在项目开发过程中，经常会使用到c++ 的url编码和解码，本文将以此问题详细介绍使用技巧，需要的朋友可以参考下
代码如下：

#pragma once
#include iostream
#include string
#include windows.h
using namespace std;
class strCoding
{
public:
strCoding(void);
~strCoding(void);
void UTF_8ToGB2312(string &pOut, char *pText, int pLen);//utf_8转为gb2312
void GB2312ToUTF_8(string& pOut,char *pText, int pLen); //gb2312 转utf_8
string UrlGB2312(char * str); //urlgb2312编码
string UrlUTF8(char * str); //urlutf8 编码
string UrlUTF8Decode(string str); //urlutf8解码
string UrlGB2312Decode(string str); //urlgb2312解码
private:
void Gb2312ToUnicode(WCHAR* pOut,char *gbBuffer);
void UTF_8ToUnicode(WCHAR* pOut,char *pText);
void UnicodeToUTF_8(char* pOut,WCHAR* pText);
void UnicodeToGB2312(char* pOut,WCHAR uData);
char CharToInt(char ch);
char StrToBin(char *str);
};

代码如下：

#include "StdAfx.h"
#include "./urlcodeing.h"
//这是个类strCoding (strCoding.cpp文件)
strCoding::strCoding(void)
{
}
strCoding::~strCoding(void)
{
}
void strCoding::Gb2312ToUnicode(WCHAR* pOut,char *gbBuffer)
{
::MultiByteToWideChar(CP_ACP,MB_PRECOMPOSED,gbBuffer,2,pOut,1);
return;
}
void strCoding::UTF_8ToUnicode(WCHAR* pOut,char *pText)
{
char* uchar = (char *)pOut;
uchar[1] = ((pText[0] & 0x0F) 4) + ((pText[1] 2) & 0x0F);
uchar[0] = ((pText[1] & 0x03) 6) + (pText[2] & 0x3F);
return;
}
void strCoding::UnicodeToUTF_8(char* pOut,WCHAR* pText)
{
// 注意 WCHAR高低字的顺序,低字节在前，高字节在后
char* pchar = (char *)pText;
pOut[0] = (0xE0 | ((pchar[1] & 0xF0) 4));
pOut[1] = (0x80 | ((pchar[1] & 0x0F) 2)) + ((pchar[0] & 0xC0) 6);
pOut[2] = (0x80 | (pchar[0] & 0x3F));
return;
}
void strCoding::UnicodeToGB2312(char* pOut,WCHAR uData)
{
WideCharToMultiByte(CP_ACP,NULL,&uData,1,pOut,sizeof(WCHAR),NULL,NULL);
return;
}

//做为解Url使用
代码如下：

char strCoding:: CharToInt(char ch){
if(ch='0' && ch='9')return (char)(ch-'0');
if(ch='a' && ch='f')return (char)(ch-'a'+10);
if(ch='A' && ch='F')return (char)(ch-'A'+10);
return -1;
}
char strCoding::StrToBin(char *str){
char tempWord[2];
char chn;
tempWord[0] = CharToInt(str[0]); //make the B to 11 -- 00001011
tempWord[1] = CharToInt(str[1]); //make the 0 to 0 -- 00000000
chn = (tempWord[0] 4) | tempWord[1]; //to change the BO to 10110000
return chn;
}

//UTF_8 转gb2312
代码如下：

void strCoding::UTF_8ToGB2312(string &pOut, char *pText, int pLen)
{
char buf[4];
char* rst = new char[pLen + (pLen 2) + 2];
memset(buf,0,4);
memset(rst,0,pLen + (pLen 2) + 2);
int i =0;
int j = 0;
while(i pLen)
{
if(*(pText + i) = 0)
{
rst[j++] = pText[i++];
}
else
{
WCHAR Wtemp;
UTF_8ToUnicode(&Wtemp,pText + i);
UnicodeToGB2312(buf,Wtemp);
unsigned short int tmp = 0;
tmp = rst[j] = buf[0];
tmp = rst[j+1] = buf[1];
tmp = rst[j+2] = buf[2];
//newBuf[j] = Ctemp[0];
//newBuf[j + 1] = Ctemp[1];
i += 3;
j += 2;
}
}
rst[j]='/0';
pOut = rst;
delete []rst;
}

//GB2312 转为 UTF-8
代码如下：

void strCoding::GB2312ToUTF_8(string& pOut,char *pText, int pLen)
{
char buf[4];
memset(buf,0,4);
pOut.clear();
int i = 0;
while(i pLen)
{
//如果是英文直接复制就可以
if( pText[i] = 0)
{
char asciistr[2]={0};
asciistr[0] = (pText[i++]);
pOut.append(asciistr);
}
else
{
WCHAR pbuffer;
Gb2312ToUnicode(&pbuffer,pText+i);
UnicodeToUTF_8(buf,&pbuffer);
pOut.append(buf);
i += 2;
}
}
return;
}

//把str编码为网页中的 GB2312 url encode ,英文不变，汉字双字节 如%3D%AE%88
代码如下：

string strCoding::UrlGB2312(char * str)
{
string dd;
size_t len = strlen(str);
for (size_t i=0;ilen;i++)
{
if(isalnum((BYTE)str[i]))
{
char tempbuff[2];
sprintf(tempbuff,"%c",str[i]);
dd.append(tempbuff);
}
else if (isspace((BYTE)str[i]))
{
dd.append("+");
}
else
{
char tempbuff[4];
sprintf(tempbuff,"%%%X%X",((BYTE*)str)[i] 4,((BYTE*)str)[i] %16);
dd.append(tempbuff);
}
}
return dd;
}

//把str编码为网页中的 UTF-8 url encode ,英文不变，汉字三字节 如%3D%AE%88
代码如下：

string strCoding::UrlUTF8(char * str)
{
string tt;
string dd;
GB2312ToUTF_8(tt,str,(int)strlen(str));
size_t len=tt.length();
for (size_t i=0;ilen;i++)
{
if(isalnum((BYTE)tt.at(i)))
{
char tempbuff[2]={0};
sprintf(tempbuff,"%c",(BYTE)tt.at(i));
dd.append(tempbuff);
}
else if (isspace((BYTE)tt.at(i)))
{
dd.append("+");
}
else
{
char tempbuff[4];
sprintf(tempbuff,"%%%X%X",((BYTE)tt.at(i)) 4,((BYTE)tt.at(i)) %16);
dd.append(tempbuff);
}
}
return dd;
}

//把url GB2312解码
代码如下：

string strCoding::UrlGB2312Decode(string str)
{
string output="";
char tmp[2];
int i=0,idx=0,ndx,len=str.length();
while(ilen){
if(str[i]=='%'){
tmp[0]=str[i+1];
tmp[1]=str[i+2];
output += StrToBin(tmp);
i=i+3;
}
else if(str[i]=='+'){
output+=' ';
i++;
}
else{
output+=str[i];
i++;
}
}
return output;
}

//把url utf8解码
代码如下：

string strCoding::UrlUTF8Decode(string str)
{
string output="";
string temp =UrlGB2312Decode(str);//
UTF_8ToGB2312(output,(char *)temp.data(),strlen(temp.data()));
return output;
}