java读取Excel文件

public void readExcel(MultipartFile file,HttpServletResponse respon) throws IOException{
            POIFSFileSystem sf=new POIFSFileSystem(file.getInputStream());
            HSSFWorkbook book=new HSSFWorkbook(sf);
            HSSFSheet sheet=book.getSheetAt(0); 
            int row=sheet.getLastRowNum();
            HSSFRow rowObj=null;
            for(int i=0;i<=row;i++){
                rowObj=sheet.getRow(i);
                if(null!=rowObj&&null!=rowObj.getCell(0)&&StringUtils.isNotBlank(getValue(rowObj.getCell(0)))){
                    HSSFCell cell=rowObj.getCell(0);
                    String str=getValue(cell);
                }
                
            }
        }
        
        public String getValue(HSSFCell cell){
            DecimalFormat df = new DecimalFormat("0");
            String value="";
            if(null!=cell&&StringUtils.isNotBlank(cell.toString())){
                switch(cell.getCellType()){
                case HSSFCell.CELL_TYPE_NUMERIC :
                    value = df.format(cell.getNumericCellValue());
                    break;
                case HSSFCell.CELL_TYPE_STRING :
                    value = cell.getRichStringCellValue().getString();
                    break;
                case HSSFCell.CELL_TYPE_FORMULA :
                    value = cell.getCellFormula();
                    break;
                }
            }
            return value;
        }