转载>>ASCII、UTF8、Uncicode编码下的中英文字符大小

• ASCII不能保存中文

• UTF8是变长编码。在对ASCII字符编码时，UTF更省空间，只占1个字节，与ASCII编码方式和长度相同；Unicode在对ASCII字符编码时，占用2个字节，且第2个字节补零。

• UTF8在对中文编码时需要占用3个字节；Unicode对中文编码则只需要2个字节。

 

代码示例：

 1 private static void ShowCode() { 2     string[] strArray = { "b", "abcd", "乙", "甲乙丙丁" }; 3     byte[] buffer; 4     string mode, back; 5  6     foreach (string str in strArray) { 7  8         for (int i = 0; i <= 2; i++) { 9             if (i == 0) {10                 buffer = Encoding.ASCII.GetBytes(str);11                 back = Encoding.ASCII.GetString(buffer, 0, buffer.Length);12                 mode = "ASCII";13             } else if (i == 1) {14                 buffer = Encoding.UTF8.GetBytes(str);15                 back = Encoding.UTF8.GetString(buffer, 0, buffer.Length);16                 mode = "UTF8";17             } else {18                 buffer = Encoding.Unicode.GetBytes(str);19                 back = Encoding.Unicode.GetString(buffer, 0, buffer.Length);20                 mode = "Unicode";21             }22 23             Console.WriteLine("Mode: {0}, String: {1}, Buffer.Length: {2}",24                 mode, str, buffer.Length);25 26             Console.WriteLine("Buffer:");27             for (int j = 0; j <= buffer.Length - 1; j++) {28                 Console.Write(buffer[j] + " ");29             }30 31             Console.WriteLine("\nRetrived: {0}\n", back);32         }33     }34 }

运行结果：

 1 Mode: ASCII, String: b, Buffer.Length: 1 2 Buffer: 98 3 Retrived: b 4  5 Mode: UTF8, String: b, Buffer.Length: 1 6 Buffer: 98 7 Retrived: b 8  9 Mode: Unicode, String: b, Buffer.Length: 210 Buffer: 98 011 Retrived: b12 13 Mode: ASCII, String: abcd, Buffer.Length: 414 Buffer: 97 98 99 10015 Retrived: abcd16 17 Mode: UTF8, String: abcd, Buffer.Length: 418 Buffer: 97 98 99 10019 Retrived: abcd20 21 Mode: Unicode, String: abcd, Buffer.Length: 822 Buffer: 97 0 98 0 99 0 100 023 Retrived: abcd24 25 Mode: ASCII, String: 乙, Buffer.Length: 126 Buffer: 6327 Retrived: ?28 29 Mode: UTF8, String: 乙, Buffer.Length: 330 Buffer: 228 185 15331 Retrived: 乙32 33 Mode: Unicode, String: 乙, Buffer.Length: 234 Buffer: 89 7835 Retrived: 乙36 37 Mode: ASCII, String: 甲乙丙丁, Buffer.Length: 438 Buffer: 63 63 63 6339 Retrived: ????40 41 Mode: UTF8, String: 甲乙丙丁, Buffer.Length: 1242 Buffer: 231 148 178 228 185 153 228 184 153 228 184 12943 Retrived: 甲乙丙丁44 45 Mode: Unicode, String: 甲乙丙丁, Buffer.Length: 846 Buffer: 50 117 89 78 25 78 1 7847 Retrived: 甲乙丙丁

得出结论：

1 ASCII不能保存中文(貌似谁都知道=_-`)。2 UTF8是变长编码。在对ASCII字符编码时，UTF更省空间，只占1个字节，与ASCII编码方式和长度相同；Unicode在对ASCII字符编码时，占用2个字节，且第2个字节补零。3 UTF8在对中文编码时需要占用3个字节；Unicode对中文编码则只需要2个字节。