代码语言：javascript复制项目做完了，可以有时间写写博客了。 今天给大家讲解一下layui的三级动态加载菜单含后端代码。
我是最近刚学的layui，非常感谢贤心大神。开发出这么牛逼ui的框架。
声明：KingYiFan前段是渣渣，本次讲解用的前端js并非KingYiFan亲自封装只是稍作修改，非常感谢封装三级菜单CSDN的大神：yufengaotian 下图就是三级菜单效果。为什么要讲这个呢。
yufenggaotian大神也在博客中写道这个问题我就借用一下：
（图来着yufenggaotianCSDN博客）
代码语言：javascript复制前端页面：
//直接上代码吧
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<title>三级菜单展示</title>
</head>
<body>
<div class="layui-side layui-bg-black" id="admin-side">
<div class="layui-side-scroll">
<ul class="layui-nav layui-nav-tree" id="nav" lay-filter="demo"></ul>
</div>
</div>
</body>
<link rel="stylesheet" href="/static/css/layui.css">
<script src="/static/js/jquery.js" type="text/javascript" charset="utf-8"></script>
<script src="/static/lib/layui/layui.js"></script>
<script src="/static/js/api.js"></script>
<script>
//监听选中页签添加样式
layui.config({
base: '/static/lib/layui/' //navbar组件js所在目录
}).use('navbar', function() {
var navbar = layui.navbar();
navbar.set({
elem: '#nav',
url: "/menuInfo" //访问后台接口
});
navbar.render();
//给选中的页签添加选中样式（解决刷新失效问题）
var url = window.location.href.replace("//", "");
var relUrl = url.substring(url.lastIndexOf("/") 1);
//去掉参数部分
if (relUrl.indexOf("?") != -1) {
relUrl = relUrl.split("?")[0];
}
$("#leftNavbar a").each(function () {
var that = this;
if ($(that).attr("href") == relUrl) {
$(that).parent().addClass("layui-this");
$(that).parents("li:eq(0)").addClass("layui-nav-itemed");
var nodes = $(that).parents("li:eq(0)").find("a .layui-nav-more");
if (nodes.length > 0) {
nodes.each(function () {
if ($(this).parents("dd:eq(0)").find("[href='" relUrl
"']").length > 0) {
$(this).parent().parent().addClass("layui-nav-itemed");
}
});
}
}
});
});
</script>
</html>js部分可以不做修改
layui.define(['element', 'common'], function (exports) {
"use strict";
var $ = layui.jquery,
layer = parent.layer === undefined ? layui.layer : parent.layer,
element = layui.element,
common = layui.common,
cacheName = 'tb_navbar';
var Navbar = function () {
/**
* 默认配置
*/
this.config = {
elem: undefined, //容器
data: undefined, //数据源
url: undefined, //数据源地址
type: 'GET', //读取方式
cached: false, //是否使用缓存
spreadOne: false //设置是否只展开一个二级菜单
};
this.v = '1.0.0';
};
//渲染
Navbar.prototype.render = function () {
var _that = this;
var _config = _that.config;
if (typeof (_config.elem) !== 'string' && typeof (_config.elem) !== 'object') {
common.throwError('Navbar error: elem参数未定义或设置出错，具体设置格式请参考文档API.');
}
var $container;
if (typeof (_config.elem) === 'string') {
$container = $('' _config.elem '');
}
if (typeof (_config.elem) === 'object') {
$container = _config.elem;
}
if ($container.length === 0) {
common.throwError('Navbar error:找不到elem参数配置的容器，请检查.');
}
if (_config.data === undefined && _config.url === undefined) {
common.throwError('Navbar error:请为Navbar配置数据源.')
}
if (_config.data !== undefined && typeof (_config.data) === 'object') {
var html = getHtml(_config.data);
$container.html(html);
element.init();
_that.config.elem = $container;
} else {
if (_config.cached) {
var cacheNavbar = layui.data(cacheName);
if (cacheNavbar.navbar === undefined) {
$.ajax({
type: _config.type,
url: _config.url,
async: false, //_config.async,
dataType: 'json',
success: function (result, status, xhr) {
//添加缓存
layui.data(cacheName, {
key: 'navbar',
value: result
});
var html = getHtml(result);
$container.html(html);
element.init();
},
error: function (xhr, status, error) {
common.msgError('Navbar error:' error);
},
complete: function (xhr, status) {
_that.config.elem = $container;
}
});
} else {
var html = getHtml(cacheNavbar.navbar);
$container.html(html);
element.init();
_that.config.elem = $container;
}
} else {
//清空缓存
layui.data(cacheName, null);
$.ajax({
type: _config.type,
url: _config.url,
async: false, //_config.async,
dataType: 'json',
success: function (result, status, xhr) {
var html = getHtml(result);
$container.html(html);
element.init();
},
error: function (xhr, status, error) {
common.msgError('Navbar error:' error);
},
complete: function (xhr, status) {
_that.config.elem = $container;
}
});
}
}
//只展开一个二级菜单
if (_config.spreadOne) {
var $ul = $container.children('ul');
$ul.find('li.layui-nav-item').each(function () {
$(this).on('click', function () {
$(this).siblings().removeClass('layui-nav-itemed');
});
});
}
return _that;
};
/**
* 配置Navbar
* @param {Object} options
*/
Navbar.prototype.set = function (options) {
var that = this;
that.config.data = undefined;
$.extend(true, that.config, options);
return that;
};
/**
* 绑定事件
* @param {String} events
* @param {Function} callback
*/
Navbar.prototype.on = function (events, callback) {
var that = this;
var _con = that.config.elem;
if (typeof (events) !== 'string') {
common.throwError('Navbar error:事件名配置出错，请参考API文档.');
}
var lIndex = events.indexOf('(');
var eventName = events.substr(0, lIndex);
var filter = events.substring(lIndex 1, events.indexOf(')'));
if (eventName === 'click') {
if (_con.attr('lay-filter') !== undefined) {
_con.children('ul').find('li').each(function () {
var $this = $(this);
if ($this.find('dl').length > 0) {
var $dd = $this.find('dd').each(function () {
$(this).on('click', function () {
var $a = $(this).children('a');
var href = $a.data('url');
var icon = $a.children('i:first').data('icon');
var title = $a.children('cite').text();
var data = {
elem: $a,
field: {
href: href,
icon: icon,
title: title
}
}
callback(data);
});
});
} else {
$this.on('click', function () {
var $a = $this.children('a');
var href = $a.data('url');
var icon = $a.children('i:first').data('icon');
var title = $a.children('cite').text();
var data = {
elem: $a,
field: {
href: href,
icon: icon,
title: title
}
}
callback(data);
});
}
});
}
}
};
/**
* 清除缓存
*/
Navbar.prototype.cleanCached = function () {
layui.data(cacheName, null);
};
/**
* 获取html字符串
* @param {Object} data
*/
function getHtml(data) {
var ulHtml = '<ul class="layui-nav layui-nav-tree beg-navbar">';
for (var i = 0; i < data.length; i ) {
if (data[i].spread) {
ulHtml = '<li class="layui-nav-item layui-nav-itemed">';
} else {
ulHtml = '<li class="layui-nav-item">';
}
if (data[i].children !== undefined && data[i].children !== null && data[i].children.length > 0) {
ulHtml = '<a href="javascript:;">' data[i].title;
ulHtml = '<span class="layui-nav-more"></span>';
ulHtml = '</a>';
ulHtml = '<dl class="layui-nav-child">';
//二级菜单
for (var j = 0; j < data[i].children.length; j ) {
//是否有孙子节点
if (data[i].children[j].children !== undefined && data[i].children[j].children !== null && data[i].children[j].children.length > 0) {
ulHtml = '<dd>';
ulHtml = '<a href="javascript:;">' data[i].children[j].title;
ulHtml = '<span class="layui-nav-more"></span>';
ulHtml = '</a>';
//三级菜单
ulHtml = '<dl class="layui-nav-child">';
var grandsonNodes = data[i].children[j].children;
for (var k = 0; k < grandsonNodes.length; k ) {
ulHtml = '<dd>';
ulHtml = '<a target="xq" href="' grandsonNodes[k].href '">' grandsonNodes[k].title '</a>';
ulHtml = '</dd>';
}
ulHtml = '</dl>';
ulHtml = '</dd>';
}else{
ulHtml = '<dd>';
ulHtml = '<a target="xq" href="' data[i].children[j].href '">' data[i].children[j].title;
ulHtml = '</a>';
ulHtml = '</dd>';
}
//ulHtml = '<dd title="' data[i].children[j].title '">';
}
ulHtml = '</dl>';
} else {
var dataUrl = (data[i].href !== undefined && data[i].href !== '') ? 'data-url="' data[i].href '"' : '';
//ulHtml = '<a href="javascript:;" ' dataUrl '>';
ulHtml = '<a href="' data[i].href '"' dataUrl 'target="xq">';
if (data[i].icon !== undefined && data[i].icon !== '') {
ulHtml = '<i class="layui-icon" >' '<img src=' data[i].icon '>' '</i>';
}
ulHtml = '<cite>' data[i].title '</cite>';
ulHtml = '</a>';
}
ulHtml = '</li>';
}
ulHtml = '</ul>';
return ulHtml;
}
var navbar = new Navbar();
exports('navbar', function (options) {
return navbar.set(options);
});
});
common.js
layui.define(['layer'], function(exports) {
"use strict";
var $ = layui.jquery,
layer = layui.layer;
var common = {
/**
* 抛出一个异常错误信息
* @param {String} msg
*/
throwError: function(msg) {
throw new Error(msg);
return;
},
/**
* 弹出一个错误提示
* @param {String} msg
*/
msgError: function(msg) {
layer.msg(msg, {
icon: 5
});
return;
}
};
exports('common', common);
});json格式：
[
{
"title": "我是一级",
"icon": "",
"spread": true,
"href": "",
"children": [
{
"title": "我是二级",
"icon": "",
"href": "",
"spread": true,
"children": [
{
"title": "我是三级",
"icon": " ",
"href": "https://cnbuilder.cn/"
},
{
"title": "我也是三级",
"icon": " ",
"href": "https://cnbuilder.cn/"
}
]
}
]
}
]代码语言：javascript复制java代码部分 1、用到了MyBatisPlus技术 2、用到了Lombok 所以代码量很少
controller：
/**
* 1、根据用户id查询角色
* 2、遍历角色查询资源
* KingYiFan create By 2019/03/14
* @return
*/
@GetMapping("/menuInfo")
@ResponseBody
public Object menuInfo() {
if (getShiroUser().getId() == null) {
return "redirect:/login";
}
//查询用户的菜单
List<BsResource> bsResources = bsRoleService.selectMenuByUserId(getShiroUser().getId());
//根据菜单封装需要的格式
List<BsResource> trees = TreeBuilder.bulid(bsResources);
return trees;
}service接口
@Override
public List<BsResource> selectMenuByUserId(Long userId) {
//根据用户id查询所有角色
List<Long> roleIdList = bsTenantRoleMapper.selectRoleIdListByTenantId(userId);
Set<String> urlSet = new HashSet<String>();
//遍历全部角色
for (Long roleId : roleIdList) {
//根据角色获取当前资源
List<Map<String, String>> resourceList = bsRoleMapper.selectResourceListByRoleId(roleId);
for (Map<String, String> map : resourceList) {
urlSet.add(map.get("id"));
}
}
//根据id查询菜单
List<BsResource> bsResources = bsResourceMapper.selectBatchIds(urlSet);
return bsResources;
}代码语言：javascript复制实体类
package cn.cnbuilder.entity;
import com.baomidou.mybatisplus.annotations.TableField;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.hcr.model.BaseEntity;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.experimental.Accessors;
import java.util.List;
/**
* <p>
* 资源表 这个是全局的资源表
* </p>
*
* @author KingYiFan
* @since 2019-03-14
*/
@Data
@EqualsAndHashCode(callSuper = true)
@Accessors(chain = true)
public class BsResource {
private static final long serialVersionUID = 1L;
private Long id;
@TableField(exist = false)
private List<BsResource> children;
/**
* 资源名称
*/
private String title;
/**
* 资源路径
*/
private String href;
/**
* 资源介绍
*/
private String description;
/**
* 资源图标
*/
private String icon;
/**
* 父级资源id
*/
@TableField(value = "p_id")
private Integer pId;
/**
* 排序
*/
private String seq;
/**
* 状态
*/
private Integer status;
/**
* 打开状态
*/
private Integer spread;
/**
* 资源类别
*/
private Integer resourceType;
}代码语言：javascript复制工具类
package cn.cnbuilder.utils;
import cn.cnbuilder.entity.BsResource;
import java.util.List;
import java.util.ArrayList;
import java.util.List;
/**
* Created by KingYiFan on 2019/03/14.
*/
public class TreeBuilder {
/**
* 两层循环实现建树
*
* @param BsResources 传入的树节点列表
* @return
*/
public static List<BsResource> bulid(List<BsResource> BsResources) {
List<BsResource> trees = new ArrayList<BsResource>();
for (BsResource BsResource : BsResources) {
if (BsResource.getPId()==0) {
trees.add(BsResource);
}
for (BsResource it : BsResources) {
if (it.getPId() == BsResource.getId().intValue()) {
if (BsResource.getChildren() == null) {
BsResource.setChildren(new ArrayList<BsResource>());
}
BsResource.getChildren().add(it);
}
}
}
return trees;
}
/**
* 使用递归方法建树
*
* @param BsResources
* @return
*/
public static List<BsResource> buildByRecursive(List<BsResource> BsResources) {
List<BsResource> trees = new ArrayList<BsResource>();
for (BsResource BsResource : BsResources) {
if ("0".equals(BsResource.getPId())) {
trees.add(findChildren(BsResource, BsResources));
}
}
return trees;
}
/**
* 递归查找子节点
*
* @param BsResources
* @return
*/
public static BsResource findChildren(BsResource BsResource, List<BsResource> BsResources) {
for (BsResource it : BsResources) {
if (BsResource.getId().equals(it.getPId())) {
if (BsResource.getChildren() == null) {
BsResource.setChildren(new ArrayList<BsResource>());
}
BsResource.getChildren().add(findChildren(it, BsResources));
}
}
return BsResource;
}
public static void main(String[] args) {
List<BsResource> list = new ArrayList<BsResource>();
List<BsResource> trees = TreeBuilder.bulid(list);
List<BsResource> trees_ = TreeBuilder.buildByRecursive(list);
}
}这就是layui动态三级菜单渲染。有什么不懂的可以跟我联系。
感谢一路支持我的人。。。。。
Love me and hold me
QQ:69673804（16年老号）
EMAIL:69673804@qq.com
友链交换
如果有兴趣和本博客交换友链的话，请按照下面的格式在评论区进行评论，我会尽快添加上你的链接。网站名称：KingYiFan’S Blog
网站地址：http://blog.cnbuilder.cn
网站描述：年少是你未醒的梦话，风华是燃烬的彼岸花。
网站Logo/头像： [头像地址](https://blog.cnbuilder.cn/upload/2018/7/avatar20180720144536200.jpg)
