用poi进行模板下载，怎样设置某列为文本类型

private void caeateJobSheet(HSSFWorkbook workbook, HSSFSheet sheet)
throws Exception {
// 设置表头样式
HSSFCellStyle headStyle = workbook.createCellStyle();
HSSFFont headFont = workbook.createFont();
headFont.setFontHeightInPoints((short) 12);// 字号
headFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);// 加粗
headStyle.setFont(headFont);
headStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 左右居中
headStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 上下居中

    headStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);
    headStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);
    headStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN);
    headStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);
    headStyle.setTopBorderColor(HSSFColor.BLACK.index);
    headStyle.setLeftBorderColor(HSSFColor.BLACK.index);
    headStyle.setBottomBorderColor(HSSFColor.BLACK.index);
    headStyle.setRightBorderColor(HSSFColor.BLACK.index);

    // 创建行
    HSSFRow row = sheet.createRow(0);    //第一行

    HSSFCell cell_inst_no = row.createCell(0);
    cell_inst_no.setCellStyle(headStyle);
    cell_inst_no.setCellValue("学号");
    sheet.setColumnWidth(0, 7000);

    }

    图为下载的模板，想让学号一列为文本类型，应该怎样设置

http://blog.csdn.net/spp_1987/article/details/13770637