java时间格式转换任意格式

例如：20180918/120023转换成2018-09-18 12:00:23

    //时间格式转换
    public String getNomalTime(String oldTime){
        String newTime = "";
        if(StringUtils.isNotBlank(oldTime)){
            String reg = "(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})";
            newTime = oldTime.replace("/","").replaceAll(reg, "$1-$2-$3T$4:$5:$6");
        }

        return  newTime;
    }