java實現(xiàn)遞歸菜單樹

更新時間：2020年08月26日 09:16:53 作者：男人要霸氣

這篇文章主要為大家詳細介紹了java實現(xiàn)遞歸菜單樹，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文實例為大家分享了java實現(xiàn)遞歸菜單樹的具體代碼，供大家參考，具體內(nèi)容如下

1.表結構

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for menu
-- ----------------------------
DROP TABLE IF EXISTS `menu`;
CREATE TABLE `menu` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `menu_name` varchar(64) NOT NULL COMMENT '菜單名稱',
 `order_num` int(11) DEFAULT NULL COMMENT '菜單順序',
 `url` varchar(64) DEFAULT NULL COMMENT '菜單路徑',
 `pid` varchar(11) DEFAULT NULL COMMENT '上級Id',
 `icon` varchar(255) DEFAULT NULL COMMENT '菜單圖標',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of menu
-- ----------------------------
INSERT INTO `menu` VALUES ('1', '系統(tǒng)管理', '1', '', '0', null);
INSERT INTO `menu` VALUES ('2', '軌跡查詢', '2', '', '0', null);
INSERT INTO `menu` VALUES ('3', '設備信息', '3', '', '0', null);
INSERT INTO `menu` VALUES ('4', '用戶信息', '1', '', '1', null);
INSERT INTO `menu` VALUES ('5', '客戶信息', '2', null, '1', null);
INSERT INTO `menu` VALUES ('6', '用戶資料', '1', null, '4', null);
INSERT INTO `menu` VALUES ('7', '客戶資料', '1', null, '5', null);
INSERT INTO `menu` VALUES ('8', '切割機', '1', null, '3', null);
INSERT INTO `menu` VALUES ('9', '鏟車', '2', null, '3', null);
INSERT INTO `menu` VALUES ('10', '割片', '1', null, '8', null);

2.菜單實體類

import lombok.Data;
import java.io.Serializable;
import java.util.List;
import javax.persistence.*;


/**
 *
 * @author m
 * @email 123456789@qq.com
 * @date 2019-12-13 16:54:59
 */
@Data
@Table(name = "menu")
public class Menu implements Serializable {
 private static final long serialVersionUID = 1L;
 
 //
 @Id
 private Integer id;
 
 //菜單名稱
 @Column(name = "menu_name")
 private String menuName;
 
 //菜單順序
 @Column(name = "order_num")
 private Integer orderNum;
 
 //菜單路徑
 @Column(name = "url")
 private String url;
 
 //上級Id
 @Column(name = "pid")
 private String pid;
 
 //菜單圖標
 @Column(name = "icon")
 private String icon;

 //子菜單
 @Transient
 private List<Menu> children;


}

3.菜單樹

 /**
  * 獲取菜單樹
  * @return
  */
 public List<Menu> menuTree() {
  //查詢所有菜單
  List<Menu> menus = mapper.selectAll();
  //返回的菜單樹
  List<Menu> rootMenus = new ArrayList<>();
  for (Menu menu : menus) {
   //pid（上級Id）為0的是根菜單
   if ("0".equals(menu.getPid())) {
    rootMenus.add(menu);
   }
  }
  //遍歷，找到二級菜單（根菜單的id和所有菜單中的pid比較）
  for (Menu rootMenu : rootMenus) {
   List<Menu> child = getChild(String.valueOf(rootMenu.getId()), menus);
   rootMenu.setChildren(child);
  }
  return rootMenus;
 }


 /**
  * 遞歸獲取下級菜單
  * @param pid 上級Id
  * @param menus 所有菜單
  * @return
  */
 public List<Menu> getChild(String pid, List<Menu> menus) {
  //子菜單列表
  List<Menu> childList = new ArrayList<>();
  for (Menu menu : menus) {
   if (pid.equals(menu.getPid())) {
    childList.add(menu);
   }
  }
  //遍歷 獲取子菜單的子菜單
  for (Menu menu : childList) {
   List<Menu> child = getChild(String.valueOf(menu.getId()), menus);
   menu.setChildren(child);
  }
  //遞歸出口 childList長度為0
  if (childList.size() == 0) {
   return new ArrayList<>();
  }
  return childList;
 }

4.測試

{
 "status": 200,
 "message": "操作成功",
 "data": [
  {
   "id": 1,
   "menuName": "系統(tǒng)管理",
   "orderNum": 1,
   "url": "",
   "pid": "0",
   "icon": null,
   "children": [
    {
     "id": 4,
     "menuName": "用戶信息",
     "orderNum": 1,
     "url": "",
     "pid": "1",
     "icon": null,
     "children": [
      {
       "id": 6,
       "menuName": "用戶資料",
       "orderNum": 1,
       "url": null,
       "pid": "4",
       "icon": null,
       "children": []
      }
     ]
    },
    {
     "id": 5,
     "menuName": "客戶信息",
     "orderNum": 2,
     "url": null,
     "pid": "1",
     "icon": null,
     "children": [
      {
       "id": 7,
       "menuName": "客戶資料",
       "orderNum": 1,
       "url": null,
       "pid": "5",
       "icon": null,
       "children": []
      }
     ]
    }
   ]
  },
  {
   "id": 2,
   "menuName": "軌跡查詢",
   "orderNum": 2,
   "url": "",
   "pid": "0",
   "icon": null,
   "children": []
  },
  {
   "id": 3,
   "menuName": "設備信息",
   "orderNum": 3,
   "url": "",
   "pid": "0",
   "icon": null,
   "children": [
    {
     "id": 8,
     "menuName": "切割機",
     "orderNum": 1,
     "url": null,
     "pid": "3",
     "icon": null,
     "children": [
      {
       "id": 10,
       "menuName": "割片",
       "orderNum": 1,
       "url": null,
       "pid": "8",
       "icon": null,
       "children": []
      }
     ]
    },
    {
     "id": 9,
     "menuName": "鏟車",
     "orderNum": 2,
     "url": null,
     "pid": "3",
     "icon": null,
     "children": []
    }
   ]
  }
 ]
}

5.菜單樹工具類

菜單樹工具類

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