Gorm 实现无限树形菜单

原文链接：https://www.zhoubotong.site/post/91.html
通常树形菜单的实现基本就是递归调用，大部分场景毕竟这种数据不多，性能倒是并不突出， 下面给个demo,有兴趣的朋友可以看看： 新建一个city表：

CREATE TABLE `city` (  `id` int NOT NULL AUTO_INCREMENT,  `pid` int NOT NULL DEFAULT '0' COMMENT '父级别id',  `name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '0' COMMENT '名称',  PRIMARY KEY (`id`) USING BTREE,  KEY `pid` (`pid`) USING BTREE) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

测试数据：

INSERT INTO `city` (`id`, `pid`, `name`) VALUES (1, 0, '广东省');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (2, 1, '广州市');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (3, 2, '广州天河区');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (4, 2, '海珠区');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (5, 0, '福建省');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (6, 5, '厦门市');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (7, 4, '新港');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (8, 4, '沙园');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (9, 7, '新港一区');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (10, 0, '湖北省');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (11, 10, '武汉市');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (12, 11, '黄陂区');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (13, 11, '洪山区');INSERT INTO `city` (`id`, `pid`, `name`) VALUES (14, 12, '黄陂天河街道');

demo.go：

package mainimport (    "encoding/json"    "fmt"    "gorm.io/driver/mysql"    "gorm.io/gorm")var DB gorm.DBfunc (u TreeNode) TableName() string {    return "city"}type TreeNode struct {    Id       int         `json:"id"`    Pid      int         `json:"pid" gorm:"index"`    Name     string      `json:"name" gorm:"size:255"`    Children []*TreeNode `json:"children" gorm:"-"`}func init() {    dsn := "root:uos123456@tcp(11213:3306)/demo?charset=utf8mb4&parseTime=True&loc=Local"    db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})    if err != nil {        panic("failed to connect database")    }    DB = *db}func main() {    data := TreeList(10) // 查询武汉市下的子节点    str, _ := json.Marshal(data)    fmt.Printf("%s\\n", str)}// TreeList 递归处理子节点listfunc TreeList(pid int) []*TreeNode {    var list []*TreeNode    DB.Model(TreeNode{}).Where("pid= ?", pid).Find(&list)    result := make([]*TreeNode, 0)    for _, v := range list {        if v.Pid == pid {            v.Children = TreeList(v.Id)            if v.Children == nil {                v.Children = make([]*TreeNode, 0)            }            result = append(result, v)        }    }    return result}

输出结果：

[Running] go run "/media/uos/G/web/demo-go/demo.go"[{"id":11,"pid":10,"name":"武汉市","children":[{"id":12,"pid":11,"name":"黄陂区","children":[{"id":14,"pid":12,"name":"黄陂天河街道","children":[]}]},{"id":13,"pid":11,"name":"洪山区","children":[]}]}]

无论从事什么行业，只要做好两件事就够了，一个是你的专业、一个是你的人品，专业决定了你的存在，人品决定了你的人脉，剩下的就是坚持，用善良專業和真诚赢取更多的信任。