poi導出excel表

最近在幫人家做一個查詢的功能，需要用到poi導出excel表格，之前一直也沒有用過，不知道是什麼情況，後來在網上找了些資料看下，也就那麼一回事。希望可以給大家一些思路吧。

首先是創建一個sheet，然後再往裏面添加單元格，如果手動輸出過表格的話，原理其實是差不多的。

來一個完整的方法：

 

/**
     * 導出excel表
     * @throws IOException
     */
    public void showExcel() throws IOException {
        String [] headers= {"設備編碼","設備種類","設備名稱","所屬總站","品牌","規格型號","提供商","設備價格","用途","出廠編號","責任人","生產日期","採購日期","啓用日期","建檔日期","保修日期","報廢期至","備註"};
        String fileName = exportExcels(headers, ServletActionContext.getRequest());
        HttpServletResponse response=ServletActionContext.getResponse();
        response.setContentType("application/vnd.ms-excel; charset=utf-8");
        response.setHeader("Content-Disposition", "attachment;filename="+fileName);
        byte[] buffered = new byte[1024];
        BufferedInputStream input = new BufferedInputStream(new FileInputStream(ServletActionContext.getRequest().getRealPath("/export")+"/"+fileName));
        DataOutputStream output = new DataOutputStream(response.getOutputStream());
        while (input.read(buffered,0,buffered.length) != -1) {
            output.write(buffered,0,buffered.length);
        }
        input.close();
        output.close();
    }

    /**
     * 創建行
     * @param cells
     * @param rowIndex
     * @param demoSheet
     */
    public static void createTableRow(List<String> cells, short rowIndex, HSSFSheet demoSheet) {
        // 創建第rowIndex行
        HSSFRow row = demoSheet.createRow((short) rowIndex);
        for (short i = 0; i < cells.size(); i++) {
            // 創建第i個單元格
            HSSFCell cell = row.createCell((short) i);
            cell.setCellValue(cells.get(i));
        }
    }
    /**
     * 創建sheet
     * @param tableHeader
     * @return
     */
    public  HSSFSheet createExcelSheet(String [] tableHeader,HSSFWorkbook demoWorkBook) {
        List<Device> devices=deviceService.findAllDevices();
        HSSFSheet demoSheet = demoWorkBook.createSheet("devices");
        HSSFHeader header = demoSheet.getHeader();
        header.setCenter("全部設備表");
        HSSFRow headerRow = demoSheet.createRow((short) 0);
        for (int i = 0; i < tableHeader.length; i++) {
            HSSFCell headerCell = headerRow.createCell((short) i);
            headerCell.setCellValue(tableHeader[i]);
        }
        for (int j = 1; j < devices.size(); j++) {
            List<String> list = new ArrayList<String>();
            list.add(devices.get(j).getDev_no()!=null?devices.get(j).getDev_no():"");
            list.add(devices.get(j).getCategory().getCat_name()!=null?devices.get(j).getCategory().getCat_name():"");
            list.add(devices.get(j).getDev_name()!=null?devices.get(j).getDev_name():"");
            list.add(devices.get(j).getDepartment().getDep_name()!=null?devices.get(j).getDepartment().getDep_name():"");
            list.add(devices.get(j).getDev_brand()!=null?devices.get(j).getDev_brand():"");
            list.add(devices.get(j).getDev_spec()!=null?devices.get(j).getDev_spec():"");
            list.add(String.valueOf(devices.get(j).getDev_fac())!=null?String.valueOf(devices.get(j).getDev_fac()):"");
            list.add(String.valueOf(devices.get(j).getDev_price())!=null?String.valueOf(devices.get(j).getDev_price()):"");
            list.add(devices.get(j).getDev_purpose()!=null?devices.get(j).getDev_purpose():"");
            list.add(devices.get(j).getDev_bookid()!=null?devices.get(j).getDev_bookid():"");
            list.add(devices.get(j).getUser().getUser_name()!=null?devices.get(j).getUser().getUser_name():"");//責任人
            list.add(devices.get(j).getDev_protime()!=null?devices.get(j).getDev_protime():"");
            list.add(devices.get(j).getDev_booktime()!=null?devices.get(j).getDev_booktime():"");
            list.add(devices.get(j).getDev_usetime()!=null?devices.get(j).getDev_usetime():"");
            list.add(devices.get(j).getDev_settime()!=null?devices.get(j).getDev_settime():"");
            list.add(devices.get(j).getDev_retime()!=null?devices.get(j).getDev_retime():"");
            list.add(devices.get(j).getDev_dumptime()!=null?devices.get(j).getDev_dumptime():"");
            list.add(devices.get(j).getDev_remark()!=null?devices.get(j).getDev_remark():"");
            createTableRow(list, (short) j,demoSheet);
        }
        return demoSheet;
    }

    /**
     * 輸出
     * @param os
     * @param tableHeader
     * @throws IOException
     */
    public void exportExcel(OutputStream os,String [] tableHeader,HSSFWorkbook demoWorkBook) throws IOException {
        HSSFSheet sheet = createExcelSheet(tableHeader,demoWorkBook);
        sheet.setGridsPrinted(true);
        HSSFFooter footer = sheet.getFooter();
        footer.setRight("Page " + HSSFFooter.page() + " of " + HSSFFooter.numPages());
        demoWorkBook.write(os);
    }

     public  String exportExcels(String[] tableHeader,HttpServletRequest request) {
         HSSFWorkbook demoWorkBook = new HSSFWorkbook();
         //SimpleDateFormat df = new SimpleDateFormat("HH:mm:ss");
        String fileName="devicess.xls";
        request=ServletActionContext.getRequest();
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(request.getRealPath("/export")+"/"+fileName);
            exportExcel(fos,tableHeader,demoWorkBook);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                fos.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        return fileName;
    }

這個例子是直接在struts2的action上面實現的。首先是創建一個sheet，在sheet裏面創建第一行作爲表頭，表頭裏面的文字作爲一個字符串數組參數傳出去，可以不停的更換。然後就是創建單元格和往單元格里面放數值，device是我這個例子用到的實體類，這個就不給出來了，實際上隨便放一個字符串或者其他都是可以的。組裝成一個完整的excel表格，那麼就要寫入到項目裏面（這裏文件名是固定的），例子是寫到export這個目錄上面的，然後就是寫個下載的方法去調用就OK了。