Java中树形菜单分析和实现
一、背景概述
- 最近在搭建基于Spring Boot(2.0.2)种子项目框架时，遇到了树形菜单加载问题。特此把解决的问题方案记录下去，供其他小伙伴参考和日后回顾。
二、方案分析
- 方案选择
- 一次性加载完，返回前台需要的数据结构
- 点击加载，默认记载根层级的菜单。后续点击那一级菜单加载其下的子节点
- 方案实现
- 在这里只分析一次性加载实现。第二种实现起来更简单。在这里略过。有兴趣可以自己研究一下。
三、具体实现
-
表、对象设计
- 表结构
- 测试数据（忽略内容==）
- 对象字段
private String informationTypeId; // 菜单id private Integer informationTypeNum; private String informationTypeCode; private String informationTypeUrl; private String informationTypeName; private String informationTypePicBosKey; private Integer informationTypeLevel; private String type; private String model; private Boolean isEdit; private String parentId; // 父菜单id private String remark; private String createUserId; private Date createTime; private String modifyUserId; private Date modifyTime; private Date timeStamp; private ListchildNodes = new ArrayList<>(); // 子菜单list // 省略set,get - 查出所有菜单列表
- 表结构
/**
* 查询资讯菜单（一次性加载）
*
* @throws CustomException
*/
@RequestMapping(value = "/findAllTypeList")
public List findAllTypeList() throws CustomException {
// 加载所有菜单列表
// 根级的菜单列表
List rootList = informationTypeService.findInfoTypeByType("1", null);
List list = new ArrayList<>();
for (int i = 0; i < rootList.size(); i++) {
InformationTypeEntity typeEntity = rootList.get(i);
if ("-1".equals(typeEntity.getParentId())) {
list.add(typeEntity);
}
}
for (InformationTypeEntity entity : list) {
entity.setChildNodes(getChildNodes(entity.getInformationTypeId(), rootList));
}
return list;
}
- 找出根节点菜单列表
/**
* 查询资讯菜单（一次性加载）
*
* @throws CustomException
*/
@RequestMapping(value = "/findAllTypeList")
public List findAllTypeList() throws CustomException {
List rootList = informationTypeService.findInfoTypeByType("1", null);
List list = new ArrayList<>();
for (int i = 0; i < rootList.size(); i++) {
InformationTypeEntity typeEntity = rootList.get(i);
// 找出根级菜单，（约定所有根级菜单的parentId属性为-1）
if ("-1".equals(typeEntity.getParentId())) {
list.add(typeEntity);
}
}
for (InformationTypeEntity entity : list) {
entity.setChildNodes(getChildNodes(entity.getInformationTypeId(), rootList));
}
return list;
}
- 循环找出每个子节点的菜单列表
/**
* 查询资讯菜单（一次性加载）
*
* @throws CustomException
*/
@RequestMapping(value = "/findAllTypeList")
public List findAllTypeList() throws CustomException {
List rootList = informationTypeService.findInfoTypeByType("1", null);
List list = new ArrayList<>();
for (int i = 0; i < rootList.size(); i++) {
InformationTypeEntity typeEntity = rootList.get(i);
// 找出根级菜单，（约定所有根级菜单的parentId属性为-1）
if ("-1".equals(typeEntity.getParentId())) {
list.add(typeEntity);
}
}
// 循环根级菜单，为每个根级菜单下的子菜单list赋值。
for (InformationTypeEntity entity : list) {
entity.setChildNodes(getChildNodes(entity.getInformationTypeId(), rootList));
}
return list;
}
- 递归解决无限层级嵌套（里面的注释我写的很清楚。大概的思路就是除了当前子菜单后，还要考虑子菜单的子菜单，考虑用递归处理。递归结束的条件就是没有子菜单，也就是list的size为0.此种方式支持无线的嵌套）
/**
* Return the list of children node from percent menu id
*
* @param id current menu id
* @param rootList all list of menus
* @return
* @throws CustomException
*/
private List getChildNodes(String id, List rootList) throws CustomException {
// The list of child nodes
List childList = new ArrayList<>();
// Fill the list of child'nodes which parent id equal params of id
for (InformationTypeEntity typeEntity : rootList) {
if (StringUtils.isNotBlank(typeEntity.getParentId())) {
if (id.equals(typeEntity.getParentId())) {
childList.add(typeEntity);
}
}
}
if (childList.size() == 0) {
return null;
}
// Look up it's child node and fill
for (InformationTypeEntity entity : childList) {
entity.setChildNodes(getChildNodes(entity.getInformationTypeId(), rootList));
}
return childList;
}
四、总结
- 关于树形菜单的实现方案有很多，我只是列举出比较典型的2种方案。
- 举例的这种方案可以支持无限级嵌套
- 举例的这种只发送一次sql,可以在一定程度上调高效率，减少数据库压力
- 理解思路，上面的代码好看优化哈，以后有时间再补充上
五、测试结果返回的数据结果示例如下 （数组中包含多个对象，对象里面嵌套子节点集合…）
其实这样的数据结构会满足大部分前端树形组件的数据结构的要求。
前台菜单形如下图：
后端返回的结果如下结构：
[
{
"informationTypeId": "4",
"informationTypeNum": 1,
"informationTypeCode": "001",
"informationTypeUrl": "/index",
"informationTypeName": "资讯管理",
"informationTypePicBosKey": "pic",
"informationTypeLevel": null,
"type": "1",
"model": "1",
"isEdit": null,
"parentId": "-1",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 10:17:51",
"childNodes": [
{
"informationTypeId": "1",
"informationTypeNum": 1,
"informationTypeCode": "001001",
"informationTypeUrl": "/index1",
"informationTypeName": "十九大管理",
"informationTypePicBosKey": "pic1",
"informationTypeLevel": null,
"type": "1",
"model": "1",
"isEdit": null,
"parentId": "4",
"remark": null,
"createUserId": null,
"createTime": "2018-06-01 10:15:35",
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 10:17:56",
"childNodes": [
{
"informationTypeId": "5",
"informationTypeNum": 1,
"informationTypeCode": "001001001",
"informationTypeUrl": "/index/index1",
"informationTypeName": "中国梦",
"informationTypePicBosKey": "pic",
"informationTypeLevel": null,
"type": "1",
"model": "2",
"isEdit": null,
"parentId": "1",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 10:18:53",
"childNodes": [
{
"informationTypeId": "8",
"informationTypeNum": 1,
"informationTypeCode": "001001001001",
"informationTypeUrl": "/index/index/index",
"informationTypeName": "白日梦",
"informationTypePicBosKey": "pic",
"informationTypeLevel": null,
"type": "1",
"model": "1",
"isEdit": null,
"parentId": "5",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 11:21:50",
"childNodes": [
{
"informationTypeId": "10",
"informationTypeNum": 1,
"informationTypeCode": "001001001001001",
"informationTypeUrl": "/index/index/index2",
"informationTypeName": "李白的白日梦",
"informationTypePicBosKey": "pic",
"informationTypeLevel": null,
"type": "1",
"model": "1",
"isEdit": null,
"parentId": "8",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 11:24:05",
"childNodes": [
{
"informationTypeId": "12",
"informationTypeNum": 1,
"informationTypeCode": "000013123123123123123",
"informationTypeUrl": "12341234123123",
"informationTypeName": "李白的白日梦儿子1",
"informationTypePicBosKey": "23213",
"informationTypeLevel": null,
"type": "1",
"model": "1",
"isEdit": null,
"parentId": "10",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 11:32:36",
"childNodes": [
{
"informationTypeId": "14",
"informationTypeNum": 2,
"informationTypeCode": "242424",
"informationTypeUrl": "24243234234",
"informationTypeName": "l李白的白日梦儿子1的儿子11111",
"informationTypePicBosKey": "2424",
"informationTypeLevel": null,
"type": "1",
"model": "2",
"isEdit": null,
"parentId": "12",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 11:36:28",
"childNodes": null
}
]
},
{
"informationTypeId": "13",
"informationTypeNum": 2,
"informationTypeCode": "2424234234234234",
"informationTypeUrl": "2424242424",
"informationTypeName": "李白的白日梦儿子2",
"informationTypePicBosKey": "23424",
"informationTypeLevel": null,
"type": "1",
"model": "1",
"isEdit": null,
"parentId": "10",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 11:33:07",
"childNodes": null
}
]
},
{
"informationTypeId": "11",
"informationTypeNum": 2,
"informationTypeCode": "0010001001001002",
"informationTypeUrl": "/index/index/index2",
"informationTypeName": "杜甫的白日梦",
"informationTypePicBosKey": "pic",
"informationTypeLevel": null,
"type": "1",
"model": "2",
"isEdit": null,
"parentId": "8",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 11:24:58",
"childNodes": null
}
]
},
{
"informationTypeId": "9",
"informationTypeNum": 2,
"informationTypeCode": "001001001002",
"informationTypeUrl": "/index/index/index2",
"informationTypeName": "黑夜梦",
"informationTypePicBosKey": "pic",
"informationTypeLevel": null,
"type": "1",
"model": "2",
"isEdit": null,
"parentId": "5",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 11:22:30",
"childNodes": null
}
]
},
{
"informationTypeId": "6",
"informationTypeNum": 2,
"informationTypeCode": "001001002",
"informationTypeUrl": "/index/index2",
"informationTypeName": "扶贫",
"informationTypePicBosKey": "pic",
"informationTypeLevel": null,
"type": "1",
"model": "2",
"isEdit": null,
"parentId": "1",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 10:20:23",
"childNodes": null
}
]
},
{
"informationTypeId": "2",
"informationTypeNum": 2,
"informationTypeCode": "001002",
"informationTypeUrl": "/index2",
"informationTypeName": "党代会议管理",
"informationTypePicBosKey": "pic2",
"informationTypeLevel": null,
"type": "1",
"model": "2",
"isEdit": null,
"parentId": "4",
"remark": null,
"createUserId": null,
"createTime": "2018-06-13 05:48:42",
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 10:17:54",
"childNodes": [
{
"informationTypeId": "7",
"informationTypeNum": 1,
"informationTypeCode": "001002001",
"informationTypeUrl": "/index/index",
"informationTypeName": "党会管理",
"informationTypePicBosKey": "pic111",
"informationTypeLevel": null,
"type": "1",
"model": "3",
"isEdit": null,
"parentId": "2",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 10:20:59",
"childNodes": null
}
]
},
{
"informationTypeId": "3",
"informationTypeNum": 3,
"informationTypeCode": "001003",
"informationTypeUrl": "/index3",
"informationTypeName": "两学一做",
"informationTypePicBosKey": "pic3",
"informationTypeLevel": null,
"type": "1",
"model": "1",
"isEdit": null,
"parentId": "4",
"remark": null,
"createUserId": null,
"createTime": null,
"modifyUserId": null,
"modifyTime": null,
"timeStamp": "2018-06-15 10:17:53",
"childNodes": null
}
]
}
]