CREATE DATABASE bootdb;

CREATE TABLE `t_class`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `class` varchar(50) CHARACTER SET utf8 DEFAULT NULL,
  `boys` int(11) DEFAULT NULL,
  `girls` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8;

INSERT INTO `t_class` VALUES (1, '20軟件1班', 26, 18);
INSERT INTO `t_class` VALUES (2, '20軟件2班', 17, 20);
INSERT INTO `t_class` VALUES (3, '20大數據1班', 24, 30);
INSERT INTO `t_class` VALUES (4, '20計應2班', 21, 24);

package net.huawei.echarts.bean;

/**
 * 功能：班級實體類
 * 作者：華衛(wèi)
 * 日期：2022年06月15日
 */
public class Clazz {
    private int id;
    private String clazz;
    private int boys;
    private int girls;

    public int getId() {
        return id;
    }

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

    public String getClazz() {
        return clazz;
    }

    public void setClazz(String clazz) {
        this.clazz = clazz;
    }

    public int getBoys() {
        return boys;
    }

    public void setBoys(int boys) {
        this.boys = boys;
    }

    public int getGirls() {
        return girls;
    }

    public void setGirls(int girls) {
        this.girls = girls;
    }

    @Override
    public String toString() {
        return "Clazz{" +
                "id=" + id +
                ", clazz='" + clazz + '\'' +
                ", boys=" + boys +
                ", girls=" + girls +
                '}';
    }
}

package net.huawei.echarts.mapper;

import net.huawei.echarts.bean.Clazz;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

/**
 * 功能：班級映射器接口
 * 作者：華衛(wèi)
 * 日期：2022年06月15日
 */
@Mapper
public interface ClazzMapper {
    List<Clazz> findAll();
}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="net.huawei.echarts.mapper.ClazzMapper">
    <!--定義結果映射，因為表字段名與實體屬性名不完全一致-->
    <resultMap id="clazzMap" type="net.huawei.echarts.bean.Clazz">
        <result property="id" column="id"/>
        <result property="clazz" column="class"/>
        <result property="boys" column="boys"/>
        <result property="girls" column="girls"/>
    </resultMap>

    <select id="findAll" resultMap="clazzMap">
        SELECT * FROM t_class;
    </select>
</mapper>

package net.huawei.echarts.service;

import net.huawei.echarts.bean.Clazz;
import net.huawei.echarts.mapper.ClazzMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * 功能：班級服務類
 * 作者：華衛(wèi)
 * 日期：2022年06月15日
 */
@Service
public class ClazzService {
    @Autowired(required = false)
    private ClazzMapper clazzMapper;

    public List<Clazz> findAll() {
        return clazzMapper.findAll();
    }
}

package net.huawei.echarts.controller;

import net.huawei.echarts.bean.Clazz;
import net.huawei.echarts.service.ClazzService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.List;

/**
 * 功能：班級控制器
 * 作者：華衛(wèi)
 * 日期：2022年06月15日
 */
@Controller
public class ClazzController {
    @Autowired
    private ClazzService clazzService;

    @GetMapping("/")
    public String index() {
        return "index";
    }

    @RequestMapping(value = "/getAll", produces = "application/json; charset=utf-8")
    @ResponseBody
    public List<Clazz> getAll() {
        List<Clazz> clazzes = clazzService.findAll();
        return clazzes;
    }
}

<dependency>
     <groupId>com.alibaba</groupId>
     <artifactId>druid-spring-boot-starter</artifactId>
     <version>1.2.11</version>
</dependency>

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/bootdb?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF-8
    username: root
    password: 903213

    type: com.alibaba.druid.pool.DruidDataSource
    druid:
      initial-size: 20
      max-active: 100
      min-idle: 10

mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: net.huawei.echarts.bean
  
server:
  port: 8888

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>20級各班人數柱狀圖</title>
    <script src="js/jquery.min.js"></script>
    <script src="js/echarts.min.js"></script>
    <style>
        .box {
            width: 600px;
            height: 400px;
            border: 1px solid cornflowerblue;
        }
    </style>
</head>
<body>
<input type="button" value="顯示柱狀圖" class="btnShowBar"/>
<hr/>
<div class="box"></div>
<script>
    // 獲取box元素
    var box = document.getElementsByClassName("box")[0];
    // 獲取btnShowBar元素
    var btnShowBar = document.getElementsByClassName("btnShowBar")[0];
    // 定義按鈕單擊事件
    btnShowBar.onclick = function () {
        // 獲取后臺返回的JSON數據
        $.get('/getAll', function (data) {
            // 定義三個數組
            class_list = [];
            boy_list = [];
            girl_list = [];

            // 將json數據寫入數組
            for (var i = 0; i < data.length; i++) {
                class_list.push(data[i].clazz);
                boy_list.push(data[i].boys);
                girl_list.push(data[i].girls);
            }

            // 1. 初始化ECharts
            var my_box = echarts.init(box);

            // 2. 進行參數配置
            var option = {
                // 標題
                title: {
                    text: "20級各班人數柱狀圖",
                    x: "center",
                    y: "top",
                    textAlign: "left",
                    textStyle: {
                        fontFamily: "楷體",
                        fontSize: 35,
                        textStyle: "bold"
                    }
                },

                // 圖例
                legend: {
                    left: "right",
                    orient: "vertical"
                },

                // x軸數據
                xAxis: {
                    data: class_list
                },

                // y軸數據
                yAxis: {},

                // 數據信息
                series: [
                    {
                        name: "男生人數",
                        type: "bar",
                        data: boy_list,
                        itemStyle: {
                            normal: {
                                color: '#0000aa'
                            }
                        }
                    },
                    {
                        name: "女生人數",
                        type: "bar",
                        data: girl_list,
                        itemStyle: {
                            normal: {
                                color: '#aa0000'
                            }
                        }
                    }
                ]
            }

            // 3. 可視化呈現
            my_box.setOption(option);
        });
    }
</script>
</body>
</html>