今日金句
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
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 <T>
*/
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 <T>
* @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 <T>
* @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
demo</div>
<!-- 头部区域（可配合layui 已有的水平导航） -->
<ul class="layui-nav layui-layout-left">
<!-- 移动端显示 -->
<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>
<!-- Top导航栏 -->
<li class="layui-nav-item layui-hide-xs"><a href="">nav 1</a></li>
<li class="layui-nav-item layui-hide-xs"><a href="">nav 2</a></li>
<li class="layui-nav-item layui-hide-xs"><a href="">nav 3</a></li>
<li class="layui-nav-item"><a href="javascript:;">nav
groups</a>
<dl class="layui-nav-child">
<dd>
<a href="">menu 11</a>
</dd>
<dd>
<a href="">menu 22</a>
</dd>
<dd>
<a href="">menu 33</a>
</dd>
</dl></li>
</ul>
<!-- 个人头像及账号操作 -->
<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 Profile</a>
</dd>
<dd>
<a href="">Settings</a>
</dd>
<dd>
<a href="login.jsp">Sign out</a>
</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">
<!-- 左侧导航区域（可配合layui已有的垂直导航） -->
<ul id="menu" class="layui-nav layui-nav-tree" lay-filter="menu">
<!-- <li class="layui-nav-item layui-nav-itemed">
<a class="" href="javascript:;">menu group 1</a>
<dl class="layui-nav-child">
<dd><a href="javascript:;">menu 1</a></dd>
<dd><a href="javascript:;">menu 2</a></dd>
<dd><a href="javascript:;">menu 3</a></dd>
<dd><a href="">the links</a></dd>
</dl>
</li> -->
</ul>
</div>
</div>
<div class="layui-body">
<!-- 内容主体区域 -->
<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 -->
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 += '<li class="layui-nav-item layui-nav-itemed">';
html += '<a class="" href="javascript:;">'+n.text+'</a>';
if (n.hasChildren) {
var children=n.children;
console.log(children);
html += ' <dl class="layui-nav-child">';
$.each(children,function(index,cn){
html += ' <dd><a href="javascript:;">'+cn.text+'</a></dd>';
})
html += ' </dl>';
}
html += '</li>';
});
$("#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: '<div style="padding: 15px;">处理右侧面板的操作</div>'
,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！文章来源：https://www.toymoban.com/news/detail-548701.html
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！！!
文章来源地址https://www.toymoban.com/news/detail-548701.html
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