后端生成excel文件字节流（前端使用blob保存文件）

package util;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.springframework.util.StringUtils;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.lang.reflect.Method;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Excel工具类
 *
 * @Author admin
 * @date 2018/9/26
 */
public class ExcelUtils {

    /**
     * @param request
     * @param response
     * @param fileName    文件名
     * @param projects    对象集合
     * @param columnNames 列名
     * @param keys        map中的key
     * @throws IOException
     */
    public static void exportExcel(HttpServletRequest request, HttpServletResponse response, String fileName, List projects, String[] columnNames, String[] keys) throws IOException {
        //封装对象属性
        List> list = createExcelRecord(projects, keys);
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        try {
            //将转换成的Workbook对象通过流形式下载
            createWorkBook(list, keys, columnNames).write(os);
        } catch (IOException e) {
            e.printStackTrace();
        }
        byte[] content = os.toByteArray();
        InputStream is = new ByteArrayInputStream(content);

        // 设置response参数，可以打开下载页面
        response.reset();
        response.setContentType("application/vnd.ms-excel;charset=utf-8");
        response.setHeader("Content-Disposition", "attachment;filename=" + encodeFileName(fileName, request));
        ServletOutputStream out = response.getOutputStream();
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        try {
            bis = new BufferedInputStream(is);
            bos = new BufferedOutputStream(out);
            byte[] buff = new byte[2048];
            int bytesRead;
            while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
                bos.write(buff, 0, bytesRead);
            }
        } catch (final IOException e) {
            throw e;
        } finally {
            if (bis != null)
                bis.close();
            if (bos != null)
                bos.close();
        }
    }

    /**
     * 封装对象属性
     *
     * @param projects
     * @param keys
     * @return
     */
    private static List> createExcelRecord(List projects, String[] keys) {
        List> listmap = new ArrayList>();
        Map map = new HashMap();
        map.put("sheetName", "sheet");
        listmap.add(map);
        Object project = null;
        for (int j = 0; j < projects.size(); j++) {
            project = projects.get(j);
            Map mapValue = new HashMap();
            for (int i = 0; i < keys.length; i++) {
                mapValue.put(keys[i], getFieldValueByName(keys[i], project));
            }

            listmap.add(mapValue);
        }
        return listmap;
    }

    /**
     * 利用反射  根据属性名获取属性值
     */
    private static Object getFieldValueByName(String fieldName, Object o) {
        try {
            String firstLetter = fieldName.substring(0, 1).toUpperCase();
            String getter = "get" + firstLetter + fieldName.substring(1);
            Method method = o.getClass().getMethod(getter, new Class[]{});
            Object value = method.invoke(o, new Object[]{});
            return value;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 创建excel文档对象
     *
     * @param keys        list中map的key数组集合
     * @param columnNames excel的列名
     */
    private static Workbook createWorkBook(List> list, String[] keys, String columnNames[]) {
        // 创建excel工作簿
        Workbook wb = new HSSFWorkbook();

        // 创建第一个sheet（页），并命名
        Sheet sheet = wb.createSheet(list.get(0).get("sheetName").toString());

        // 手动设置列宽。第一个参数表示要为第几列设；，第二个参数表示列的宽度，n为列高的像素数。
        for (int i = 0; i < keys.length; i++) {
            sheet.setColumnWidth((short) i, (short) (35.7 * 150));
        }

        // 创建第一行
        Row row = sheet.createRow((short) 0);

        // 创建两种单元格格式
        CellStyle cs = wb.createCellStyle();
        CellStyle cs2 = wb.createCellStyle();

        // 创建两种字体
        Font f = wb.createFont();
        Font f2 = wb.createFont();

        // 创建第一种字体样式（用于列名）
        f.setFontHeightInPoints((short) 10);
        f.setColor(IndexedColors.BLACK.getIndex());
        f.setBoldweight(Font.BOLDWEIGHT_BOLD);

        // 创建第二种字体样式（用于值）
        f2.setFontHeightInPoints((short) 10);
        f2.setColor(IndexedColors.BLACK.getIndex());

        // 设置第一种单元格的样式（用于列名）
        cs.setFont(f);
        cs.setBorderLeft(CellStyle.BORDER_THIN);
        cs.setBorderRight(CellStyle.BORDER_THIN);
        cs.setBorderTop(CellStyle.BORDER_THIN);
        cs.setBorderBottom(CellStyle.BORDER_THIN);
        cs.setAlignment(CellStyle.ALIGN_CENTER);

        // 设置第二种单元格的样式（用于值）
        cs2.setFont(f2);
        cs2.setBorderLeft(CellStyle.BORDER_THIN);
        cs2.setBorderRight(CellStyle.BORDER_THIN);
        cs2.setBorderTop(CellStyle.BORDER_THIN);
        cs2.setBorderBottom(CellStyle.BORDER_THIN);
        cs2.setAlignment(CellStyle.ALIGN_CENTER);

        //设置列名
        for (int i = 0; i < columnNames.length; i++) {
            Cell cell = row.createCell(i);
            cell.setCellValue(columnNames[i]);
            cell.setCellStyle(cs);
        }

        //设置每行每列的值
        for (short i = 1; i < list.size(); i++) {
            // Row 行,Cell 方格 , Row 和 Cell 都是从0开始计数的
            // 创建一行，在页sheet上
            Row row1 = sheet.createRow((short) i);

            // 在row行上创建一个方格
            for (short j = 0; j < keys.length; j++) {
                Cell cell = row1.createCell(j);
                cell.setCellValue(list.get(i).get(keys[j]) == null ? " " : list.get(i).get(keys[j]).toString());
                cell.setCellStyle(cs2);
            }
        }
        return wb;
    }

    /**
     * 设置下载文件中文件的名称
     *
     * @param fileName
     * @param request
     * @return
     */
    public static String encodeFileName(String fileName, HttpServletRequest request) {
        /**
         * 获取客户端浏览器和操作系统信息
         * 在IE浏览器中得到的是：User-Agent=Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon; Alexa Toolbar)
         * 在Firefox中得到的是：User-Agent=Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.7.10) Gecko/20050717 Firefox/1.0.6
         */
        String agent = request.getHeader("USER-AGENT");
        try {
            //Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Safari/537.36 Edge/13.10586 -------IE edge
            if ((agent != null) && ((-1 != agent.indexOf("MSIE")) || (-1 != agent.indexOf("like Gecko")))) {
                String newFileName = URLEncoder.encode(fileName, "UTF-8");
                newFileName = StringUtils.replace(newFileName, "+", "%20");
                if (newFileName.length() > 150) {
                    newFileName = new String(fileName.getBytes("UTF-8"), "ISO8859-1");
                    newFileName = StringUtils.replace(newFileName, " ", "%20");
                }
                return newFileName;
            }
//            if ((agent != null) && (-1 != agent.indexOf("Mozilla")))
//                return MimeUtility.encodeText(fileName, "UTF-8", "B");
            return fileName;
        } catch (Exception ex) {
            return fileName;
        }
    }
}

 使用：

        List list = raiseProjectMemberParticipateService.queryMemberParticipateList();
        // 列名
        String columnNames[] = {"会员手机号", "产品编码", "产品份额", "退回份额", "项目名称", "参与产品名称", "参与状态",
                "参与时间","修改时间","修改人"};
        // map中的key
        String keys[] = {"phoneCode", "prodCode", "number", "updateNumber", "projectName", "prodName", "participateStatusDesc",
                "crtDate", "modDate", "modOper"};
        try {
            ExcelUtils.exportExcel(request, response, fileName, list, columnNames, keys);
        } catch (IOException e) {
            logger.error("导出项目参与列表Excel失败!{}", e);
        }

不用返回值，直接以流的形式返回