Java递归实现菜单树的方法详解

Java递归实现菜单树的方法详解

pom文件

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

4.0.0

org.springframework.boot

spring-boot-starter-parent

2.1.3.RELEASE

com.example

demo

0.0.1-SNAPSHOT

demo

Demo project for Spring Boot

1.8

org.springframework.boot

spring-boot-starter

org.springframework.boot

spring-boot-starter-web

org.springframework.boot

spring-boot-starter-thymeleaf

org.springframework.boot

spring-boot-starter-test

test

org.mybatis.spring.boot

mybatis-spring-boot-starter

2.1.1

mysql

mysql-connector-java

runtime

com.github.pagehelper

pagehelper-spring-boot-starter

1.3.0

org.projectlombok

lombok

true

com.baomidou

mybatis-plus-boot-starter

3.4.2

org.springframework.boot

spring-boot-maven-plugin

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

4.0.0

org.springframework.boot

spring-boot-starter-parent

2.1.3.RELEASE

com.example

demo

0.0.1-SNAPSHOT

demo

Demo project for Spring Boot

1.8

org.springframework.boot

spring-boot-starter

org.springframework.boot

spring-boot-starter-web

org.springframework.boot

spring-boot-starter-thymeleaf

org.springframework.boot

spring-boot-starter-test

test

org.mybatis.spring.boot

mybatis-spring-boot-starter

2.1.1

mysql

mysql-connector-java

runtime

com.github.pagehelper

pagehelper-spring-boot-starter

1.3.0

org.projectlombok

lombok

true

com.baomidou

mybatis-plus-boot-starter

3.4.2

org.springframework.boot

spring-boot-maven-plugin

application.yaml文件

spring:

datasource:

url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&serverTimezone=CTT

username: root

password: 2020

driver-class-name: com.mysql.cj.jdbc.Driver

pagehelper:

helperDialect: mysql

reasonable: true # 修改默认值

# mybatis-plus配置

mybatis-plus:

configuration:

log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

typeAliasesPackage: com.qcby.entity

mapperLocations: classpath:mapper/*.xml

# 全局配置id自增 =>

global-config:

db-config:

id-type: auto

数据库表设计如下

SET NAMES utf8mb4;

SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------

-- Table structure for menu

-- ----------------------------

DROP TABLE IF EXISTS `menu`;

CREATE TABLE `menu` (

`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键id',

`name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin DEFAULT NULL COMMENT '名称',

`pid` bigint(20) DEFAULT NULL COMMENT '父级id',

PRIMARY KEY (`id`) USING BTREE

) ENGINE = InnoDB AUTO_INCREMENT = 10 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin ROW_FORMAT = Compact;

-- ----------------------------

-- Records of menu

-- ----------------------------

INSERT INTO `menu` VALUES (1, '主菜单1', 0);

INSERT INTO `menu` VALUES (2, '主菜单2', 0);

INSERT INTO `menu` VALUES (3, '主菜单3', 0);

INSERT INTO `menu` VALUES (4, '菜单1.1', 1);

INSERT INTO `menu` VALUES (5, '菜单1.2', 1);

INSERT INTO `menu` VALUES (6, '菜单1.1.1', 4);

INSERT INTO `menu` VALUES (7, '菜单2.1', 2);

INSERT INTO `menu` VALUES (8, '菜单2.2', 2);

INSERT INTO `menu` VALUES (9, '菜单1.1.2', 4);

SET FOREIGN_KEY_CHECKS = 1;

菜单类

package com.qcby.entity;

import lombok.Data;

import java.util.List;

@Data//lombok实现简化 get、set、tostring方法

public class Menu {

// 菜单id

private String id;

//菜单名称

private String name;

// 父菜单id

private String pid;

// 子菜单

private List

}

xml文件

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

SELECT * FROM menu WHERE pid=#{pid}

SELECT * FROM menu

SELECT * FROM menu where pid!= 0

Mapper层

package com.qcby.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;

import com.qcby.entity.Menu;

import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper

public interface MenuMapper extends BaseMapper

List

List

List

}

service层

package com.qcby.service;

import com.baomidou.mybatisplus.extension.service.IService;

import com.qcby.entity.Menu;

import java.util.List;

public interface MenuService extends IService

List

List

List

}

serviceImpl

package com.qcby.service.ImplFrdavmCS;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;

import com.qcby.entity.Menu;

import com.qcby.mapper.MenuMapper;

import com.qcby.service.MenuService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import java.util.List;

@Service

public class MenuServiceImpl extends ServiceImpl implements MenuService {

@Autowired

private MenuMapper menuMapper;

@Override

public List

return menuMapper.selectByPid(pid);

}

@Override

public List

return menuMapper.selectAll();

}

@Override

public List

return menuMapper.selectAllNotBase();

}

}

controller层

package com.qcby.controller;

import com.baomidou.mybatisplus.core.toolkit.StringUtils;

import com.qcby.entity.Menu;

import com.qcby.mapper.MenuMapper;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;

import java.util.List;

@RestController

@RequestMapping("menu")

public class MenuController {

@Autowired

private MenuMapper menuMapper;

@RequestMapping("/getMenuTree")

public List

List

List

for (Menu menu : menusBase) {

List

menu.setMenuChildren(menus);

}

return menusBase;

}

/**

*多级菜单查询方法

* @param menuVoList 不包含最高层次菜单的菜单集合

* @param pid 父类id

* @return

*/

public List

List

for (Menu menu : menuVoList) {

//获取菜单的id

String menuid = menu.getId();

//获取菜单的父id

String parentid = menu.getPid();

if(StringUtils.isNotBlank(parentid)){

if(parentid.equals(pid)){

//递归查询当前子菜单的子菜单

List

menu.setMenuChildren(iterateMenu);

result.add(menu);

}

}

}

return result;

}

}

结果展示

总结

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