Java使用POI导出Excel .xlsx提示文件格式或文件扩展名有误

1.前端如果用xlsx格式接收表格  后台用XSSFWorkbook workbook = new XSSFWorkbook();创建工作薄

 response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
 response.addHeader("Content-Disposition", "attachment;filename=fileName" + ".xlsx");

2.前端如果用xls格式接收表格  后台 用HSSFWorkbook workbook = new HSSFWorkbook();创建工作薄

response.setContentType("application/vnd.ms-excel");
response.addHeader("Content-Disposition", "attachment;filename=fileName"+".xls");

步骤：

$("#exportBtn").click(function() {
        var start_tjsj = $('#start_tjsj').val();
        var end_tjsj = $('#end_tjsj').val();

        var searchCondition = $('#searchCondition option:selected').val();
        window.parent.location.href = "../QtAjtj/exportQtAgtj?start_tjsj=" + start_tjsj+ "&end_tjsj=" + end_tjsj;

    });

 public void exportAytj(List<Aytj> aytjlist,String titleName) {
        ServletOutputStream out=null;

        //向指定的Excel中写入数据
        //设置最大数据行数
        SXSSFWorkbook wb = new SXSSFWorkbook(5000);

        try {

            Map<String,List<CellModel>> map = new HashMap<String,List<CellModel>>();
            // 设置数据
            List<CellModel> firstRow = new ArrayList<CellModel>();
            CellModel cellModel1 = new CellModel();
            //总占用2行
            Integer cellRow = 2;
            cellModel1.setCellName("案由");
            cellModel1.setStartRow(1);
            cellModel1.setEndRow(2);
            cellModel1.setStartColumn(0);
            cellModel1.setEndColumn(0);

            CellModel cellModel2 = new CellModel();
            cellModel2.setCellName("侦监");
            cellModel2.setStartRow(1);
            cellModel2.setEndRow(1);
            cellModel2.setStartColumn(1);
            cellModel2.setEndColumn(4);

            CellModel cellModel3 = new CellModel();
            cellModel3.setCellName("公诉");
            cellModel3.setStartRow(1);
            cellModel3.setEndRow(1);
            cellModel3.setStartColumn(5);
            cellModel3.setEndColumn(8);

            CellModel cellModel4 = new CellModel();
            cellModel4.setCellName("合计");
            cellModel4.setStartRow(1);
            cellModel4.setEndRow(2);
            cellModel4.setStartColumn(9);
            cellModel4.setEndColumn(9);

            firstRow.add(cellModel1);
            firstRow.add(cellModel2);
            firstRow.add(cellModel3);
            firstRow.add(cellModel4);
            map.put("0", firstRow);

            List<CellModel> secondRow = new ArrayList<CellModel>();
            CellModel cellModel5 = new CellModel();
            cellModel5.setCellName("收案");
            cellModel5.setStartRow(2);
            cellModel5.setEndRow(2);
            cellModel5.setStartColumn(1);
            cellModel5.setEndColumn(1);

            CellModel cellModel6 = new CellModel();
            cellModel6.setCellName("分案");
            cellModel6.setStartRow(2);
            cellModel6.setEndRow(2);
            cellModel6.setStartColumn(2);
            cellModel6.setEndColumn(2);

            CellModel cellModel7 = new CellModel();
            cellModel7.setCellName("在办");
            cellModel7.setStartRow(2);
            cellModel7.setEndRow(2);
            cellModel7.setStartColumn(3);
            cellModel7.setEndColumn(3);

            CellModel cellModel8 = new CellModel();
            cellModel8.setCellName("结案");
            cellModel8.setStartRow(2);
            cellModel8.setEndRow(2);
            cellModel8.setStartColumn(4);
            cellModel8.setEndColumn(4);

            CellModel cellModel9 = new CellModel();
            cellModel9.setCellName("收案");
            cellModel9.setStartRow(2);
            cellModel9.setEndRow(2);
            cellModel9.setStartColumn(5);
            cellModel9.setEndColumn(5);

            CellModel cellModel10 = new CellModel();
            cellModel10.setCellName("分案");
            cellModel10.setStartRow(2);
            cellModel10.setEndRow(2);
            cellModel10.setStartColumn(6);
            cellModel10.setEndColumn(6);

            CellModel cellModel11 = new CellModel();
            cellModel11.setCellName("在办");
            cellModel11.setStartRow(2);
            cellModel11.setEndRow(2);
            cellModel11.setStartColumn(7);
            cellModel11.setEndColumn(7);

            CellModel cellModel12 = new CellModel();
            cellModel12.setCellName("结案");
            cellModel12.setStartRow(2);
            cellModel12.setEndRow(2);
            cellModel12.setStartColumn(8);
            cellModel12.setEndColumn(8);

            secondRow.add(cellModel5);
            secondRow.add(cellModel6);
            secondRow.add(cellModel7);
            secondRow.add(cellModel8);
            secondRow.add(cellModel9);
            secondRow.add(cellModel10);
            secondRow.add(cellModel11);
            secondRow.add(cellModel12);
            map.put("1", secondRow);


            List<LinkedHashMap> exportData = new ArrayList<LinkedHashMap>();
            if(aytjlist != null && !aytjlist.isEmpty()) {
                for (int i = 0; i < aytjlist.size(); i++) {

                    Aytj aytj = aytjlist.get(i);
                    LinkedHashMap<String, Object> rowPut = new LinkedHashMap<String, Object>();
                    rowPut.put("1", aytj.getAy());
                    rowPut.put("2", aytj.getZjsacount());
                    rowPut.put("3", aytj.getZjfacount());
                    rowPut.put("4", aytj.getZjzbcount());
                    rowPut.put("5", aytj.getZjbjcount());

                    rowPut.put("6", aytj.getGssacount());
                    rowPut.put("7", aytj.getGsfacount());
                    rowPut.put("8", aytj.getGszbcount());
                    rowPut.put("9", aytj.getGsbjcount());
                    rowPut.put("10", aytj.getAjcount());
                    exportData.add(rowPut);
                }
            }
            Integer columnSize = 10;


            wb = ExcelUtils.createCSVUtil("案由统计",titleName,wb, map, cellRow,columnSize, exportData,"aytj");

            SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
            String fileName = "案由统计_" +format.format(new Date()) ;
            //解决IE文件名乱码
            String userAgent = request.getHeader("user-agent");
            if (userAgent != null && userAgent.indexOf("Firefox") >= 0 || userAgent.indexOf("Chrome") >= 0
                    || userAgent.indexOf("Safari") >= 0) {
                fileName= new String(fileName.getBytes("utf-8"),"ISO8859_1");
            } else {
                fileName= URLEncoder.encode(fileName,"UTF8"); //其他浏览器

            }
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.addHeader("Content-Disposition", "attachment;filename=" +fileName+ ".xlsx");
           /* response.reset();
            //设置response的Header
            response.addHeader("Content-Disposition", "attachment;filename="+ fileName + ".xls");
            //out = new BufferedOutputStream(response.getOutputStream());*/
            out=response.getOutputStream();
         //   response.setContentType("application/vnd.ms-excel;charset=utf-8");

            //创建一个输出流
            ServletOutputStream outputStream = response.getOutputStream();
            //写入数据
            wb.write(outputStream);

            // 关闭
            outputStream.close();
            wb.close();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {}
            }
            if (wb != null) {
                wb.dispose();//删除保存的临时文件。
            }
        }

    }

poi使用SXSSFWorkbook生成表格（用于生成复杂表头）

package com.netmarch.ajgl.common.utils.exportExcel;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.ss.util.RegionUtil;
import org.apache.poi.xssf.streaming.SXSSFCell;
import org.apache.poi.xssf.streaming.SXSSFRow;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFCell;

import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * @Author: songyaru
 * @Date: 2020/5/14 8:58
 * @Version 1.0
 */
public class ExcelUtils {

    /**
     * 生成表格（用于生成复杂表头）
     *
     * @param sheetName   sheet名称
     * @param wb          表对象
     * @param cellListMap 表头数据 {key=cellRowNum-1}
     * @param cellRowNum  表头总占用行数
     * @param exportData  行数据
     * @return
     * @throws Exception
     */
    @SuppressWarnings({"rawtypes", "unchecked"})
    public static SXSSFWorkbook createCSVUtil(String sheetName,String titleName, SXSSFWorkbook wb, Map<String, List<CellModel>> cellListMap,
                                              Integer cellRowNum,Integer columnSize, List<LinkedHashMap> exportData,String tjType) throws Exception {
        //设置表格名称
        SXSSFSheet sheet = (SXSSFSheet) wb.createSheet(sheetName);
        sheet.trackAllColumnsForAutoSizing();
        sheet.autoSizeColumn(1, true);

        //标题字体
        Font titleFont = wb.createFont();
        titleFont.setFontName("宋体");
        titleFont.setFontHeightInPoints((short) 18);
       // headerFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);//粗体显示
        titleFont.setBold(true);//粗体显示
        titleFont.setColor(IndexedColors.BLACK.getIndex());

        //表头
        Font headerFont = wb.createFont();
        headerFont.setFontName("宋体");
        headerFont.setFontHeightInPoints((short) 14);
        // headerFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);//粗体显示
        headerFont.setBold(true);//粗体显示
        headerFont.setColor(IndexedColors.BLACK.getIndex());

        //正文字体
        Font contextFont = wb.createFont();
        contextFont.setFontName("宋体");
        contextFont.setFontHeightInPoints((short) 12);

        contextFont.setColor(IndexedColors.BLACK.getIndex());

        //标题样式，左右上下居中
        CellStyle titleStyle = wb.createCellStyle();
        titleStyle.setFont(titleFont);
        titleStyle.setAlignment(HorizontalAlignment.CENTER);// 左右居中
        titleStyle.setVerticalAlignment(VerticalAlignment.CENTER);// 上下居中
        titleStyle.setLocked(true);
        titleStyle.setBorderBottom(BorderStyle.THIN); //下边框

        //表头样式，左右上下居中
        CellStyle headerStyle = wb.createCellStyle();
        headerStyle.setFont(headerFont);
        headerStyle.setAlignment(HorizontalAlignment.CENTER);// 左右居中
        headerStyle.setVerticalAlignment(VerticalAlignment.CENTER);// 上下居中
        headerStyle.setLocked(true);
        headerStyle.setWrapText(false);// 自动换行
        headerStyle.setBorderBottom(BorderStyle.THIN); //下边框
        headerStyle.setBorderLeft(BorderStyle.THIN);//左边框
        headerStyle.setBorderTop(BorderStyle.THIN);//上边框
        headerStyle.setBorderRight(BorderStyle.THIN);//右边框

        //单元格样式，左右上下居中 边框
        CellStyle commonStyle = wb.createCellStyle();
        commonStyle.setFont(contextFont);
        commonStyle.setAlignment(HorizontalAlignment.CENTER);// 左右居中
        commonStyle.setVerticalAlignment(VerticalAlignment.CENTER);// 上下居中
        commonStyle.setWrapText(false);// 自动换行
        commonStyle.setBorderBottom(BorderStyle.THIN); //下边框
        commonStyle.setBorderLeft(BorderStyle.THIN);//左边框
        commonStyle.setBorderTop(BorderStyle.THIN);//上边框
        commonStyle.setBorderRight(BorderStyle.THIN);//右边框

        //单元格样式，竖向 边框
        CellStyle verticalStyle = wb.createCellStyle();
        verticalStyle.setFont(contextFont);
        verticalStyle.setAlignment(HorizontalAlignment.CENTER);// 左右居中
        verticalStyle.setVerticalAlignment(VerticalAlignment.CENTER);// 上下居中
        verticalStyle.setRotation((short) 255);//竖向
        verticalStyle.setLocked(true);
        verticalStyle.setWrapText(false);// 自动换行
        verticalStyle.setBorderBottom(BorderStyle.THIN); //下边框
        verticalStyle.setBorderLeft(BorderStyle.THIN);//左边框
        verticalStyle.setBorderTop(BorderStyle.THIN);//上边框
        verticalStyle.setBorderRight(BorderStyle.THIN);//右边框


        // 产生表格标题行
        Row titleRow = sheet.createRow(0);
        Cell cellTiltle = titleRow.createCell(0);
        sheet.setDefaultColumnWidth(15);
        CellRangeAddress titelCellRange=new CellRangeAddress(0, 0, 0, (columnSize - 1));
        sheet.addMergedRegion(titelCellRange);
        RegionUtil.setBorderBottom(BorderStyle.THIN, titelCellRange, sheet);//设置合并单元格的边框
        /*设置行高*/
        titleRow.setHeight((short)800);

        cellTiltle.setCellStyle(titleStyle);
        cellTiltle.setCellValue(titleName);


        for (int t = 0; t < cellRowNum; t++) {
            SXSSFRow row = (SXSSFRow) sheet.createRow(t+1);
            List<CellModel> cellNameList = cellListMap.get(String.valueOf(t));

            for (CellModel cellModel : cellNameList) {
                if (cellModel.getStartRow() == cellModel.getEndRow() && cellModel.getStartColumn() == cellModel.getEndColumn()) {
                    //【开始行和结束行在同一行】   和   【开始列和结束列在同一列】同时出现的话，那就没有合并单元格的意义了。
                } else {
                    CellRangeAddress cellRangeAddress=new CellRangeAddress(cellModel.getStartRow(),
                            cellModel.getEndRow(), cellModel.getStartColumn(), cellModel.getEndColumn());
                    sheet.addMergedRegion(cellRangeAddress);
                }
            }

            for (int i = 0; i < cellNameList.size(); i++) {
                CellModel cellModel = cellNameList.get(i);
                // 遍历插入表头
                SXSSFCell cell = (SXSSFCell) row.createCell(cellModel.getStartColumn());
                cell.setCellValue(cellModel.getCellName());
                cell.setCellStyle(headerStyle);
            }
        }
        for (LinkedHashMap hashMap : exportData) {
            SXSSFRow rowValue = (SXSSFRow) sheet.createRow(cellRowNum+1);
            Iterator<Map.Entry> iteratorRow = hashMap.entrySet().iterator();
            while (iteratorRow.hasNext()) {
                Map.Entry entryRow = iteratorRow.next();
                Integer key = Integer.valueOf(entryRow.getKey().toString());
                String value = "";
                if (entryRow.getValue() != null) {
                    value = entryRow.getValue().toString();
                } else {
                    value = "";
                }
                SXSSFCell cellValue = (SXSSFCell) rowValue.createCell(key - 1);
                cellValue.setCellValue(value);
                cellValue.setCellStyle(commonStyle);
            }
            cellRowNum++;
        }

     
            /*设置行宽*/
            int columnWidth[] = {8000, 3000, 3000, 3000, 3000, 3000, 3000, 3000, 3000, 3000};
            for (int i = 0; i < columnSize; i++) {
                sheet.setColumnWidth(i, columnWidth[i]);
            }
            //合并单元框边框有问题，需要在全部单元格合并之后调整边框,否则会覆盖的
            CellRangeAddress cellRangeAddress = new CellRangeAddress(1, 2, 9, 9);
            RegionUtil.setBorderRight(BorderStyle.THIN, cellRangeAddress, sheet);//设置合并单元格的右边框
        


       /*
        // 设置为根据内容自动调整列宽  必须在单元格设值以后进行
        for (int k = 0; k < exportData .size(); k++) {
            sheet.autoSizeColumn(k);
        }
        // 处理中文不能自动调整列宽的问题
        setSizeColumn(sheet, exportData.size());*/


        return wb;
    }

    //poi设置自适应列宽
    private static void setSizeColumn(SXSSFSheet sheet, int size) {
        for (int columnNum = 0; columnNum < size; columnNum++) {
            int columnWidth = sheet.getColumnWidth(columnNum) / 256;
            for (int rowNum = 0; rowNum < sheet.getLastRowNum(); rowNum++) {
                SXSSFRow currentRow;
                //当前行未被使用过
                if (sheet.getRow(rowNum) == null) {
                    currentRow = sheet.createRow(rowNum);
                } else {
                    currentRow = sheet.getRow(rowNum);
                }

                if (currentRow.getCell(columnNum) != null) {
                    SXSSFCell currentCell = currentRow.getCell(columnNum);
                    if (currentCell.getCellType() == XSSFCell.CELL_TYPE_STRING) {
                        int length = currentCell.getStringCellValue().getBytes().length;
                        if (columnWidth < length) {
                            columnWidth = length;
                        }
                    }
                }
            }
            sheet.setColumnWidth(columnNum, columnWidth * 256);
        }
    }

}

 效果：