FileInputStream in = new FileInputStream(paths+"/service/exportexl/yc.xls");
  
    wb = Workbook.getWorkbook(in);
 
   OutputStream os = response.getOutputStream();
   WritableWorkbook wwb = Workbook.createWorkbook(os,wb);
   WritableSheet ws = wwb.createSheet("Sheet1", 0);
   System.out.println(ws+"xxxx");
   //设置列宽
   for(int i=0;i<8;i++){
    ws.setColumnView(i,30);
   }
   SapBen sb=new SapBen();

  WritableCell cell = ws.getWritableCell(0,1);
 
   CellFormat cf = cell.getCellFormat();
    Label lab = new Label(0,1,"单位:" );
    lab.setCellFormat(cf);
   
      ws.addCell(lab);   --- 这行报错为空指针异常异常Excel