java导出功能后台代码

看代码之前先说一下此导出使用的开发框架，避免某些小可看了半天发现不能用
页面使用的是easyUI JSP
后台使用springboot
前台页面JS代码

function doExcel() {
           let frozenColumns = $('#dg').datagrid('options').frozenColumns;
            let columns = $('#dg').datagrid('options').columns;
            let fieldAndTitle = [];
            if (frozenColumns.length > 0 && columns.length > 0) {
                for (let i = 0; i < columns.length; i++) {
                    for (let j = 0; j < frozenColumns.length; j++) {
                        if (i === j) {
                            fieldAndTitle.push(frozenColumns[j].concat(columns[i]));
                        }
                        if (i > j) {
                            fieldAndTitle.push(columns[i]);
                        }
                        break;
                    }
                }
            }
            if(columns.length == 0 && frozenColumns.length > 0){
                fieldAndTitle = frozenColumns;
            }
            if(frozenColumns.length == 0 && columns.length > 0){
                fieldAndTitle = columns;
            }
        }

后台一个公用的方法，需要在接口里面调取这个方法，并把相关参数写上去就OK了

@RequestMapping(value = "/export")
    public ResponseStatus download(HttpServletResponse response,MapBean mapBean){
        ActionResult ar = ActionResult.New();

        Map<String,Object> dataMap = paymentReportService.businessOperationList(mapBean,ar);
        List<Map<String, Object>> dataList = (List<Map<String, Object>>) dataMap.get("rows");

        Workbook workbook = getWorkBook(mapBean.getString("jspTitle"),dataList,mapBean.getString("fieldAndTitle"));

        try {
            String fileName =new String(mapBean.getString("jspTitle").toString().getBytes(), "iso-8859-1");
            response.setCharacterEncoding("UTF-8");
            response.setContentType("application/vnd.ms-excel;charset=utf8");
            response.addHeader("Content-Disposition", "inline;filename=" + String.format("%s.xlsx",fileName));
            ServletOutputStream outputStream = response.getOutputStream();
            workbook.write(outputStream);
            outputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return ar.toResponseStatus();
    }

    /**
     * 导出共用方法
     * @param sheetName 文件名
     * @param dataList  数据
     * @param fieldAndTitle  表头的列的json串
     * @return
     */
    private Workbook getWorkBook(String sheetName, List<Map<String, Object>> dataList,String fieldAndTitle){

        Workbook workbook = new SXSSFWorkbook(100);
        Sheet sheet = workbook.createSheet(sheetName);

        //居中样式
        CellStyle centerStyle = workbook.createCellStyle();
        centerStyle.setAlignment(HorizontalAlignment.CENTER);
        centerStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        //右对齐样式
        CellStyle rightStyle = workbook.createCellStyle();
        rightStyle.setAlignment(HorizontalAlignment.CENTER);
        rightStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        //日期样式
        CellStyle dateStyle = workbook.createCellStyle();
        dateStyle.setAlignment(HorizontalAlignment.CENTER);
        dateStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        DataFormat format = workbook.createDataFormat();
        dateStyle.setDataFormat(format.getFormat("yyyy-MM-dd"));

        Row row = null;
        Cell cell = null;
        int rowIndex = 0;
        int colIndex = 0;
        int rowSpan;
        int colSpan;
        Map<Integer, String> indexMapper = New.map(); //列顺序索引

        //标题
        List<List<Map<String, Object>>> listList = JsonUtils.parseListListMap(fieldAndTitle);
        List<List<Map<String, Object>>> finalListList = New.list();
        for (List<Map<String, Object>> list : listList) {
            List<Map<String, Object>> ll = New.list();
            for (Map<String, Object> map : list) {
                if (StringUtils.isNullOrEmpty(StringUtils.valueOf(map.get("title"))) || "操作".equals(StringUtils.valueOf(map.get("title")))) {
                    continue;
                }
                for (Map.Entry<String, Object> entry : map.entrySet()) {
                    if ("field".equals(entry.getKey())) {
                        map.put(entry.getKey(), entry.getValue());
                        break;
                    }
                }
                ll.add(map);
            }
            if (list.size() > 0) {
                //需要保证表头的每个列表都要有数据，否则生成excel表格会出错
                finalListList.add(ll);
            }
        }

        if (finalListList.size() > 0) {

            int lastRow, lastCol;
            int column = 0;
            for (Map<String,Object> header : finalListList.get(0)) {
                column += ConvertUtils.toInt(header.get("colspan"),1);
            }
            boolean[][] blnRange = new boolean[finalListList.size()][column]; //二维表格矩陈，false表示可用，默认都可用
            for (int i = 0; i < finalListList.size(); i++) {
                row = sheet.createRow(rowIndex);
                colIndex = 0; //如果是第一行，列索引从0开始
                if (i > 0) {

                    //如果不是第一行，都要计算前面的单元格是否被占用
                    for (int k = 0; k < blnRange[0].length; k++) {
                        if (blnRange[i][k]) {
                            colIndex++; //如果被占用继续向后查
                        } else {
                            break; //否则，退出
                        }
                    }
                }

                for (Map<String, Object> map : finalListList.get(i)) {

                    rowSpan = ConvertUtils.toInt(StringUtils.valueOf(map.get("rowspan")),1);
                    colSpan = ConvertUtils.toInt(StringUtils.valueOf(map.get("colspan")),1);
                    if (rowSpan > 1 || colSpan > 1) {
                        //计算单元格结束的行与列
                        lastRow = rowSpan > 1 ? rowIndex + rowSpan - 1 : rowIndex;
                        lastCol = colSpan > 1 ? colIndex + colSpan - 1 : colIndex;

                        //生成合并的单元格
                        CellRangeAddress cra = new CellRangeAddress(rowIndex, lastRow, colIndex, lastCol);

                        sheet.addMergedRegion(cra);
                        cell = sheet.getRow(rowIndex).createCell(colIndex);
                        //cell = sheet.getRow(rowIndex).getCell(colIndex);
                        cell.setCellStyle(centerStyle);
                        cell.setCellValue(map.get("title").toString());

                        blnRange[rowIndex][colIndex] = true; //只改变当前单元格的状态

                        //改变合并的其他行的相应单元格状态
                        for (int k = rowIndex; k <= lastRow; k++) {
                            for (int j = colIndex; j <= lastCol; j++) {
                                blnRange[k][j] = true;
                            }
                        }
                        if (colSpan <= 1) {
                            indexMapper.put(colIndex, map.get("field").toString()); //添加列索引
                        }
                        colIndex = lastCol + 1;

                    } else {
                        cell = row.createCell(colIndex);
                        cell.setCellStyle(centerStyle);
                        cell.setCellValue(map.get("title").toString());

                        blnRange[rowIndex][colIndex] = true; //设置当前单元格已经被使用
                        indexMapper.put(colIndex, map.get("field").toString()); //添加列索引
                        colIndex++;

                    }
                }
                rowIndex++;
            }
        }

        //数据
        Object dataValue;
        for (Map<String, Object> data : dataList) {
            row = sheet.createRow(rowIndex++);
            for (Map.Entry<Integer, String> entry : indexMapper.entrySet()) {
                cell = row.createCell(entry.getKey());
                dataValue = data.get(entry.getValue());
                if (dataValue == null) {
                    cell.setCellValue("");
                } else if (dataValue instanceof String) {
                    cell.setCellValue(String.valueOf(dataValue));
                } else if (dataValue instanceof Integer ||
                        dataValue instanceof Short ||
                        dataValue instanceof Float ||
                        dataValue instanceof Double ||
                        dataValue instanceof BigDecimal) {
                    //让内容右对齐
                    cell.setCellStyle(rightStyle);
                    cell.setCellValue(Double.valueOf(String.valueOf(dataValue)));
                } else if (dataValue instanceof Long) {
                    //长整形做字符串处理
                    cell.setCellValue(String.valueOf(dataValue));
                } else if (dataValue instanceof Date) {
                    //日期类型
                    cell.setCellStyle(dateStyle);
                    cell.setCellValue((Date) dataValue);
                } else if (dataValue instanceof Boolean) {
                    //日期类型
                    cell.setCellValue((Boolean) dataValue);
                } else {
                    cell.setCellValue(String.valueOf(dataValue));
                }
            }
        }
        return workbook;
    }