java导出excel如何设置单元格样式为文本样式

//新增的四句话，设置CELL格式为文本格式   
HSSFCellStyle cellStyle2 = demoWorkBook.createCellStyle();   
HSSFDataFormat format = demoWorkBook.createDataFormat();   
cellStyle2.setDataFormat(format.getFormat("@"));   
cell.setCellStyle(cellStyle2);   
cell.setCellValue(cells.get(i));    
cell.setCellType(HSSFCell.CELL_TYPE_STRING); 



//设置本列只能输入数字
sheet.createRow(0).createCell(0).setCellValue("本列只允许输入数字"); 
            CellRangeAddressList regions = new CellRangeAddressList(1, 65535, 0, 0);//设置范围 
DVConstraint constraint = DVConstraint.createNumericConstraint(DVConstraint.ValidationType.INTEGER, DVConstraint.OperatorType.BETWEEN, "0", "10");//设置格式 
HSSFDataValidation dataValidate = new HSSFDataValidation(regions, constraint); 
dataValidate.createErrorBox("error", "You must input a number between 0 to 10."); 
sheet.addValidationData(dataValidate);