1.引入poi依赖

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.17</version>
</dependency>

2.创建Excel导出工具类

public class ExcelUtils {

    /**
     * Excel表格导出
     *
     * @param response    HttpServletResponse对象
     * @param excelData   Excel表格的数据，封装为List<List<String>>
     * @param sheetName   sheet的名字
     * @param fileName    导出Excel的文件名
     * @param columnWidth Excel表格的宽度
     * @throws IOException 抛IO异常
     */
    public static void exportExcel(HttpServletResponse response,
                                   List<List<String>> excelData,
                                   String sheetName,
                                   String fileName,
                                   int columnWidth) throws IOException {
        //声明一个工作簿
        HSSFWorkbook workbook = new HSSFWorkbook();
        //生成一个表格，设置表格名称
        HSSFSheet sheet = workbook.createSheet(sheetName);
        //设置表格列宽度
        sheet.setDefaultColumnWidth(columnWidth);

        //写入List<List<String>>中的数据
        int rowIndex = 0;
        for (List<String> data : excelData) {
            //创建一个row行，然后自增1
            HSSFRow row = sheet.createRow(rowIndex++);
            //遍历添加本行数据
            for (int i = 0; i < data.size(); i++) {
                //创建一个单元格
                HSSFCell cell = row.createCell(i);
                //创建一个内容对象
                HSSFRichTextString text = new HSSFRichTextString(data.get(i));
                //将内容对象的文字内容写入到单元格中
                cell.setCellValue(text);
            }
        }

        //准备将Excel的输出流通过response输出到页面下载
        //八进制输出流
        response.setContentType("application/octet-stream");
        //设置导出Excel的名称
        response.setHeader("Content-disposition", "attachment;filename=" + fileName);
        //刷新缓冲
        response.flushBuffer();
        //workbook将Excel写入到response的输出流中，供页面下载该Excel文件
        workbook.write(response.getOutputStream());
        //关闭workbook
        workbook.close();
    }
}

3.创建service

@Service
public class ExcelService {

    public List<List<String>> excelTest() {
        List<List<String>> excelData = new ArrayList<>();

        //设置表头
        List<String> head = new ArrayList<>();
        head.add("列1");
        head.add("列2");
        head.add("列3");
        excelData.add(head);

        //设置数据
        List<String> data1 = new ArrayList<>();
        data1.add("A1");
        data1.add("A2");
        data1.add("A3");
        excelData.add(data1);
        List<String> data2 = new ArrayList<>();
        data2.add("B1");
        data2.add("B2");
        data2.add("B3");
        excelData.add(data2);
        
        return excelData;
    }
}

4.创建controller

@RestController
@RequestMapping("/demo/excel")
public class ExcelController {
    @Autowired
    private ExcelService excelService;

    /**
     * Excel表格导出接口
     * http://localhost:8998/demo/excel/export
     *
     * @param response response对象
     * @throws IOException 抛IO异常
     */
    @GetMapping("/export")
    public void excelDownload(HttpServletResponse response) throws IOException {
        List<List<String>> excelData = excelService.excelTest();
        String sheetName = "测试";
        String fileName = "test.xls";
        ExcelUtils.exportExcel(response, excelData, sheetName, fileName, 15);
    }
}

5.启动项目，浏览器中访问 http://localhost:8998/demo/excel/export ，得到文件如下：

 

 

项目已上传github：https://github.com/HeliosFz/SpringBoot-Excel