正则与普通方法对字符串过滤的比较

一、字符串替换类中的两个方法

 

 #region 使用正则进行替换
        /// <summary>
        /// 使用正则进行替换
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string RegFilter(string str)
        {
            string output = "";
            string pattern = @"*|and|exec|insert|select|delete|update|count|master|truncate|declare|char(|mid(|chr(|'";
            output = Regex.Replace(str, Regex.Escape(pattern), "", RegexOptions.IgnoreCase | RegexOptions.Compiled);
            return output;
        }
        #endregion
        #region 使用循环替换的方式
        /// <summary>
        /// 使用循环替换的方式
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string Filter(string str)
        {
            string output = "";
            string[] pattern =
            {
                "select", "insert", "delete", "from", "count\(", "drop table", "update", "truncate",
                "asc\(", "mid\(", "char\(", "xp_cmdshell", "exec   master", "netlocalgroup administrators",
                "net user", "or ", " or ", " or", "and"
            };
            for (int i = 0; i < pattern.Length; i++)
            {
                output = str.Replace(pattern[i].ToString(), "");
            }
            return output;
        }
        #endregion  

二、执行方法：

   

 static void Main(string[] args)
        {
            string inputStr = @"ldklskdkfjlkinsertkkldslklkdlkldorkldklkkkdkklklorslect from  kklsdklklksdlfromklksdlfjlkjskldflklkljflk*fromlikemeklkl kkwkwk kdkkjlkjlsdjf insert    from  oklkdllkjlkjlfjlj woinsert      iselect 8 kldjlfjlkjlkjsdkljlkfjkkk and  or  not  in kdlkjsdlfkjlk in herre lkldskjflkjlkjlkjlsdkjfljlk546546413625131651325131315143251313";
            StringBuilder stringBuilder1=new StringBuilder();
            StringBuilder stringBuilder2 = new StringBuilder();
            Stopwatch stopwatch=new Stopwatch();
            Stopwatch stopwatch2 = new Stopwatch();
            stopwatch.Start();
            for (int i = 0; i < 100000; i++)
            {
                stringBuilder1.Append(StringHelper.RegFilter(inputStr));
            }
            stopwatch.Stop();
            Console.WriteLine("正则方法过滤所用时间："+stopwatch.ElapsedMilliseconds);
            
            stopwatch2.Start();
            for (int i = 0; i < 100000; i++)
            {
                stringBuilder2.Append(StringHelper.Filter(inputStr));
            }
            stopwatch2.Stop();
            Console.WriteLine("普通方法过滤所用时间：" + stopwatch2.ElapsedMilliseconds);
            Console.ReadKey();
        }  

三、执行结果：

四、结论：

正则的方式要快很多

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来自为知笔记(Wiz)