c# 字符串操作的性能測試 未知編碼 byte[] 轉 string

這個測試包含

1、while for 循環語句的測試；
2、StringBuilder 追加字符方法的測試；
       Insert 和 Append
3、byte的相關方法；
      BitConverter類byte[] 轉換的集合，

using System;
using System.Collections.Generic;
//using System.Linq;
using System.Text;
using System.Threading;
using System.IO;
namespace aMao.Common
{
    class Program
    {
        static void Main(string[] args)
        {
            StringBuilder sb=new StringBuilder();
            int m=0;
            //控制字節長度
            while (m++<1)
            {
                sb.AppendFormat("當前時間");
            }
            //被測方法循環次數
            int n=200000;
            string t="";
            byte[] bs=System.Text.Encoding.Default.GetBytes(sb.ToString());
            //byte本身的toString()方法 
            DateTime tm=DateTime.Now;
            for (int j=0; j<n; j++)
            {
                t=byteToString(bs);
            }
            Console.WriteLine("byteToString "+((DateTime)DateTime.Now-tm).TotalMilliseconds);
            Console.WriteLine(t);
            //遍歷添加到stringbuilder for insert
            tm=DateTime.Now;
            for (int j=0; j<n; j++)
            {
                t=byteTostring_for_insert(bs);
            }
            Console.WriteLine("byteTostring_for_insert HEX_TABLE "+((DateTime)DateTime.Now-tm).TotalMilliseconds);
            Console.WriteLine(t);
            //遍歷添加到stringbuilder while append 
            tm=DateTime.Now;
            for (int j=0; j<n; j++)
            {
                t=byteTostring_while_Append(bs);
            }
            Console.WriteLine("byteTostring_while_Append HEX_TABLE "+((DateTime)DateTime.Now-tm).TotalMilliseconds);
            Console.WriteLine(t);
            //遍歷添加到stringbuilder for append 
            tm=DateTime.Now;
            for (int j=0; j<n; j++)
            {
                t=byteTostring_for_Append(bs);
            }
            Console.WriteLine("byteTostring_for_Append HEX_TABLE "+((DateTime)DateTime.Now-tm).TotalMilliseconds);
            Console.WriteLine(t);
            //直接使用自帶BitConverter 
            tm=DateTime.Now;
            for (int j=0; j<n; j++)
            {
                t=BitConverter.ToString(bs);
            }
            Console.WriteLine("BitConverter "+((DateTime)DateTime.Now-tm).TotalMilliseconds);
            Console.WriteLine(t);
            /*******測試while　和　for**********/
            tm=DateTime.Now;
            whileRun(n * n);
            Console.WriteLine("whileRun  "+((DateTime)DateTime.Now-tm).TotalMilliseconds);
            tm=DateTime.Now;
            forRun(n * n);
            Console.WriteLine("forRun "+((DateTime)DateTime.Now-tm).TotalMilliseconds);
            tm=DateTime.Now;
            /*****************/
            Console.ReadLine();
        }
        const string HEX_TABLE="0123456789abcdef";
        // static char[] HEX_TABLE="0123456789abcdef".ToCharArray();
        public static string byteTostring_for_Append(byte[] b)
        {
            StringBuilder sb=new StringBuilder();
            int n=b.Length;
            int tmp;
            for (int i=0; i<n; i++)
            {
                tmp=b[i];
                sb.Append(HEX_TABLE[tmp>>4]);
                sb.Append(HEX_TABLE[tmp&0xf]);
            }
            return sb.ToString();
        }
        public static string byteTostring_while_Append(byte[] b)
        {
            StringBuilder sb=new StringBuilder();
            int n=b.Length;
            int tmp;
            /***/
            int i=0;
            while (i<n)
            {
                tmp=b[i];
                sb.Append(HEX_TABLE[tmp>>4]);
                sb.Append(HEX_TABLE[tmp&0xf]);
                i++;
            }
            /***/
            return sb.ToString();
        }
        public static string byteTostring_for_insert(byte[] b)
        {
            StringBuilder sb=new StringBuilder();
            int n=b.Length;
            int tmp;
            int idx=0;
            for (int i=0; i<n; i++)
            {
                tmp=b[i];
                sb.Insert(idx++, HEX_TABLE[tmp>>4]);
                sb.Insert(idx++, HEX_TABLE[tmp&0xf]);
            }
            return sb.ToString();
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="b"></param>
        /// <returns></returns>
        public static string byteToString(byte[] b)
        {
            StringBuilder sb=new StringBuilder();
            int n=b.Length;
            for (int i=0; i<n; i++)
            {
                sb.Append(b[i].ToString("x").PadLeft(2, '0'));
            }
            return sb.ToString();
        }
        public static string byteTostring(byte[] b, byte bt_key)
        {
            StringBuilder sb=new StringBuilder();
            int n=b.Length;
            int tmp;
            int idx=0;
            for (int i=0; i<n; i++)
            {
                tmp=(b[i]^bt_key);
                sb.Insert(idx++, HEX_TABLE[tmp>>4]);
                sb.Insert(idx++, HEX_TABLE[tmp&0xf]);
            }
            return sb.ToString();
        }
        public static void whileRun(int n)
        {
            int i=0;
            while (i<n)
            {
                i++;
            }
        }
        public static void forRun(int n)
        {
            for (int i=0; i<n; i++)
            {
            }
        }
        public static bool ValidateRight(int iAllRight, int iCurrRight)
        {
            if (iAllRight==(iAllRight|iCurrRight))
                return true;
            return false;
        }
    }
}

輸出結果：
byteToString 941.3536
b5b1c7b0cab1bce4
byteTostring_for_insert HEX_TABLE 590.8496
b5b1c7b0cab1bce4
byteTostring_while_Append HEX_TABLE 180.2592
b5b1c7b0cab1bce4
byteTostring_for_Append HEX_TABLE 190.2736
b5b1c7b0cab1bce4
BitConverter 80.1152
B5-B1-C7-B0-CA-B1-BC-E4
whileRun  4977.1568
forRun 5147.4016

結論
1、while for 循環語句的測試；
       執行了40000000000次空循環有些差距，但有時竟然速度相同。所以while for基本任意用。
2、StringBuilder 追加字符方法的測試；
       Insert 和 Append ，append方法速度快。
3、byte的相關方法；
      BitConverter類byte[] 轉換的集合，MS提供的方法速度很快，但出來的字符串 把byte[] 以‘-’分隔，如果進行replace("-","")操作，沒有自定義方法快，並且byte[]越大效率越低。

自定義的方法比較，明天再寫^_*