SpringBoot中的文件下载功能实现教程

// ExcelXlsUtil.java
public static void writeXls(HttpServletResponse response, 
                           String fileName, 
                           String[] headers, 
                           List<List<String>> data) throws IOException {
    // 1. 创建工作簿和工作表
    HSSFWorkbook workbook = new HSSFWorkbook();
    HSSFSheet sheet = workbook.createSheet("Sheet1");
    
    // 2. 创建表头行
    HSSFRow headerRow = sheet.createRow(0);
    for (int i = 0; i < headers.length; i++) {
        headerRow.createCell(i).setCellValue(headers[i]);
    }
    
    // 3. 填充数据行
    for (int i = 0; i < data.size(); i++) {
        HSSFRow row = sheet.createRow(i + 1);
        List<String> rowData = data.get(i);
        for (int j = 0; j < rowData.size(); j++) {
            row.createCell(j).setCellValue(rowData.get(j));
        }
    }
    
    // 4. 设置响应头
    response.setContentType("application/vnd.ms-excel");
    response.setCharacterEncoding("utf-8");
    response.setHeader("Content-Disposition", 
        "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8") + ".xls");
    
    // 5. 写入响应流
    try (OutputStream os = response.getOutputStream()) {
        workbook.write(os);
    }
    workbook.close();
}

@GetMapping("/downloadDirect")
public void downloadDirect(HttpServletResponse response) throws IOException {
    // 1. 准备数据
    String[] headers = {"ID", "姓名", "手机号"};
    List<List<String>> data = Arrays.asList(
        Arrays.asList("1", "张三", "13800138000"),
        Arrays.asList("2", "李四", "13900139000")
    );
    
    // 2. 调用下载工具
    ExcelXlsUtil.writeXls(response, "用户列表", headers, data);
}

    @GetMapping("/exportExcel")
    public Result exportAndSaveExcel(PersonSelectForm personSelectForm) throws IOException {
        // 1. 获取数据
        List<PersonForm> resultList = getresList(personSelectForm);

        // 2. 创建工作簿和工作表
        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet("Sheet1");

        // 3. 写入数据
        int rowIndex = 0;

        // 3.1 写标题（合并单元格）
        HSSFRow titleRow = sheet.createRow(rowIndex++);
        titleRow.createCell(0).setCellValue("住户信息明细表");
        // 合并第一行单元格（0行，合并0~8列）
        sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, 8));

        // 3.2 写表头
        HSSFRow headerRow = sheet.createRow(rowIndex++);
        String[] headers = new String[] {
                "ID", "小区名称", "所属楼栋", "房号", "姓名", "性别", "手机号码", "居住性质", "备注"
        };
        for (int i = 0; i < headers.length; i++) {
            headerRow.createCell(i).setCellValue(headers[i]);
        }

        // 3.3 写数据行
        for (PersonForm person : resultList) {
            HSSFRow row = sheet.createRow(rowIndex++);
            row.createCell(0).setCellValue(person.getPersonId() != null ? person.getPersonId().toString() : "");
            row.createCell(1).setCellValue(person.getCommunityName() != null ? person.getCommunityName() : "");
            row.createCell(2).setCellValue(person.getTermName() != null ? person.getTermName() : "");
            row.createCell(3).setCellValue(person.getHouseNo() != null ? person.getHouseNo() : "");
            row.createCell(4).setCellValue(person.getUserName() != null ? person.getUserName() : "");
            row.createCell(5).setCellValue(person.getSex() != null ? person.getSex() : "");
            row.createCell(6).setCellValue(person.getMobile() != null ? person.getMobile() : "");
            row.createCell(7).setCellValue(person.getPersonType() != null ? person.getPersonType() : "");
            row.createCell(8).setCellValue(person.getRemark() != null ? person.getRemark() : "");
        }

        // 4. 生成文件名
        String fileName = "住户信息_" + System.currentTimeMillis() + ".xls";

        // 5. 定义保存路径，确保路径最后有分隔符
        String excelpath = "D:\\javacode\\community_vue\\community\\FileXls\\";
        File dir = new File(excelpath);
        if (!dir.exists()) {
            dir.mkdirs();
        }

        // 6. 完整文件路径
        File file = new File(excelpath + fileName);

        // 7. 写入本地文件
        try (FileOutputStream fos = new FileOutputStream(file)) {
            workbook.write(fos);
        } finally {
            workbook.close();
        }

        // 8. 返回相对路径或文件名（前端用下载接口访问，不建议直接返回本地绝对路径）
        String relativePath = fileName; // 你可以根据自己配置修改

        // 如果你没有配置静态资源映射，需要写一个下载接口来读取 D:\javacode\community_vue\community\FileXls 文件夹里的文件

        return Result.ok().put("data", relativePath);
    }