layui实现左侧导航树形菜单

今日金句

战术上的勤奋并不能掩盖战略上的懒惰

文章目录

  • 前言
  • 一、左侧导航
    • 1.1 概述
    • 1.2 树形菜单
  • 二、导入数据表及无限级分类
    • 2.1 导入数据
    • 2.2 无限级分类
  • 三、Book实例
    • 3.1 环境准备
    • 3.3 导入封装的工具类
    • 3.3 实体类及dao方法的编写
    • 3.4 编写Servlet
    • 3.5 编写Jsp

前言

在上篇博客中,我们学习了layui的入门,还实现了后台的登陆注册,今天我们就来完成后台首页的重要组成部分——左侧导航树形菜单

一、左侧导航

1.1 概述

  • 导航一般指页面引导性频道集合,多以菜单的形式呈现,可应用于头部和侧边,是整个网页画龙点晴般的存在。 面包屑结构简单,支持自定义分隔符。

1.2 树形菜单

概述

  • 树形菜单是一种常见的界面组件,用于在网页或应用程序中呈现层级结构的菜单。它通常以树的形式展示,其中每个节点表示一个菜单项,节点之间的嵌套关系表示菜单项的层级关系。

  • 树形菜单适用于具有多级层次结构的菜单导航,例如文件浏览器、系统设置、产品分类等。它的主要优点是能够清晰地显示和组织大量的菜单选项,并且用户可以通过展开和折叠节点来快速浏览和选择适当的菜单项。

一般而言,树形菜单的基本特点包括

  • 节点可以展开和折叠,以显示或隐藏其子菜单项。
  • 子菜单项嵌套在父菜单项下面,形成层级结构。
  • 点击菜单项可以执行相应的操作或导航到指定的页面。
  • 提供了一种直观的方式来浏览和导航具有层级关系的菜单选项。

注:千万不要忘了加载 element模块。虽然大部分行为都是在加载完该模块后自动完成的,但一些交互操作,
如呼出二级菜单等,需借助element模块才能使用。

参考地址:layui导航

二、导入数据表及无限级分类

2.1 导入数据

DROP TABLE IF EXISTS `t_easyui_permission`;
CREATE TABLE `t_easyui_permission`  (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '权限id',
  `name` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '权限名字',
  `description` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '权限描述',
  `url` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '菜单路径',
  `pid` bigint(20) NULL DEFAULT NULL COMMENT '父权限',
  `ismenu` int(11) NULL DEFAULT 1 COMMENT '是否为菜单 1、菜单  2、按钮',
  `displayno` bigint(20) NULL DEFAULT 0 COMMENT '展现顺序',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 16 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of t_easyui_permission
-- ----------------------------
INSERT INTO `t_easyui_permission` VALUES (1, '书籍管理', '书籍管理', NULL, 0, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (2, '新增(crud)', '书籍新增', '/bg/addBook.jsp', 1, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (3, '未上架', '未上架书籍', '/bg/listBook1.jsp', 1, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (4, '已上架', '已上架书籍', '/bg/listBook2.jsp', 1, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (5, '已下架', '已下架书籍', '/bg/listBook3.jsp', 1, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (6, '订单管理', '商家的订单管理模块', NULL, 0, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (7, '未发货', '未发货订单', '/bg/listOrder1.jsp', 6, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (8, '已发货', '已发货订单', '/bg/listOrder2.jsp', 6, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (9, '已签收', '已签收订单', '/bg/listOrder3.jsp', 6, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (10, '订单管理', '会员的订单管理模块', '', 0, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (11, '未发货', '未发货订单', '/bg/listMyOrder1.jsp', 10, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (12, '已发货', '已发货订单', '/bg/listMyOrder2.jsp', 10, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (13, '已签收', '已签收订单', '/bg/listMyOrder3.jsp', 10, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (14, '订单项', '订单明细', '/bg/listOrderItem.jsp', 6, 1, 0);
INSERT INTO `t_easyui_permission` VALUES (15, '权限管理', '顶级权限节点', NULL, -1, 1, 0);

2.2 无限级分类

父亲找儿子的过程,将对应的儿子放在父亲下面,形成树结构。(递归算法)
假设你有以下的无限级分类数据源:

var data = [
  { id: 1, name: '父亲1', parentId: null },
  { id: 2, name: '父亲2', parentId: null },
  { id: 3, name: '儿子1', parentId: 1 },
  { id: 4, name: '儿子2', parentId: 1 },
  { id: 5, name: '孙子1', parentId: 3 },
  { id: 6, name: '孙子2', parentId: 3 },
  { id: 7, name: '儿子3', parentId: 2 }
];

使用以下递归函数来构建树结构:

function buildTree(data, parentId) {
  var children = [];
  for (var i = 0; i < data.length; i++) {
    if (data[i].parentId === parentId) {
      var child = {
        id: data[i].id,
        name: data[i].name,
        children: buildTree(data, data[i].id)
      };
      children.push(child);
    }
  }
  return children;
}

调用函数以构建树结构:

var tree = buildTree(data, null);
console.log(tree);

三、Book实例

layui实现左侧导航树形菜单_第1张图片

3.1 环境准备

各种jar包、配置文件的导入在这里我就不介绍了,想看的请到上篇博客layui入门+登入注册实例

3.3 导入封装的工具类

TreeVo

package com.zking.util;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

 /**树形结构的节点对象
 * @author W许潜行
 * @param 
 */
public class TreeVo<T> {
	/**
	 * 节点ID
	 */
	private String id;
	/**
	 * 显示节点文本
	 */
	private String text;
	/**
	 * 节点状态,open closed
	 */
	private Map<String, Object> state;
	/**
	 * 节点是否被选中 true false
	 */
	private boolean checked = false;
	/**
	 * 节点属性
	 */
	private Map<String, Object> attributes;

	/**
	 * 节点的子节点
	 */
	private List<TreeVo<T>> children = new ArrayList<TreeVo<T>>();

	/**
	 * 父ID
	 */
	private String parentId;
	/**
	 * 是否有父节点
	 */
	private boolean hasParent = false;
	/**
	 * 是否有子节点
	 */
	private boolean hasChildren = false;

	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}

	public String getText() {
		return text;
	}

	public void setText(String text) {
		this.text = text;
	}

	public Map<String, Object> getState() {
		return state;
	}

	public void setState(Map<String, Object> state) {
		this.state = state;
	}

	public boolean isChecked() {
		return checked;
	}

	public void setChecked(boolean checked) {
		this.checked = checked;
	}

	public Map<String, Object> getAttributes() {
		return attributes;
	}

	public void setAttributes(Map<String, Object> attributes) {
		this.attributes = attributes;
	}

	public List<TreeVo<T>> getChildren() {
		return children;
	}

	public void setChildren(List<TreeVo<T>> children) {
		this.children = children;
	}

	public boolean isHasParent() {
		return hasParent;
	}

	public void setHasParent(boolean isParent) {
		this.hasParent = isParent;
	}

	public boolean isHasChildren() {
		return hasChildren;
	}

	public void setChildren(boolean isChildren) {
		this.hasChildren = isChildren;
	}

	public String getParentId() {
		return parentId;
	}

	public void setParentId(String parentId) {
		this.parentId = parentId;
	}

	public TreeVo(String id, String text, Map<String, Object> state, boolean checked, Map<String, Object> attributes,
                  List<TreeVo<T>> children, boolean isParent, boolean isChildren, String parentID) {
		super();
		this.id = id;
		this.text = text;
		this.state = state;
		this.checked = checked;
		this.attributes = attributes;
		this.children = children;
		this.hasParent = isParent;
		this.hasChildren = isChildren;
		this.parentId = parentID;
	}

	public TreeVo() {
		super();
	}

}

BuildTree

package com.zking.util;                                                                                                             
                                                                                                                                    
import java.util.ArrayList;                                                                                                         
import java.util.HashMap;                                                                                                           
import java.util.List;                                                                                                              
import java.util.Map;                                                                                                               
                                                                                                                                    
public class BuildTree {                                                                                                            
                                                                                                                                    
	/**                                                                                                                             
	 * 默认-1为顶级节点                                                                                                                    
	 * @param nodes                                                                                                                 
	 * @param                                                                                                                    
	 * @return                                                                                                                      
	 */                                                                                                                             
	public static <T> TreeVo<T> build(List<TreeVo<T>> nodes) {                                                                      
                                                                                                                                    
		if (nodes == null) {                                                                                                        
			return null;                                                                                                            
		}                                                                                                                           
		List<TreeVo<T>> topNodes = new ArrayList<TreeVo<T>>();                                                                      
                                                                                                                                    
		for (TreeVo<T> children : nodes) {                                                                                          
			String pid = children.getParentId();                                                                                    
			if (pid == null || "-1".equals(pid)) {                                                                                  
				topNodes.add(children);                                                                                             
                                                                                                                                    
				continue;                                                                                                           
			}                                                                                                                       
                                                                                                                                    
			for (TreeVo<T> parent : nodes) {                                                                                        
				String id = parent.getId();                                                                                         
				if (id != null && id.equals(pid)) {                                                                                 
					parent.getChildren().add(children);                                                                             
					children.setHasParent(true);                                                                                    
					parent.setChildren(true);                                                                                       
					continue;                                                                                                       
				}                                                                                                                   
			}                                                                                                                       
                                                                                                                                    
		}                                                                                                                           
                                                                                                                                    
		TreeVo<T> root = new TreeVo<T>();                                                                                           
		if (topNodes.size() == 1) {                                                                                                 
			root = topNodes.get(0);                                                                                                 
		} else {                                                                                                                    
			root.setId("000");                                                                                                      
			root.setParentId("-1");                                                                                                 
			root.setHasParent(false);                                                                                               
			root.setChildren(true);                                                                                                 
			root.setChecked(true);                                                                                                  
			root.setChildren(topNodes);                                                                                             
			root.setText("顶级节点");                                                                                                   
			Map<String, Object> state = new HashMap<>(16);                                                                          
			state.put("opened", true);                                                                                              
			root.setState(state);                                                                                                   
		}                                                                                                                           
                                                                                                                                    
		return root;                                                                                                                
	}                                                                                                                               
                                                                                                                                    
	/**                                                                                                                             
	 * 指定idparam为顶级节点                                                                                                               
	 * @param nodes                                                                                                                 
	 * @param idParam                                                                                                               
	 * @param                                                                                                                    
	 * @return                                                                                                                      
	 */                                                                                                                             
	public static <T> List<TreeVo<T>> buildList(List<TreeVo<T>> nodes, String idParam) {                                            
		if (nodes == null) {                                                                                                        
			return null;                                                                                                            
		}                                                                                                                           
		List<TreeVo<T>> topNodes = new ArrayList<TreeVo<T>>();                                                                      
                                                                                                                                    
		for (TreeVo<T> children : nodes) {                                                                                          
                                                                                                                                    
			String pid = children.getParentId();                                                                                    
			if (pid == null || idParam.equals(pid)) {                                                                               
				topNodes.add(children);                                                                                             
                                                                                                                                    
				continue;                                                                                                           
			}                                                                                                                       
                                                                                                                                    
			for (TreeVo<T> parent : nodes) {                                                                                        
				String id = parent.getId();                                                                                         
				if (id != null && id.equals(pid)) {                                                                                 
					parent.getChildren().add(children);                                                                             
					children.setHasParent(true);                                                                                    
					parent.setChildren(true);                                                                                       
                                                                                                                                    
					continue;                                                                                                       
				}                                                                                                                   
			}                                                                                                                       
                                                                                                                                    
		}                                                                                                                           
		return topNodes;                                                                                                            
	}                                                                                                                               
                                                                                                                                    
}                                                                                                                                   

3.3 实体类及dao方法的编写

entity

package com.xqx.entity;

/**
 * @author W许潜行
 * 2023年7月12日 上午9:43:11
 */
public class Book {
	/**
	 * 权限id 
	 * 权限名字 
	 * 权限描述 
	 * 菜单路径 
	 * 父权限 
	 * 是否为菜单 1、菜单 2、
	 * 按钮 
	 * 展现顺序
	 */
	private long id;
	private String name;
	private String description;
	private String url;
	private long pid;
	private int ismenu;
	private long displayno;
	public Book() {
		// TODO Auto-generated constructor stub
	}
	public Book(long id, String name, String description, String url, long pid, int ismenu, long displayno) {
		super();
		this.id = id;
		this.name = name;
		this.description = description;
		this.url = url;
		this.pid = pid;
		this.ismenu = ismenu;
		this.displayno = displayno;
	}
	@Override
	public String toString() {
		return "Book [id=" + id + ", name=" + name + ", description=" + description + ", url=" + url + ", pid=" + pid
				+ ", ismenu=" + ismenu + ", displayno=" + displayno + "]";
	}
	public long getId() {
		return id;
	}
	public void setId(long id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getDescription() {
		return description;
	}
	public void setDescription(String description) {
		this.description = description;
	}
	public String getUrl() {
		return url;
	}
	public void setUrl(String url) {
		this.url = url;
	}
	public long getPid() {
		return pid;
	}
	public void setPid(long pid) {
		this.pid = pid;
	}
	public int getIsmenu() {
		return ismenu;
	}
	public void setIsmenu(int ismenu) {
		this.ismenu = ismenu;
	}
	public long getDisplayno() {
		return displayno;
	}
	public void setDisplayno(long displayno) {
		this.displayno = displayno;
	}
	

}

Dao

package com.xqx.dao;

import java.util.ArrayList;
import java.util.List;

import com.xqx.entity.Book;
import com.zking.util.BaseDao;
import com.zking.util.BuildTree;
import com.zking.util.PageBean;
import com.zking.util.TreeVo;

public class BookDao extends BaseDao<Book> {
	/**拿到所有数据
	 * @param clz
	 * @param pageBean
	 * @return
	 * @throws Exception
	 */
	public List<Book> list(Class<Book> clz, PageBean pageBean) throws Exception {
		String sql ="select *from t_easyui_permission";
		return super.executeQuery(sql, clz, pageBean);
	}
	/**将list()查出的数据——平级数据(一级)转成父子关系数据——二级菜单
	 * @param clz
	 * @param pageBean
	 * @return
	 * @throws Exception
	 */
	public List<TreeVo<Book>> menus(Class<Book> clz, PageBean pageBean) throws Exception {
		List<TreeVo<Book>> list=new ArrayList<TreeVo<Book>>();
		List<Book> blist = this.list(clz, pageBean);
		Book b=new Book();
		for (Book book : blist) {
			TreeVo<Book> vo=new TreeVo<>();
			vo.setId(book.getId()+"");
			vo.setText(book.getName());
			vo.setParentId(book.getPid()+"");
			list.add(vo);
		}
		return BuildTree.buildList(list,"0");
	}

3.4 编写Servlet

package com.xqx.web;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.xqx.dao.BookDao;
import com.xqx.entity.Book;
import com.zking.framework.ActionSupport;
import com.zking.framework.ModelDriver;
import com.zking.util.ResponseUtil;
import com.zking.util.TreeVo;

public class BookAction extends ActionSupport implements ModelDriver<Book> {
	Book book=new Book();
	BookDao bd=new BookDao();
	public void menus(HttpServletRequest req, HttpServletResponse resp) {
		try {
			List<TreeVo<Book>> menus = bd.menus(Book.class, null);
			ResponseUtil.writeJson(resp, menus);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	@Override
	public Book getModel() {
		// TODO Auto-generated method stub
		return book;
	}

}

3.5 编写Jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
DOCTYPE html>
<html>
<%@ include file="common/head.jsp"%>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>首页title>
head>
<body>
	<div class="layui-layout layui-layout-admin">
		<div class="layui-header">
			<div class="layui-logo layui-hide-xs layui-bg-black">layout
				demodiv>
			
			<ul class="layui-nav layui-layout-left">
				
				<li class="layui-nav-item layui-show-xs-inline-block layui-hide-sm"
					lay-header-event="menuLeft"><i
					class="layui-icon layui-icon-spread-left">i>li>
				
				<li class="layui-nav-item layui-hide-xs"><a href="">nav 1a>li>
				<li class="layui-nav-item layui-hide-xs"><a href="">nav 2a>li>
				<li class="layui-nav-item layui-hide-xs"><a href="">nav 3a>li>
				<li class="layui-nav-item"><a href="javascript:;">nav
						groupsa>
					<dl class="layui-nav-child">
						<dd>
							<a href="">menu 11a>
						dd>
						<dd>
							<a href="">menu 22a>
						dd>
						<dd>
							<a href="">menu 33a>
						dd>
					dl>li>
			ul>
			
			<ul class="layui-nav layui-layout-right">
				<li class="layui-nav-item layui-hide layui-show-md-inline-block">
					<a href="javascript:;"> <img
						src="//tva1.sinaimg.cn/crop.0.0.118.118.180/5db11ff4gw1e77d3nqrv8j203b03cweg.jpg"
						class="layui-nav-img"> tester
				a>
					<dl class="layui-nav-child">
						<dd>
							<a href="">Your Profilea>
						dd>
						<dd>
							<a href="">Settingsa>
						dd>
						<dd>
							<a href="login.jsp">Sign outa>
						dd>
					dl>
				li>
				<li class="layui-nav-item" lay-header-event="menuRight" lay-unselect>
					<a href="javascript:;"> <i
						class="layui-icon layui-icon-more-vertical">i>
				a>
				li>
			ul>
		div>

		<div class="layui-side layui-bg-black">
			<div class="layui-side-scroll">
				
				<ul id="menu" class="layui-nav layui-nav-tree" lay-filter="menu">

				ul>
			div>
		div>

		<div class="layui-body">
			
			<div style="padding: 15px;">内容主体区域。记得修改 layui.css 和 js 的路径——许潜行div>
		div>

		<div class="layui-footer">
			
			底部固定区域
		div>
	div>
	<script>
//JS 
layui.use(['element', 'layer', 'util'], function(){
  var element = layui.element
  ,layer = layui.layer
  ,util = layui.util
  ,$ = layui.$;
  $.ajax({
	  url:"${pageContext.request.contextPath }/book.action?methodName=menus",
      dataType:'json',
      success:function(data){
    	  var html='';
    	  $.each(data,function(i,n){
    		  html += '
  • '; html += ''+n.text+''; if (n.hasChildren) { var children=n.children; console.log(children); html += '
    '; $.each(children,function(index,cn){ html += '
    '+cn.text+'
    '
    ; }) html += '
    '
    ; } html += '
  • '
    ; }); $("#menu").html(html); element.render('menu'); } }); //头部事件 util.event('lay-header-event', { //左侧菜单事件 menuLeft: function(othis){ layer.msg('展开左侧菜单的操作', {icon: 0}); } ,menuRight: function(){ layer.open({ type: 1 ,content: '
    处理右侧面板的操作
    '
    ,area: ['260px', '100%'] ,offset: 'rt' //右上角 ,anim: 5 ,shadeClose: true }); } }); });
    script> body> html>

    其实埋了一个小伏笔哦,这张表有爷子孙的关系也就是可以实现三级菜单,想知道的小伙伴可以私信留言或者等下篇博客!

    好啦,本篇分享就到此为止!如果你看完本篇文章有所收获,请不要忘记点个赞,或者留下你的思考与问题,祝你变得更强!!!

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