编写一段springboot代码，纯后端导出Excel,excel中包含数据列表和echarts统计图

好的，下面是一份使用poi和echarts实现的纯后端导出Excel的示例代码：

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.*;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

@Controller
@RequestMapping("/export")
public class ExcelExportController {

    @RequestMapping(value = "/excel", method = RequestMethod.GET)
    @ResponseBody
    public String exportExcel() {

        // 构造数据列表
        List<User> userList = new ArrayList<>();
        userList.add(new User("张三", 18, "男"));
        userList.add(new User("李四", 20, "女"));
        userList.add(new User("王五", 22, "男"));
        userList.add(new User("赵六", 24, "女"));

        // 初始化 Excel 文档
        XSSFWorkbook workbook = new XSSFWorkbook();
        XSSFSheet sheet = workbook.createSheet("用户信息");

        // 创建表头
        XSSFRow headerRow = sheet.createRow(0);
        headerRow.createCell(0).setCellValue("姓名");
        headerRow.createCell(1).setCellValue("年龄");
        headerRow.createCell(2).setCellValue("性别");

        // 填充数据
        int rowNum = 1;
        for (User user : userList) {
            XSSFRow row = sheet.createRow(rowNum++);
            row.createCell(0).setCellValue(user.getName());
            row.createCell(1).setCellValue(user.getAge());
            row.createCell(2).setCellValue(user.getGender());
        }

        // 添加图表
        XSSFDrawing drawing = sheet.createDrawingPatriarch();
        XSSFClientAnchor anchor = drawing.createAnchor(0, 0, 0, 0, 4, 1, 15, 20);
        XSSFSheet chartSheet = workbook.createSheet("统计图");
        XSSFChart chart = drawing.createChart(anchor);
        XSSFChartLegend legend = chart.getOrCreateLegend();
        legend.setPosition(LegendPosition.TOP_RIGHT);
        XSSFChartAxis xAxis = chart.getChartAxisFactory().createCategoryAxis(AxisPosition.BOTTOM);
        XSSFValueAxis yAxis = chart.getChartAxisFactory().createValueAxis(AxisPosition.LEFT);
        yAxis.setCrosses(AxisCrosses.AUTO_ZERO);
        List<String> xData = new ArrayList<>();
        List<Double> yData = new ArrayList<>();
        xData.add("张三");
        xData.add("李四");
        xData.add("王五");
        xData.add("赵六");
        yData.add(18.0);
        yData.add(20.0);
        yData.add(22.0);
        yData.add(24.0);
        XSSFChartSeries series = chart.createSeries();
        series.setTitle("年龄统计");
        XSSFDataSheet xDataSheet = chartSheet.createDataSheet();
        XSSFChartData data = chart.getChartDataFactory().createBarChartData();
        XSSFChartAxis bottomAxis = chart.getChartAxisFactory().createCategoryAxis(AxisPosition.BOTTOM);
        XSSFValueAxis leftAxis = chart.getChartAxisFactory().createValueAxis(AxisPosition.LEFT);
        ChartDataSource<String> xDataSource = DataSources.fromStringCellRange(sheet, new CellRangeAddress(1, 4, 0, 0));
        ChartDataSource<Number> yDataSource = DataSources.fromNumericCellRange(sheet, new CellRangeAddress(1, 4, 1, 1));
        series = data.addSeries(xDataSource, yDataSource);
        chart.plot(data, bottomAxis, leftAxis);

        // 输出 Excel 文件
        try (FileOutputStream outputStream = new FileOutputStream("users.xlsx")) {
            workbook.write(outputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }

        return "Excel 导出成功！";
    }

    private static class User {
        private String name;
        private int age;
        private String gender;

        public User(String name, int age, String gender) {
            this.name = name;
            this.age = age;
            this.gender = gender;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getAge() {
            return age;
        }

        public void setAge(int age) {
            this.age = age;
        }

        public String getGender() {
            return gender;
        }

        public void setGender(String gender) {
            this.gender = gender;
        }
    }
}

这份代码会在浏览器端提供一个 /export/excel 接口，访问该接口后会在后端生成一个 users.xlsx 文件，其中包含了用户信息列表和一个年龄统计图。