Gb2312及Gb2312转Utf-8编码的UrlEncode编码解码（全）

为了一个gb2312下post中文参数到utf-8页面的程序，随闷的难受，查了一下午资料，大部分是讲Gb2312传到Gb2312页面的UrlEncode，没有提供到Utf-8页面的UrlEncode，后来找到Unicode转Utf-8码的资料，参考之下，终于写出了Utf-8的UrlEncode，这里整理下各种UrlEncode方法，供有需要的朋友参考。

详细Utf-8编码规则请百度一下。

Unicode 与 Utf-8码间的内码规则模板为：
原始码（16进制）　UTF－8编码（二进制）
--------------------------------------------
0000 - 007F       0xxxxxxx
0080 - 07FF       110xxxxx 10xxxxxx
0800 - FFFF       1110xxxx 10xxxxxx 10xxxxxx   （中文字在此区间)
……
--------------------------------------------

例如：
百度中查询“中国人”，会将中文URL参数转为Gb2312码的16进制表示，一个中文字用2个字节
http://www.baidu.com/s?wd=%D6%D0%B9%FA%C8%CB
Google中查询“中国人”，会将中文URL参数转为Utf-8编码的16进制表示，一个中文字用3个字节
http://www.google.cn/search?client=opera&rls=en&q=%E4%B8%AD%E5%9B%BD%E4%BA%BA&sourceid=opera&ie=utf-8&oe=utf-8

 

' Url编码，Gb2312页面之间传递参数
Function  URLEncode_Gb(ByVal str)
     Dim  i,s
     Dim  B,bCode,gb,Hight8b,Low8b
    s  =   ""
     For  i  =   1   To   Len (str)
        B  =   Mid (str,i, 1 )
        bCode = Abs ( Asc (B))
         If  (bCode >= 48   And  bCode <= 57 )  Or  (bCode >= 65   And  bCode <= 90 )  Or  (bCode >= 97   And  bCode <= 122 )  Or  bCode = 42   Or  bCode = 45   Or  bCode = 46   Or  bCode = 64   Or  bCode = 95   Then  
             ' 48 to 57代表0~9;65 to 90代表A~Z;97 to 122代表a~z
             ' 42代表*;46代表.;64代表@;45代表-;95代表_ 
            s = s  &  B
         ElseIf  bCode = 32   Then   ' 空格转成+
            s = s  &   " + "
         ElseIf  bCode < 128   Then      ' 低于128的Ascii转成1个字节
            s = s  &   " % "   &   Right ( " 00 "   &   Hex (bCode), 2 )
         Else  
            gb  =   Asc (B)
             If  gb  <   0   Then
                gb  =  gb  +   & H10000     ' gb编码为负数，要加上65536
             End   If
            Hight8b  =  (gb   And   & HFF00)  /   & H100     ' 二进制高8位
            Low8b  =  gb  And   & HFF     ' 二进制低8位
            s  =  s  &   " % "   &   Hex (Hight8b)  &    " % "   &   Hex (Low8b)
         End   If   
     Next
    URLEncode_Gb  =  s
End Function

' Url解码，Gb2312页面之间传递参数
Function  URLDecode_Gb(ByVal str)
     Dim  i,s
     Dim  B,bCode,gb,Hight8b,Low8b
    s  =   ""
     For  i  =   1   To   Len (str)
        B  =   Mid (str,i, 1 )
         Select   Case  B
             Case   " + "
                s = s  &   "   "
             Case   " % "
                gb = Mid (str,i + 1 , 2 )
                bCode = CInt ( " &H "   &  gb)
                 If  bCode < 128   Then
                    i = i + 2
                 Else
                    bCode = CInt ( " &H "   &  gb  &   Mid (str,i + 4 , 2 ))
                    i = i + 5
                 End   If  
                s = s  &   Chr (bCode)
             Case   Else
                s = s  &  B
         End   Select  
     Next
    URLDecode_Gb  =  s
End Function

' URL编码，Gb2312页面提交到Utf-8页面
Function  UrlEncode_GBToUtf8(ByVal str)
     Dim  B                     ' 单个字符
     Dim  ub                   ' 中文字的Unicode码(2字节)
     Dim  High8b, Low8b        ' Unicode码的高低位字节
     Dim  UtfB1, UtfB2, UtfB3  ' Utf-8码的三个字节
     Dim  i, s
     For  i  =   1   To   Len (str)
        B = Mid (str, i,  1 )
        ub  =  AscW(B)
         If  (ub >= 48   And  ub <= 57 )  Or  (ub >= 65   And  ub <= 90 )  Or  (ub >= 97   And  ub <= 122 )  Or  ub = 42   Or  ub = 45   Or  ub = 46   Or  ub = 64   Or  ub = 95   Then  
             ' 48 to 57代表0~9;65 to 90代表A~Z;97 to 122代表a~z
             ' 42代表*;46代表.;64代表@;45代表-;95代表_ 
            s = s  &  B
         ElseIf  ub = 32   Then   ' 空格转成+
            s = s  &   " + "
         ElseIf  ub < 128   Then      ' 低于128的Ascii转成1个字节
            s = s  &   " % "   &   Right ( " 00 "   &   Hex (ub), 2 )
         Else
            High8b  =  (ub  And   & HFF00)  /   & H100  ' Unicode码高位
            Low8b  =  ub  And   & HFF  ' Unicode码低位
            UtfB1  =  (High8b  And   & HF0)  /   & H10  Or   & HE0  ' 取Unicode高位字节的二进制的前4位 + 11100000
            UtfB2  =  ((High8b  And   & HF)  *   & H4  +  (Low8b  And   & HC0)  /   & H40)  Or   & H80  ' 取Unicode高位字节的后4位及低位字节的前2位 +10000000
            UtfB3  =  (Low8b  And   & H3F)  Or   & H80  ' 取Unicode低位字节的二进制后6位 + 10000000
            s  =  s  &   " % "   &   Hex (UtfB1)  &   " % "   &   Hex (UtfB2)  &   " % "   &   Hex (UtfB3)
         End   If
     Next
    UrlEncode_GBToUtf8  =  s
End Function



' “汉”－AscW("汉")=27721(十进制)    01101100 01001001(二进制)     6C49(十六进制)
' 将Gb2312码转成Utf-8码（十六进制表示）的方法为，先用AscW将Gb2312转为Unicode码(2字节),再'将Unicode码的二进制中的位按utf-8(3字节）模板规则填充 x 位：

' URL解码，Gb2312页面提交到Utf-8页面
Function  UrlDecode_GBToUtf8(ByVal str)
     Dim  B,ub     ' 中文字的Unicode码(2字节)
     Dim  UtfB     ' Utf-8单个字节
     Dim  UtfB1, UtfB2, UtfB3  ' Utf-8码的三个字节
     Dim  i, n, s
    n = 0
    ub = 0
     For  i  =   1   To   Len (str)
        B = Mid (str, i,  1 )
         Select   Case  B
             Case   " + "
                s = s  &   "   "
             Case   " % "
                ub = Mid (str, i  +   1 ,  2 )
                UtfB  =   CInt ( " &H "   &  ub)
                 If  UtfB < 128   Then  
                    i = i + 2
                    s = s  &  ChrW(UtfB)
                 Else  
                    UtfB1 = (UtfB  And   & H0F)  *   & H1000     ' 取第1个Utf-8字节的二进制后4位
                    UtfB2 = ( CInt ( " &H "   &   Mid (str, i  +   4 ,  2 ))  And   & H3F)  *   & H40         ' 取第2个Utf-8字节的二进制后6位
                    UtfB3 = CInt ( " &H "   &   Mid (str, i  +   7 ,  2 ))  And   & H3F         ' 取第3个Utf-8字节的二进制后6位
                    s = s  &  ChrW(UtfB1  Or  UtfB2  Or  UtfB3)
                    i = i + 8
                 End   If  
             Case   Else      ' Ascii码
                s = s  &  B
         End   Select  
     Next
    UrlDecode_GBToUtf8  =  s
End Function

' URL编码，Gb2312页面提交到Utf-8页面，另一种位计算方法
Private   Function  UrlEncode_GBToUtf8_V2(szInput) 
     Dim  wch, uch, szRet 
     Dim  x 
     Dim  nAsc, nAsc2, nAsc3 
     If  szInput  =   ""   Then  
        UrlEncode_GBToUtf8_V2 =  szInput 
         Exit   Function  
     End   If  
     For  x  =   1   To   Len (szInput) 
        wch  =   Mid (szInput, x,  1 ) 
        nAsc  =  AscW(wch) 
         If  nAsc  <   0   Then  nAsc  =  nAsc  +   65536  
         If  (nAsc  And   & HFF80)  =   0   Then  
            szRet  =  szRet  &  wch 
         Else  
             If  (nAsc  And   & HF000)  =   0   Then  
                uch  =   " % "   &   Hex (((nAsc    2   ^   6 ))  Or   & HC0)  &   Hex (nAsc  And   & H3F  Or   & H80) 
                szRet  =  szRet  &  uch 
             Else  
                uch  =   " % "   &   Hex ((nAsc    2   ^   12 )  Or   & HE0)  &   " % "   &  _ 
                 Hex ((nAsc    2   ^   6 )  And   & H3F  Or   & H80)  &   " % "   &  _ 
                 Hex (nAsc  And   & H3F  Or   & H80) 
                szRet  =  szRet  &  uch 
             End   If  
         End   If  
     Next  
    UrlEncode_GBToUtf8_V2 =  szRet 
End Function



' VB下用API方法的Unicode转Utf-8方法：
Private  Declare  Function  WideCharToMultiByte Lib  " kernel32 "  (ByVal CodePage  As   Long , ByVal dwFlags  As   Long , ByVal lpWideCharStr  As   Long , ByVal cchWideChar  As   Long , ByRef lpMultiByteStr  As  Any, ByVal cchMultiByte  As   Long , ByVal lpDefaultChar  As   String , ByVal lpUsedDefaultChar  As   Long )  As   Long
Private  Declare  Function  MultiByteToWideChar Lib  " kernel32 "  (ByVal CodePage  As   Long , ByVal dwFlags  As   Long , ByVal lpMultiByteStr  As   Long , ByVal cchMultiByte  As   Long , ByVal lpWideCharStr  As   Long , ByVal cchWideChar  As   Long )  As   Long
Private   Const  CP_UTF8  =   65001


Function  Utf8ToUnicode(ByRef Utf()  As   Byte )  As   String
     Dim  lRet  As   Long
     Dim  lLength  As   Long
     Dim  lBufferSize  As   Long
    lLength  =   UBound (Utf)  -   LBound (Utf)  +   1
     If  lLength  <=   0   Then   Exit   Function
    lBufferSize  =  lLength  *   2
    Utf8ToUnicode  =   String $(lBufferSize,  Chr ( 0 ))
    lRet  =  MultiByteToWideChar(CP_UTF8,  0 , VarPtr(Utf( 0 )), lLength, StrPtr(Utf8ToUnicode), lBufferSize)
     If  lRet  <>   0   Then
        Utf8ToUnicode  =   Left (Utf8ToUnicode, lRet)
     End   If
End Function

Function  UnicodeToUtf8(ByVal UCS  As   String )  As   Byte ()
     Dim  lLength  As   Long
     Dim  lBufferSize  As   Long
     Dim  lResult  As   Long
     Dim  abUTF8()  As   Byte
    lLength  =   Len (UCS)
     If  lLength  =   0   Then   Exit   Function
    lBufferSize  =  lLength  *   3   +   1
     ReDim  abUTF8(lBufferSize  -   1 )
    lResult  =  WideCharToMultiByte(CP_UTF8,  0 , StrPtr(UCS), lLength, abUTF8( 0 ), lBufferSize, vbNullString,  0 )
     If  lResult  <>   0   Then
    lResult  =  lResult  -   1
     ReDim  Preserve abUTF8(lResult)
    UnicodeToUtf8  =  abUTF8
     End   If
End Function