生成唯一code

    private String getCode() {
        List<String> ptypeCodeList = mapper.findCodeList();
        String code = "";
        for(int i=0;i<ptypeCodeList.size();i++) {
            code = "TY"+i;
            if(!ptypeCodeList.contains(code)) {
                return code;
            }
        }
        return "TY"+ptypeCodeList.size();
    }