导出前端响应输出流

1、常规情况下前端请求后端，后端直接写入表格导出输入流即可
后端实现类(使用EasyExcel实现下载功能)：

@Override
    public void exportExcel(HttpServletResponse response) {
        String realPath = "D://home/";
        File folder = new File(realPath);
        if (!folder.isDirectory()) {
            folder.mkdirs();
        }
        // 导出文件名称
        String fileName = realPath + System.currentTimeMillis() + "明细表.xlsx";
        List<ProjectItemDTO> list = new ArrayList<>();
        ProjectItemDTO projectItemDTO = new ProjectItemDTO();
        projectItemDTO.setNumber("1");
        projectItemDTO.setName("项目名称1");
        projectItemDTO.setResponsibleDepartment("处室1");
        projectItemDTO.setManagers("测试1");
        projectItemDTO.setMembers("测试2");
        projectItemDTO.setLevel("一般");
        projectItemDTO.setBudgetAmount("450");
        projectItemDTO.setPaidThisYear("360");
        projectItemDTO.setItemNumber("230003188001074");
        projectItemDTO.setBudgetType("新增预算");
        list.add(projectItemDTO);
        // 设置表格样式 加边框、设置自动换行
        WriteCellStyle contentWriteCellStyle = new WriteCellStyle();
        contentWriteCellStyle.setBorderLeft(BorderStyle.THIN);
        contentWriteCellStyle.setBorderTop(BorderStyle.THIN);
        contentWriteCellStyle.setBorderRight(BorderStyle.THIN);
        contentWriteCellStyle.setBorderBottom(BorderStyle.THIN);
        contentWriteCellStyle.setWrapped(true);
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        headWriteCellStyle.setFillForegroundColor(IndexedColors.WHITE.index);
        EasyExcel.write(fileName, ProjectItemDTO.class).registerWriteHandler(
                new HorizontalCellStyleStrategy(headWriteCellStyle, contentWriteCellStyle)).sheet("数据").doWrite(
                data());
    }

data() 获取导出数据信息

2、后端导出，前端响应输出流
vue前端代码
导出触发的事件方法

// 点击导出
    clickToExport() {
      exportExcel().then(res=>{
        const fileName="计划表.xlsx"
        const blob = new Blob([res],{
          type: 'application/vnd.ms-excel'
        })
        const reader = new FileReader()
        reader.readAsDataURL(blob)
        reader.onload = function () {
          const a = document.createElement('a')
          a.download = fileName
          a.href = URL.createObjectURL(blob)
          document.body.appendChild(a)
          a.click()
          URL.revokeObjectURL(a.href)
          document.body.removeChild(a)
        }
      })
    },

路由配置

export function exportExcel() {
  return request({
    url: '/pc/exportExcel',
    method: 'post',
    responseType: 'blob'
  })
}

后端代码
添加导入导出工具类文件

导入导出工具类.png
后端实现类：

@Override
    public void exportExcel(){
        // 获取输出流
        HttpServletResponse response = RequestContextUtil.getResponse();
        // int year = LocalDateTime.now().getYear();
        List<List<Object>> sheet = new ArrayList<>();
        List<Object> sheetHead = new ArrayList<>();
        // sheetHead.add("序号");
        sheetHead.add("项目名称");
        sheetHead.add("主责部门");
        sheetHead.add("项目经理");
        sheetHead.add("项目成员");
        sheetHead.add("项目分级");
        sheetHead.add("预算金额(万元)");
        sheetHead.add("今年支付");
        sheetHead.add("事项编号");
        sheetHead.add("预算部门");
        sheetHead.add("预算名称");
        sheetHead.add("预算类型");
        sheet.add(sheetHead);
        ArrayList<ProjectItemDTO> exportList = new ArrayList<>();
        List<ProjectItemDTO> projectItemList = data();
        for(ProjectItemDTO projectItemDTO:projectItemList){
            exportList.add(projectItemDTO);
        }
        if(exportList.size()>0){
            int i = 0;
            for(ProjectItemDTO projectItemDTO:exportList){
                i += 1;
                List<Object> sheetrow = new ArrayList<>();
                // sheetrow.add(i);
                String number = StringUtils.isNotEmpty(projectItemDTO.getNumber())?projectItemDTO.getNumber():" ";
                String name = StringUtils.isNotEmpty(projectItemDTO.getName())?projectItemDTO.getName():" ";
                sheetrow.add(number + name);
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getResponsibleDepartment())?projectItemDTO.getResponsibleDepartment():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getManagers())?projectItemDTO.getManagers():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getMembers())?projectItemDTO.getMembers():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getLevel())?projectItemDTO.getLevel():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getBudgetAmount())?projectItemDTO.getBudgetAmount():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getPaidThisYear())?projectItemDTO.getPaidThisYear():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getItemNumber())?projectItemDTO.getItemNumber():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getBudgetDepartment())?projectItemDTO.getBudgetDepartment():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getBudgetName())?projectItemDTO.getBudgetName():" ");
                sheetrow.add(StringUtils.isNotEmpty(projectItemDTO.getBudgetType())?projectItemDTO.getBudgetType():" ");
                sheet.add(sheetrow);
            }
        }
        // 导出执行
        ExcelUtils.export(response, "计划明细表", sheet);
    }

工具类代码及更多导入导出功能可参考该博主的文章：https://zyqok.blog.csdn.net/article/details/121994504