C#Unicode编码不可逆，Default也不可逆

不可逆：4个e

unsafe static void Main(string[] args)
 {
 byte[] by = new byte[256];
 for (int i = 0; i < by.Length; i++)
 by[i] = (byte)i;
 string s = Encoding.Unicode.GetString(by);
 byte[] by2 = Encoding.Unicode.GetBytes(s);
 for (int i = 0; i < by.Length; i++)
 {
 if (by[i] != by2[i])
 {
 Console.Write('e');
 }
 }

 Console.ReadKey();
 }
 不 可逆：
 unsafe static void Main(string[] args)
 {
 byte[] by = new byte[256];
 for (int i = 0; i < by.Length; i++)
 by[i] = (byte)(i + 200);
 string s = Encoding.Default.GetString(by);
 byte[] by2 = Encoding.Default.GetBytes(s);
 for (int i = 0; i < by.Length; i++)
 {
 if (by[i] != by2[i])
 {
 Console.Write('e');
 }
 }

 Console.ReadKey();
 }