注意headArr 和fieldArr 数量和顺序都需保持一致即可

    //不创建对象的导出
    public void write(OutputStream out, String[] headArr, String sheetName, List<Map> dataList, String[] fieldArr) throws IOException {
        EasyExcel.write(out).head(head(headArr)).sheet(sheetName).doWrite(dataList(dataList, fieldArr));
    }

//设置表头
    private List<List<String>> head(String[] headMap) {
        List<List<String>> list = new ArrayList<List<String>>();

        for (String head : headMap) {
            List<String> headList = new ArrayList<String>();
            headList.add(head);
            list.add(headList);
        }
        return list;
    }

    //设置导出的数据内容
    private List<List<Object>> dataList(List<Map> dataList, String[] dataStrMap) {
        List<List<Object>> list = new ArrayList<>();
        dataList.stream().forEach(map->{
            List<Object> data = new ArrayList<Object>();
            for (int i = 0; i < dataStrMap.length; i++) {
                data.add(getString(map.get(dataStrMap[i])));
            }
            list.add(data);
        });
        return list;
    }

使用模板导出List<Map>数据

//模板文件 
File fileTemp = new File("D:/template.xlsx");
File targetFile = new File("D:/test.xlsx");
//模板文件不能和目标导出文件是一个文件，使用模板文件其实是追加内容写，可能需提前处理一下模板文件，将表头下得行删除掉，不然数据可能不是从你想要得行数开始写入得
ExcelWriterSheetBuilder sheetBuilder = EasyExcel.write().withTemplate(fileTemp).file(targetFile).head(head(headArr)).sheet(sheetName);
            sheetBuilder.needHead(false).doWrite(dataList(dataList, fieldArr));
            out.flush();
            out.close();

删除excel指定行以下所有行

//从 dataRow行开始，删除这一行下面所有行，包括dataRow行
private void delXlsxByRowNum(File fileTemp, Integer dataRow,File targetFile) {
     FileUtils.copyFile(fileTemp, targetFile);
        XSSFWorkbook  wb = null;
        FileOutputStream fileOutputStream=null;
        try {
            fileOutputStream = new FileOutputStream(targetFile);
            wb = new XSSFWorkbook(new FileInputStream(fileTemp));
            XSSFSheet sheet = wb.getSheetAt(0);
            if(dataRow<sheet.getLastRowNum()){
                for (int i = dataRow; i < sheet.getLastRowNum()+1; i++) {
                    Row row = sheet.getRow(i);
                    int lastRowNum = sheet.getLastRowNum();
                    if (i >= 0 && i < lastRowNum) {
                        sheet.shiftRows(i + 1, lastRowNum, -1);// 将行号为i+1一直到行号为lastRowNum的单元格全部上移一行，以便删除i行
                    }
                    if (i == lastRowNum) {
                        if (row != null) {
                            sheet.removeRow(row);
                        }
                    }
                    i--;
                }
            }
            wb.write(fileOutputStream);
            fileOutputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(wb!=null){
                try {
                    wb.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(fileOutputStream!=null){
                try {
                    fileOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }