把UTF8编码转换为GB2312编码[转]

如果只有某个页的编码需要修改，ASP.net 中则可以简单的使用下面代码：

Encoding gb2312 = Encoding.GetEncoding("gb2312");
Response.ContentEncoding = gb2312;

在非ASP.net 应用中，可能你读到的数据是UTF-8编码，但是你要转换为GB2312编码，则可以参考以下代码：

string utfinfo = "document.write(\"alert('aa你好么？？');\");";
string gb2312info = string.Empty;

Encoding utf8 = Encoding.UTF8;
Encoding gb2312 = Encoding.GetEncoding("gb2312");

// Convert the string into a byte[].
byte[] unicodeBytes = utf8.GetBytes(utfinfo);
// Perform the conversion from one encoding to the other.
byte[] asciiBytes = Encoding.Convert(utf8, gb2312, unicodeBytes);
            
// Convert the new byte[] into a char[] and then into a string.
// This is a slightly different approach to converting to illustrate
// the use of GetCharCount/GetChars.
char[] asciiChars = new char[gb2312.GetCharCount(asciiBytes, 0, asciiBytes.Length)];
gb2312.GetChars(asciiBytes, 0, asciiBytes.Length, asciiChars, 0);
gb2312info = new string(asciiChars);

当然，其他各种编码之间的转换，跟上述代码也类似的，就不描述了。

http://www.cnblogs.com/hesicong/archive/2005/08/17/217109.html