMENT '逻辑删除 1（true）已删除， 0（false）未删除',
  `gmt_create` datetime(0) NULL DEFAULT NULL COMMENT '创建时间',
  `gmt_modified` datetime(0) NULL DEFAULT NULL COMMENT '更新时间',
  PRIMARY KEY (`id`) USING BTREE,
  INDEX `idx_pid`(`pid`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci COMMENT = '权限' ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of acl_permission
-- ----------------------------
INSERT INTO `acl_permission` VALUES ('1', '0', '全部数据', 0, NULL, NULL, NULL, NULL, NULL, 0, '2019-11-15 17:13:06', '2019-11-15 17:13:06');
INSERT INTO `acl_permission` VALUES ('1195268474480156673', '1', '权限管理', 1, NULL, '/acl', 'Layout', NULL, NULL, 0, '2019-11-15 17:13:06', '2019-11-18 13:54:25');
INSERT INTO `acl_permission` VALUES ('1195268616021139457', '1195268474480156673', '用户管理', 1, NULL, 'user/list', '/acl/user/list', NULL, NULL, 0, '2019-11-15 17:13:40', '2019-11-18 13:53:12');
INSERT INTO `acl_permission` VALUES ('1195268788138598401', '1195268474480156673', '角色管理', 1, NULL, 'role/list', '/acl/role/list', NULL, NULL, 0, '2019-11-15 17:14:21', '2019-11-15 17:14:21');
INSERT INTO `acl_permission` VALUES ('1195268893830864898', '1195268474480156673', '菜单管理', 1, NULL, 'menu/list', '/acl/menu/list', NULL, NULL, 0, '2019-11-15 17:14:46', '2019-11-15 17:14:46');
INSERT INTO `acl_permission` VALUES ('1195269143060602882', '1195268616021139457', '查看', 2, 'user.list', '', '', NULL, NULL, 0, '2019-11-15 17:15:45', '2019-11-17 21:57:16');
INSERT INTO `acl_permission` VALUES ('1195269295926206466', '1195268616021139457', '添加', 2, 'user.add', 'user/add', '/acl/user/form', NULL, NULL, 0, '2019-11-15 17:16:22', '2019-11-15 17:16:22');
INSERT INTO `acl_permission` VALUES ('1195269473479483394', '1195268616021139457', '修改', 2, 'user.update', 'user/update/:id', '/acl/user/form', NULL, NULL, 0, '2019-11-15 17:17:04', '2019-11-15 17:17:04');
INSERT INTO `acl_permission` VALUES ('1195269547269873666', '1195268616021139457', '删除', 2, 'user.remove', '', '', NULL, NULL, 0, '2019-11-15 17:17:22', '2019-11-15 17:17:22');
INSERT INTO `acl_permission` VALUES ('1195269821262782465', '1195268788138598401', '修改', 2, 'role.update', 'role/update/:id', '/acl/role/form', NULL, NULL, 0, '2019-11-15 17:18:27', '2019-11-15 17:19:53');
INSERT INTO `acl_permission` VALUES ('1195269903542444034', '1195268788138598401', '查看', 2, 'role.list', '', '', NULL, NULL, 0, '2019-11-15 17:18:47', '2019-11-15 17:18:47');
INSERT INTO `acl_permission` VALUES ('1195270037005197313', '1195268788138598401', '添加', 2, 'role.add', 'role/add', '/acl/role/form', NULL, NULL, 0, '2019-11-15 17:19:19', '2019-11-18 11:05:42');
INSERT INTO `acl_permission` VALUES ('1195270442602782721', '1195268788138598401', '删除', 2, 'role.remove', '', '', NULL, NULL, 0, '2019-11-15 17:20:55', '2019-11-15 17:20:55');
INSERT INTO `acl_permission` VALUES ('1195270621548568578', '1195268788138598401', '角色权限', 2, 'role.acl', 'role/distribution/:id', '/acl/role/roleForm', NULL, NULL, 0, '2019-11-15 17:21:38', '2019-11-15 17:21:38');
INSERT INTO `acl_permission` VALUES ('1195270744097742849', '1195268893830864898', '查看', 2, 'permission.list', '', '', NULL, NULL, 0, '2019-11-15 17:22:07', '2019-11-15 17:22:07');
INSERT INTO `acl_permission` VALUES ('1195270810560684034', '1195268893830864898', '添加', 2, 'permission.add', '', '', NULL, NULL, 0, '2019-11-15 17:22:23', '2019-11-15 17:22:23');
INSERT INTO `acl_permission` VALUES ('1195270862100291586', '1195268893830864898', '修改', 2, 'permission.update', '', '', NULL, NULL, 0, '2019-11-15 17:22:35', '2019-11-15 17:22:35');
INSERT INTO `acl_permission` VALUES ('1195270887933009922', '1195268893830864898', '删除', 2, 'permission.remove', '', '', NULL, NULL, 0, '2019-11-15 17:22:41', '2019-11-15 17:22:41');
INSERT INTO `acl_permission` VALUES ('1195349439240048642', '1', '讲师管理', 1, NULL, '/edu/teacher', 'Layout', NULL, NULL, 0, '2019-11-15 22:34:49', '2019-11-15 22:34:49');
INSERT INTO `acl_permission` VALUES ('1195349699995734017', '1195349439240048642', '讲师列表', 1, NULL, 'list', '/edu/teacher/list', NULL, NULL, 0, '2019-11-15 22:35:52', '2019-11-15 22:35:52');
INSERT INTO `acl_permission` VALUES ('1195349810561781761', '1195349439240048642', '添加讲师', 1, NULL, 'create', '/edu/teacher/form', NULL, NULL, 0, '2019-11-15 22:36:18', '2019-11-15 22:36:18');
INSERT INTO `acl_permission` VALUES ('1195349876252971010', '1195349810561781761', '添加', 2, 'teacher.add', '', '', NULL, NULL, 0, '2019-11-15 22:36:34', '2019-11-15 22:36:34');
INSERT INTO `acl_permission` VALUES ('1195349979797753857', '1195349699995734017', '查看', 2, 'teacher.list', '', '', NULL, NULL, 0, '2019-11-15 22:36:58', '2019-11-15 22:36:58');
INSERT INTO `acl_permission` VALUES ('1195350117270261762', '1195349699995734017', '修改', 2, 'teacher.update', 'edit/:id', '/edu/teacher/form', NULL, NULL, 0, '2019-11-15 22:37:31', '2019-11-15 22:37:31');
INSERT INTO `acl_permission` VALUES ('1195350188359520258', '1195349699995734017', '删除', 2, 'teacher.remove', '', '', NULL, NULL, 0, '2019-11-15 22:37:48', '2019-11-15 22:37:48');
INSERT INTO `acl_permission` VALUES ('1195350299365969922', '1', '课程分类', 1, NULL, '/edu/subject', 'Layout', NULL, NULL, 0, '2019-11-15 22:38:15', '2019-11-15 22:38:15');
INSERT INTO `acl_permission` VALUES ('1195350397751758850', '1195350299365969922', '课程分类列表', 1, NULL, 'list', '/edu/subject/list', NULL, NULL, 0, '2019-11-15 22:38:38', '2019-11-15 22:38:38');
INSERT INTO `acl_permission` VALUES ('1195350500512206850', '1195350299365969922', '导入课程分类', 1, NULL, 'import', '/edu/subject/import', NULL, NULL, 0, '2019-11-15 22:39:03', '2019-11-15 22:39:03');
INSERT INTO `acl_permission` VALUES ('1195350612172967938', '1195350397751758850', '查看', 2, 'subject.list', '', '', NULL, NULL, 0, '2019-11-15 22:39:29', '2019-11-15 22:39:29');
INSERT INTO `acl_permission` VALUES ('1195350687590748161', '1195350500512206850', '导入', 2, 'subject.import', '', '', NULL, NULL, 0, '2019-11-15 22:39:47', '2019-11-15 22:39:47');
INSERT INTO `acl_permission` VALUES ('1195350831744782337', '1', '课程管理', 1, NULL, '/edu/course', 'Layout', NULL, NULL, 0, '2019-11-15 22:40:21', '2019-11-15 22:40:21');
INSERT INTO `acl_permission` VALUES ('1195350919074385921', '1195350831744782337', '课程列表', 1, NULL, 'list', '/edu/course/list', NULL, NULL, 0, '2019-11-15 22:40:42', '2019-11-15 22:40:42');
INSERT INTO `acl_permission` VALUES ('1195351020463296513', '1195350831744782337', '发布课程', 1, NULL, 'info', '/edu/course/info', NULL, NULL, 0, '2019-11-15 22:41:06', '2019-11-15 22:41:06');
INSERT INTO `acl_permission` VALUES ('1195351159672246274', '1195350919074385921', '完成发布', 2, 'course.publish', 'publish/:id', '/edu/course/publish', NULL, NULL, 0, '2019-11-15 22:41:40', '2019-11-15 22:44:01');
INSERT INTO `acl_permission` VALUES ('1195351326706208770', '1195350919074385921', '编辑课程', 2, 'course.update', 'info/:id', '/edu/course/info', NULL, NULL, 0, '2019-11-15 22:42:19', '2019-11-15 22:42:19');
INSERT INTO `acl_permission` VALUES ('1195351566221938690', '1195350919074385921', '编辑课程大纲', 2, 'chapter.update', 'chapter/:id', '/edu/course/chapter', NULL, NULL, 0, '2019-11-15 22:43:17', '2019-11-15 22:43:17');
INSERT INTO `acl_permission` VALUES ('1195351862889254913', '1', '统计分析', 1, NULL, '/statistics/daily', 'Layout', NULL, NULL, 0, '2019-11-15 22:44:27', '2019-11-15 22:44:27');
INSERT INTO `acl_permission` VALUES ('1195351968841568257', '1195351862889254913', '生成统计', 1, NULL, 'create', '/statistics/daily/create', NULL, NULL, 0, '2019-11-15 22:44:53', '2019-11-15 22:44:53');
INSERT INTO `acl_permission` VALUES ('1195352054917074946', '1195351862889254913', '统计图表', 1, NULL, 'chart', '/statistics/daily/chart', NULL, NULL, 0, '2019-11-15 22:45:13', '2019-11-15 22:45:13');
INSERT INTO `acl_permission` VALUES ('1195352127734386690', '1195352054917074946', '查看', 2, 'daily.list', '', '', NULL, NULL, 0, '2019-11-15 22:45:30', '2019-11-15 22:45:30');
INSERT INTO `acl_permission` VALUES ('1195352215768633346', '1195351968841568257', '生成', 2, 'daily.add', '', '', NULL, NULL, 0, '2019-11-15 22:45:51', '2019-11-15 22:45:51');
INSERT INTO `acl_permission` VALUES ('1195352547621965825', '1', 'CMS管理', 1, NULL, '/cms', 'Layout', NULL, NULL, 0, '2019-11-15 22:47:11', '2019-11-18 10:51:46');
INSERT INTO `acl_permission` VALUES ('1195352856645701633', '1195353513549205505', '查看', 2, 'banner.list', '', NULL, NULL, NULL, 0, '2019-11-15 22:48:24', '2019-11-15 22:48:24');
INSERT INTO `acl_permission` VALUES ('1195352909401657346', '1195353513549205505', '添加', 2, 'banner.add', 'banner/add', '/cms/banner/form', NULL, NULL, 0, '2019-11-15 22:48:37', '2019-11-18 10:52:10');
INSERT INTO `acl_permission` VALUES ('1195353051395624961', '1195353513549205505', '修改', 2, 'banner.update', 'banner/update/:id', '/cms/banner/form', NULL, NULL, 0, '2019-11-15 22:49:11', '2019-11-18 10:52:05');
INSERT INTO `acl_permission` VALUES ('1195353513549205505', '1195352547621965825', 'Bander列表', 1, NULL, 'banner/list', '/cms/banner/list', NULL, NULL, 0, '2019-11-15 22:51:01', '2019-11-18 10:51:29');
INSERT INTO `acl_permission` VALUES ('1195353672110673921', '1195353513549205505', '删除', 2, 'banner.remove', '', '', NULL, NULL, 0, '2019-11-15 22:51:39', '2019-11-15 22:51:39');
INSERT INTO `acl_permission` VALUES ('1195354076890370050', '1', '订单管理', 1, NULL, '/order', 'Layout', NULL, NULL, 0, '2019-11-15 22:53:15', '2019-11-15 22:53:15');
INSERT INTO `acl_permission` VALUES ('1195354153482555393', '1195354076890370050', '订单列表', 1, NULL, 'list', '/order/list', NULL, NULL, 0, '2019-11-15 22:53:33', '2019-11-15 22:53:58');
INSERT INTO `acl_permission` VALUES ('1195354315093282817', '1195354153482555393', '查看', 2, 'order.list', '', '', NULL, NULL, 0, '2019-11-15 22:54:12', '2019-11-15 22:54:12');
INSERT INTO `acl_permission` VALUES ('1196301740985311234', '1195268616021139457', '分配角色', 2, 'user.assgin', 'user/role/:id', '/acl/user/roleForm', NULL, NULL, 0, '2019-11-18 13:38:56', '2019-11-18 13:38:56');

SET FOREIGN_KEY_CHECKS = 1;