Serial number of tools

@Component
public class CreateCodeUtil {

    @Resource
    private JdbcTemplate jdbcTemplate;

    public  String createCode(){
        //查询数据库中最大的流水号
        String sql = "select MAX(a.FILE_CODE+0) maxCode FROM t_file_info a";
        List<Map<String,Object>> list;
        //调用templet方法
        list = jdbcTemplate.queryForList(sql);
        String resultCode = "";
        String maxCode = "";
        Object object = list.get(0).get("maxCode");
        if (list.size() > 0 && object!=null) {
            maxCode =  new DecimalFormat("0").format((double)object);
        //Specify the generated time format
        }
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd"); 
        String preCode = simpleDateFormat.format(new Date()); 
        //If there is a code generated that day, add 1 to the end number directly; if a new code is not generated directly 
        if (maxCode!=null&&maxCode.contains(preCode)){ 
            Integer endCode = Integer.parseInt(maxCode.substring(8)); 
            //Calculation result 
            endCode = endCode+10000+1; 
            resultCode = preCode+endCode.toString(). substring(1); 
        }else { 
            resultCode = preCode+"0001"; 
        } 
        return resultCode; 
    } 
}