POI导出excel学习

 　　/**
     * 将集合转化为Excel表格
     */
    public void getExcel(List<List<String>> list) throws IOException {
        //1.标题
        String[] title = {"招聘名称", "投递邮箱", "信息来源", "信息城市", "来源网站"};
        //2.文件名
        String fileName = new String("企业邮箱信息.xls".getBytes(), "utf-8");
        //3.sheet名
        String sheetName = new String("梧桐果、海投网、我司企业邮箱信息".getBytes(), "utf-8");

        // 1.创建一个HSSFWorkbook，对应一个Excel文件
        HSSFWorkbook hssfWorkbook = new HSSFWorkbook();
        // 2.在workbook中添加一个sheet,对应Excel文件中的sheet
        HSSFSheet sheet = hssfWorkbook.createSheet(sheetName);
        // 3.在sheet中添加表头第0行,也就是标题行
        HSSFRow row = sheet.createRow(0);
        // 4.创建单元格，并设置单元格格式
        HSSFCellStyle cellStyle = hssfWorkbook.createCellStyle();
        cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);//样式为中心水平对齐
        
        //5.创建列单元格
        for (int i = 0; i < title.length; i++) {
            HSSFCell cell = row.createCell(i);
            cell.setCellValue(title[i]);
            cell.setCellStyle(cellStyle);
        }//表头

        for (int y = 0; y < list.size(); y++) {
            HSSFRow row1 = sheet.createRow(y + 1);//创建行
            List<String> strings = list.get(y);
            for (int x = 0; x < title.length; x++) {
                HSSFCell cell = row1.createCell(x);
                cell.setCellValue(strings.get(x));
                cell.setCellStyle(cellStyle);//创建列
            }
        }

        File file = new File("C:\\Users\\bxk\\Desktop\\" + fileName);
        OutputStream outputStream = new FileOutputStream(file);
        hssfWorkbook.write(outputStream);
        outputStream.flush();
        outputStream.close();
    }

        //1.标题
        String[] title = {"招聘名称", "投递邮箱", "信息来源", "信息城市", "来源网站"};
        //2.文件名
        String fileName = new String("企业邮箱信息.xls".getBytes(), "utf-8");
        //3.sheet名
        String sheetName = new String("梧桐果、海投网、我司企业邮箱信息".getBytes(), "utf-8");

 HSSFWorkbook hssfWorkbook = new HSSFWorkbook(); //对应一个Excel文件

HSSFWorkbook wb = new XSSFWorkbook(); try (OutputStream fileOut = new FileOutputStream("workbook.xlsx")) { wb.write(fileOut); }

HSSFSheet sheet = hssfWorkbook.createSheet(sheetName);//对应Excel文件中的sheet   其中sheetName不能为 "" ，不能为 Null

String safeName = WorkbookUtil.createSafeSheetName("");//这样创建的sheetName ""会转化为empty，null会转化为“null”