java导出excel思路

1、构建导出的数据模型，

这个模型可以自己画，也可以读取一个自己制作好的模板，根据模板填充数据，然后flush到一个新的excel文件。

1）、自己画

@GetMapping("/exportTemplate")
    public void exportTemplate(HttpServletResponse response) throws IOException {
        String column1Name1 = "时间戳";
        String column1Name2 = "设备名称";
        List headList = new ArrayList<>();
        headList.add(column1Name1);
        headList.add(column1Name2);

        //在内存操作，写到浏览器
        ExcelWriter writer= ExcelUtil.getWriter(true);
 
        // 设置表头的宽度
        writer.setColumnWidth(0, 20);
        writer.addHeaderAlias("timestamp",column1Name1);
        writer.setColumnWidth(1, 15);
        writer.addHeaderAlias("deviceName",column1Name2);
 
        // 默认的，未添加alias的属性也会写出，如果想只写出加了别名的字段，可以调用此方法排除之
        writer.setOnlyAlias(true);
 
        // 表格内容【相比上一节新内容】
        List excelList = new ArrayList<>();
        CollectDataExcelVo vo1 = new CollectDataExcelVo();
        vo1.setDeviceName("A类设备");
        vo1.setTimestamp(DateUtil.format(new Date()));
        excelList.add(vo1);
        CollectDataExcelVo vo2 = new CollectDataExcelVo();
        vo2.setDeviceName("B类设备");
        vo2.setTimestamp(DateUtil.format(new Date()));
        excelList.add(vo2);
 
        writer.writeHeadRow(headList).write(excelList);
        //设置content—type
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset:utf-8");
 
        response.setHeader("Content-Disposition","attachment;filename="+URLEncoder.encode("数据集导入模板","UTF-8")+".xlsx");
        ServletOutputStream outputStream= response.getOutputStream();
 
        //将Writer刷新到OutPut
        writer.flush(outputStream,true);
        outputStream.close();
        writer.close();
    }

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2、读取自定义的模板，如

public static void responseExport(HttpServletResponse response, Workbook workbook, String fileName) throws IOException {
    response.setHeader("Content-Disposition",
            "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8") + ".xlsx");
    response.setContentType("application/force-download");
    response.setContentType("application/vnd.ms-excel;charset=UTF-8");
    response.setHeader("Pragma", "no-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);
    BufferedOutputStream bufferedOutPut = new BufferedOutputStream(response.getOutputStream());
    workbook.write(bufferedOutPut);
    bufferedOutPut.flush();
    bufferedOutPut.close();
}