poi导出代码思路

java+layui实现导出

思路：先将后台列表上传到本地盘符里面，上传成功之后返回一个本地盘符路径，在根据这个实际路径输出流的形式返回前端，实现下载

1.前端

// 导出
function exportData() {
    $.ajax({
        type : "post",
        url : "/backend/report/stockAnalyse/exportData",
        data : {},
        success : function(result) {
            if (result.status == 0) {
                window.open(result.data)
            }
            if (result.message != null) {
                layer.msg(result.message)
            }
        },
        error : function(XMLHttpRequest, textStatus, errorThrown) {
            layer.msg('{"status":"' + XMLHttpRequest.status + '","readyState":"' + XMLHttpRequest.readyState + '","textStatus":"' + textStatus + '","errorThrown":"' + errorThrown
                + '"}')
        }
    })
};

　2.后端 controller层

    // 导出
    @ResponseBody
    @PostMapping(value = "exportData")
    ResultJson exportData() {
        String excelTitle = "核心报表-库龄分析";
        String path = "/smart/export/stock/excel/"
                + new SimpleDateFormat("yyyyMMddHH-mm-ss").format(new Date());
        String realPath = CommonUtil.createFolderPath(path);
        ResultJson resultJson = new ResultJson();
        resultJson.setStatus(0);
        resultJson.setMessage("导出成功！");
        resultJson.setData(ExcelUtil.exportExcel(excelTitle, realPath, path, CompanyStaffJson.class,
                companyStaffService.findAllForExcel()));
        return resultJson;
    }

　　

3.工具类：遍历本地盘符新建文件夹

public static final String createFolderPath(String folderPath) {
        File file = new File(folderPath);
        if (System.getProperty("os.name").toLowerCase().startsWith("win")) {
            String[] diskNames = {"A:", "B:", "C:", "D:", "E:", "F:", "G:", "H:", "I:", "J:", "K:",
                    "L:", "M:", "N:", "O:", "P:", "Q:", "R:", "S:", "T:", "U:", "V:", "W:", "X:",
                    "Y:", "Z:"};
            for (int i = 0; i < diskNames.length; i++) {
                if (i > 0) {
                    folderPath = folderPath.replace(diskNames[i - 1], diskNames[i]);
                } else {
                    folderPath = diskNames[0] + folderPath;
                }
                file = new File(folderPath);
                if (!file.exists()) {
                    file.mkdirs();
                }
                if (file.exists()) {
                    return folderPath;
                }
            }
            return null;
        } else {
            if (!file.exists()) {
                file.mkdirs();
            }
            if (file.exists()) {
                return folderPath;
            }
            return null;
        }
    }

3. 将查出来的list通过流的形式写入本地文件夹并且返回一个下载路径给前端layui

/**
     * 导出Excel
     * 
     * @param excelTitle Excel标题
     * @param realPath 真实路径
     * @param path 响应路径
     * @param clazz 注解的实体类
     * @param excels 注解的实体类集合
     * @return 完整的响应路径
     */
    public static <T> String exportExcel(String excelTitle, String realPath, String path,
            Class<T> clazz, List<T> excels) {
        try {
            Workbook workbook = ExcelExportUtil
                    .exportExcel(new ExportParams(excelTitle, excelTitle), clazz, excels);
            String filename = excelTitle + "-" + DateUtil.formatDateTimeSerial(null) + ".xls";
            File dirPath = new File(realPath);
            if (!dirPath.exists()) {
                dirPath.mkdirs();
            }
            FileOutputStream outputStream = new FileOutputStream(realPath + "/" + filename);
            workbook.write(outputStream);
            outputStream.close();
            return path + "/" + filename;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

4.前端请求的下载路径被监听到，然后通过方法redirectFile获取本地Excel所保持的路径，并进行下载

@Controller
@RequestMapping(value = "/")
public class IndexController {

    @Autowired
    private UserService userService;
    @Autowired
    private PropertyUtil propertyUtil;

    @RequestMapping(value = "")
    String index() {
        return "redirect:/backend";
    }

    @ResponseBody
    @RequestMapping(value = "registerUser")
    ResultJson registerUser(@Valid SystemUser systemUser, BindingResult result) {
        ResultJson resultJson = new ResultJson();
        if (result.hasErrors()) {
            resultJson.setStatus(1);
            resultJson.setMessage(result.getAllErrors().get(0).getDefaultMessage());
            resultJson.setData(null);
            return resultJson;
        }
        SystemUser findUser = userService.findByEntityName(systemUser.getEntityName());
        if (findUser != null) {
            resultJson.setStatus(1);
            resultJson.setMessage("该用户已存在！");
            resultJson.setData(null);
            return resultJson;
        }
        if (systemUser.getPassword().equals("password")) {
            resultJson.setStatus(1);
            resultJson.setMessage("禁止使用默认密码！");
            resultJson.setData(null);
            return resultJson;
        }
        systemUser.setCreateDate(new Date());
        systemUser.setPassword(StringUtil.md5Encode(systemUser.getPassword()));
        userService.save(systemUser);
        SecurityContextHolder.getContext().setAuthentication(
                new UsernamePasswordAuthenticationToken(systemUser.getEntityName(),
                        systemUser.getPassword()));
        resultJson.setStatus(0);
        resultJson.setMessage("注册成功！");
        resultJson.setData(null);
        return resultJson;
    }

    @ResponseBody
    @RequestMapping(value = "repassUser")
    ResultJson repassUser(String newPass) {
        ResultJson resultJson = new ResultJson();
        if (CommonUtil.isEmpty(newPass)) {
            resultJson.setStatus(1);
            resultJson.setMessage("新密码不能为空！");
            resultJson.setData(null);
            return resultJson;
        }
        SystemUser systemUser = BackendUtil.getLoginUser();
        if (systemUser == null) {
            resultJson.setStatus(1);
            resultJson.setMessage("用户登录失效！");
            resultJson.setData(null);
            return resultJson;
        }
        systemUser.setPassword(StringUtil.md5Encode(newPass));
        systemUser.setUpdateDate(new Date());
        userService.save(systemUser);
        resultJson.setStatus(0);
        resultJson.setMessage("改密成功！");
        resultJson.setData(null);
        return resultJson;
    }

    @RequestMapping(value = {"/smart/**", "/upload/images/**", "/upload/photos/**",
            "/redirectFile/**", "/downloadFile/**", "/export/**", "/ueditor/jsp/upload/**",
            "/upload/attachmentFiles/**"})
    public void redirectFile(HttpServletRequest request, HttpServletResponse response)
            throws IOException {
        String parseName = request.getParameter("parseName");
        String filePath = URLDecoder.decode(request.getRequestURI(), "UTF-8");
        // String folderPath = CommonUtil.checkFolderPath(propertyUtil.getUploadPath() + filePath);
        String folderPath;
        if (filePath.startsWith("/smart")) {
            folderPath = CommonUtil.checkFolderPath(filePath);
        } else {
            folderPath = CommonUtil.checkFolderPath(propertyUtil.getUploadPath() + filePath);
        }
        if (folderPath == null) {
            return;
        }
        File file = new File(folderPath);
        if (!file.exists()) {
            return;
        }
        String fileName = null;
        if (!StringUtil.isEmpty(parseName)) {
            fileName = parseName;
        } else {
            fileName = StringUtil.getFileNameWithSuffix(filePath);
        }
        response.setContentType(request.getServletContext().getMimeType(fileName));
        FileInputStream fileInputStream = null;
        if (filePath.startsWith("/downloadFile") || filePath.startsWith("/export")
                || filePath.startsWith("/upload/attachmentFiles")) {
            if (request.getHeader("User-Agent").toUpperCase().indexOf("MSIE") > 0) {
                response.setHeader("Content-Disposition",
                        "attachment;filename=" + new String(fileName.getBytes("GBK"), "ISO8859-1"));
            } else {
                response.setHeader("Content-Disposition", "attachment;filename="
                        + new String(fileName.getBytes("UTF-8"), "ISO8859-1"));
            }
        }
        fileInputStream = new FileInputStream(file);
        OutputStream outputStream = response.getOutputStream();
        byte[] buffer = new byte[512];
        int count;
        while ((count = fileInputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, count);
        }
        outputStream.flush();
        outputStream.close();
        fileInputStream.close();
    }

    @RequestMapping(value = {"/upload/basicEnclosure/**"})
    public void basicEnclosure(HttpServletRequest request, HttpServletResponse response)
            throws IOException {
        String parsePdf = request.getParameter("parsePdf");
        String parseName = request.getParameter("parseName");
        String filePath = URLDecoder.decode(request.getRequestURI(), "UTF-8");
        String folderPath = CommonUtil.checkFolderPath(propertyUtil.getUploadPath() + filePath);
        if (folderPath == null) {
            return;
        }
        File file = new File(folderPath);
        if (!file.exists()) {
            return;
        }
        String fileName = null;
        if (!StringUtil.isEmpty(parseName)) {
            fileName = parseName;
        } else {
            fileName = StringUtil.getFileNameWithSuffix(filePath);
        }
        response.setContentType(request.getServletContext().getMimeType(fileName));
        FileInputStream fileInputStream = null;
        if (parsePdf != null && (folderPath.endsWith("xls") || folderPath.endsWith("xlsx")
                || folderPath.endsWith("ppt") || folderPath.endsWith("pptx")
                || folderPath.endsWith("doc") || folderPath.endsWith("docx")
                || folderPath.endsWith("pdf"))) {
            response.setContentType("application/pdf");
            response.setHeader("Content-Disposition", "inline;fileName="
                    + new String(fileName.getBytes("GBK"), "ISO8859-1") + ".pdf");
            String output = null;
            if (!folderPath.endsWith("pdf")) {
                output = FilenameUtils.separatorsToSystem(FilenameUtils.getFullPath(folderPath)
                        + FilenameUtils.getBaseName(folderPath) + ".pdf");
            } else {
                output = folderPath;
            }
            File testFile = new File(output);
            if (testFile.exists()) {
                fileInputStream = new FileInputStream(testFile);
            } else {
                fileInputStream = new FileInputStream(PdfUtils.convertToPdf(folderPath, output));
            }
        } else {
            if (request.getHeader("User-Agent").toUpperCase().indexOf("MSIE") > 0) {
                response.setHeader("Content-Disposition",
                        "attachment;filename=" + new String(fileName.getBytes("GBK"), "ISO8859-1"));
            } else {
                response.setHeader("Content-Disposition", "attachment;filename="
                        + new String(fileName.getBytes("UTF-8"), "ISO8859-1"));
            }
            fileInputStream = new FileInputStream(file);
        }
        OutputStream outputStream = response.getOutputStream();
        byte[] buffer = new byte[512];
        int count;
        while ((count = fileInputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, count);
        }
        outputStream.flush();
        outputStream.close();
        fileInputStream.close();
    }

    @RequestMapping(value = {"/downLoad"})
    public void downLoad(HttpServletRequest request, HttpServletResponse response)
            throws IOException {
        String downPath = request.getParameter("file");
        String parseName = request.getParameter("parseName");
        String fileName = null;
        if (!StringUtil.isEmpty(parseName)) {
            fileName = parseName;
        } else {
            fileName = StringUtil.getFileNameWithSuffix(downPath);
        }
        InputStream inputStream = HttpUtil.urlToStream(downPath);
        response.setContentType(request.getServletContext().getMimeType(fileName));
        if (request.getHeader("User-Agent").toUpperCase().indexOf("MSIE") > 0) {
            response.setHeader("Content-Disposition",
                    "attachment;filename=" + new String(fileName.getBytes("GBK"), "ISO8859-1"));
        } else {
            response.setHeader("Content-Disposition",
                    "attachment;filename=" + new String(fileName.getBytes("UTF-8"), "ISO8859-1"));
        }
        OutputStream outputStream = response.getOutputStream();
        byte[] buffer = new byte[512];
        int count;
        while ((count = inputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, count);
        }
        outputStream.flush();
        outputStream.close();
        inputStream.close();
    }

}