public boolean hasNext() {

        if (this.rowNum == 0 || this.currentRowNo >= this.rowNum) {

            try {
                book.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return false;
        } else {
            // sheet下一行内容为空判定结束
            if ((sheet.getRow(currentRowNo))[0].getContents().equals(""))
                return false;
            return true;
        }
    }