最近在⼀个项⽬中要实现前端传递给我们客户端的是base64的图⽚数据流，我们需要做的就是将它转为图⽚并且保存起来，根据需要再将图⽚存储路径信息做进⼀步操作。
前端传过来的字符串是这样的：
<img src="data:image/jpg;base64,iVBORw0KGgoAAAANSUhEUgAAAKAAAAAwCAMAAAChd4FcAAAAA3NCSVQICAjb4U/gAAACRlBMVEUAAADi6OSMjIxSUlIrXja5trg8rFEDRhErokJ8w4pJrVxmZmYERRIinTn++P07nk/X0Naww7Stra0pdTj37/d BAsXzdni24VmC7MzMw1kEYzMzPZ4Nul1K6Wr5tWs2jp8eseaC0ufz5mZmaEoorI1cszpUkXTSJErFix2bi1tbVKSkp7e3skWC9wvn5zlHq6yL3S3dSXzqJBcEspKSnY6dxCQkLI486mvKulpaVAbUkTSx8ICAgjcDIhISHh7eM6Ojonnz1QsGP///+Dxo9R x5wYYcYyodmzViuHPFxcVEtFl5mH/V3def0qlhh2rZ7d7F2MiEhIQ4Z0Lv8+/F4csvo0QbUidAp1OEoIoqfDozZjOx27kOSho6mkw2j0iftaMyi0S2xroSUiBrvHuFx5J0v4Lm7+eNqJOc0KVBq1TU59gpoEBskXRzc3Pg2N6tubDe5d99nYRNr1+ZmZkbWyg9 0xbfAz8OtvbUhazC12ryJpY6+3sXD0MbE4MmJyJUgVCtSsmXQ5tWjuKd5wobd8OEfYy0ZUCS9vb3v7+8LRxgtgD0xZzw1j0cnWjJiimp2mX2An4aUtZye1qkYmjDm5ube3t7W1tbk9+fM5NA4lEombjRWfl9Ke1K2270xhUGbs6BrjnI7akSY1aSrvq+5yr1K R7MSAAAACXBIWXMAAAsSAAALEgHS3X78AAAAFnRFWHRDcmVhdGlvbiBUaW1lADAzLzI0LzEzWoVZMQAAABx0RVh0U29mdHdhcmUAQWRvYmUgRmlyZXdvcmtzIENTNXG14zYAAAt9SURBVFiFzZn/U9NoHsfDl3KFXgOWAQtUL0Kh7Ei 7jnJuyt685d2ivrCHg4ZvRPuydJW5ICCj/s6WeYJn1Kklfen29PnmDCJ27YAeMQwv8rx4G2DyAEyNAWR5uPT7kHEICs16vbL1pbW/vmzr+xfHTGDEAgHLuSe2biXu25c+dqSycmTpxcFj4uogoQwPFXgdKbG4vT9aJNL27cLHV3dkDwsegENSB4UBGo3 O12s0ofZJpLn4kE16K1nTuox1pHMeTBzy4i3Ju/As5AY8Q2WlAXPh5vXh0L55oxetzyqoDLl+4DHie4CC9FIccH4+JJA8uzEOhqAh9hzzPxWIwViTAeYJHv4HmC6Fvy1+/xuuqqurGq3DLkyfcUQFx4UXg1qV98ZBtrl/ZJcSX+t51NrMG1sCxlIaIGSlXHIJjf E3/ad7Vu+fvrV7dM7z/vOtoa2V8tPHjZqUoDwSuCnA/mmL90KbKe9AubGwdd3qTjQsC6KdRUhIArHb3f++fa8AXCGOCsCLgEDh3M2G+GiADi5A0LL5eDC6urO2WXQd7luZ67isD5OAoLT6wfrJ2t4PnXPYHsL3P8FASK9+FhMBEKAVcvVr/6mAZytSFJ t+Vbq334kQDBa/fN9/KhODzzIEmIP+h811fFulgNbWBZKi4ruNx6/0WzRmMjOBflWqIIQBk0bNxA2JCL37Q+f9FxBdxfPd1x9hh48UXF+Z9bD8knA0L61cX34yG7lz4naN6qAhoiTkO6qEiQkgJh112oAnRRDEI+znM8SoJ4PJ0kS1shrhnOz1dlXeaFJaF5/P AyMbEb4rkTpcZCFMlKF1m0G9y3RE3QOryR1EQWt7+mslXv7cgrlynD4hs/ICAOmhcZpa3H2pTIiDY2iPg2KlTGxlF8VKh+4l8Mohn2FobLii/p06+ZtlFxdX/AClKPlmMSvKqTa1gRUYEbpa6f/jBXfrZ6KhisPDH3/0sHQfXyloUVhYNkWQDaJhsStpkr6w03q
YSOpVlKwFB86NNZQovPj1z5djS0u25G/cK0yKeWnE/Kl+SLxz8g17PMD69Xj9rZfRDBUIZw7QUMLOzswxJarU+0ivJBKb0+UBWrJ1h9LumJdsAsGOVUtA6MI3Y+5yY2mJAATg+UahK19w3ssx1128syg4XJzVfVyWFhwmkQkFe71TLSNAamWqJ4n /NxPMrUNKTspbmAvFqUnW3qMoqOrUQKShun/do1u2jhHLvdBZUKzpUqXVn8aClJD+ZzV+rrF29dDDzbfiPsxoWoSY8VqQAakEZAjD/vWl6JpTcYIQuCwWAbXYB09Pms9ST69DHMTLt2cK1lKmntEfI/3ZJMYUQ0gPnt9mzYjRlAVpakS46JUMcg3ler 1u8bRFFmaQiBNnKyxUeS09Mk6Wuh6/Mm8wfzI+Tj/MHBwXrrlwnt4OQQigCrVqsdGhwm/2HThXWYqSvt0bgTM8QwTzbiM2BSVCqTpLNYAfjjs6x0FkL6n+tv39XBPVUL0hIgEAFx/PhQjdeLAGeD0Zcvo8HZKbp+2osuNSLHYIRpb9c2WRKJtYjVPJNI sR3k5TIBZb28qAFeUbRx/0GHZW1MhLSrYDmnc7BtEX4R8fWRtdLLFKp/BKgKKhadFny/eqwwIQ6FQCXOcDtF0DzmD4/yAKQ52Y7AbcwE+B8MGcjBPPBMwVwl4UdXG95lZQstkT03N9DT6qFnIK6ipebyGf1/TjgCZyPfIIsx+gIO9Pqs1DwUAST6MiA IJeE41EdqnJ+FtpNWKxBI/UcxZrUwUNTLRxdpJ88iIeVJycUhyca8ozrAIGGxoCgYX8iZLSu601ZBXgV+MPL8aELVAHRp1ZQAK9CtlDG5+XrX7D/Qv1fN7RbyamDk+Onp8Zq0NMbUlZiC80/SlddA8axXLo9VnRklSZjabm5jhfrTpYVCSTIqok0xb/gKN95 AALJ97tZvH937s/L+/gMxghBAkruhAulRmUBlfJAjOTL5jLRhbyyu40CJZpxieXGb1UZhIJbZMX5U/EOpI/G2yryfsTNqDDdJRJDaipxLBGtkutoVgHt0uVdfrmmdtJHlD3qLjwx3vu3JPHODUj+G62BM1LkmUGf6ltGvGVge8WvMP1d6ZHcLxhMD8/v3eYfNy itlQsvJSJ0kC2oxiZYQg1oV5OKgC3FJ3kpUb49LqB9j5/OIomtWIfeTt2Te0olJ767UtIlkSMN/X0uuLtmsLvJH6MpKJyv1NikF5N6oNRlPduOyllCQuBCiaA6PkLGaNpkYpoXmnTl2owdKNW6qJy6/uivvLy9V97pXF5PhG8cTE9bt1KRcLJUy9F6YAYaiA7F+ RbQmdNu8CKjMSIEFRRBdmJCgC78bscRsRp5ARyHhlqxOE1hX1zOqn2glkF28px06dmwgkeww9yTBm8dK4WR9E5WRKX4JcHhn67stgPekNTfse4knA79OApNKsEqDOtTs3MGZMFrrSTpbmg+fdKh8jWxwbW8wYurQRuC8B4u0+ckRGaPg30ggfW 3C8mkoNhKqMmXdhMHRpTS/0sUCPv+s+AOPTKIVn0gJH02kLtyfZIkmQNFf8VA0ahFsfCqfQmZvSgf11Bo1SYE3EtKDgGR7FvrUE1YB3A0UfvCZZCywuvtMsruCKB0v9Sw56LMqWXQ1+QfF3FjahfIOeixxNR72sUR+qgudWPmggE+/SccFoIxGNK ZicebLzrJEVJ2Yao4sDsW6TgTvco3vyubgjsPkBJ38WOJa+ZV1l2D+QDYwOe9ikA4QjJ1xZyTUONOaYnMI8ZhM8jpxGTxhQA357jkmcMAucqQsN6YDF2Wj3OyjKYQrzRwFEk9bAxvsIL321/jy9smDEUG9BH36PgWcNkm95O++sBIDFCB4BYnYAwi AaFQMTH2nrWZDfeL9CMw0DmQ+7JQB8ju7qrMpj2od4oxiMorIQN6DGhiMgB5ndOpM9nFpTrOg1qt0QQrHf7GRr8OhB1HXTwCodaJgzX8yl1BpxMRlTCUgNkYb88WhYw7nQD1J9bpTwOKjf+aCXQ7IOA9dsDxCNAoTqaAbgDdi/EaUvKICoqEFYHNfZ UVepgt1+l4LUBYOzy+3O6/CC7i5MAjSaBa3SgQw3A5emOHW75aHeFFQhzgdrCfUQcexp4rn5rAmIGlkZ+5VhDXHQvhTYwHkOhtsRxRZxQhB7Y+bj8b3wRjBGCEOelIQiKDCy6FCRsh1zCVKxRQ7BzIlBcmKHiWHHgm+VMf8BkYd2tg8l1DiD/QXkXS 2vcLM2kLvKHfZkv4Wp35NAkFVdccNdWlt8E1lt6cSjigv8J/SeRBARYfPWXF/n29zczr658cvwE3vTJJrUQHmeP9Iy3m9mB7zthJ/M287/AdxppEv2qVN4AAAAAElFTkSuQmCC" />
那么这是什么呢？这是Data URI scheme。
Data URI scheme是在RFC2397中定义的，⽬的是将⼀些⼩的数据，直接嵌⼊到⽹页中，从⽽不⽤再
从外部⽂件载⼊。⽐如上⾯那串字符，其实是⼀张⼩图⽚，将这些字符复制黏贴到⽕狐的地址栏中并转到，就能看到
它了，⼀张1X36的⽩灰png图⽚。
在上⾯的Data URI中，data表⽰取得数据的协定名称，image/png 是数据类型名称，base64 是数据的编码⽅法，逗号后⾯就是这个image/png⽂件base64编码后的数据。 ⽬前，Data URI scheme⽀持的类型有：
data:,⽂本数据
data:text/plain,⽂本数据
data:text/html,HTML代码
data:text/html;base64,base64编码的HTML代码
data:text/css,CSS代码
data:text/css;base64,base64编码的CSS代码
data:text/javascript,Javascript代码
data:text/javascript;base64,base64编码的Javascript代码
data:image/gif;base64,base64编码的gif图⽚数据
data:image/png;base64,base64编码的png图⽚数据
data:image/jpeg;base64,base64编码的jpeg图⽚数据
data:image/x-icon;base64,base64编码的icon图⽚数据
base64简单地说，它把⼀些 8-bit 数据翻译成标准 ASCII 字符，⽹上有很多免费的base64 编码和解码的⼯具，在PHP中可以⽤函数base64_encode() 进⾏编码，如echo base64_encode(file_get_contents(‘wg.png’));
⽬前，IE8、Firfox、Chrome、Opera浏览器都⽀持这种⼩⽂件嵌⼊。
举个图⽚的例⼦：
⽹页中⼀张图⽚可以这样显⽰：
<img src="mail.163/images/x.png"/>
也可以这样显⽰：
<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAJAQMAAADaX5RTAAAAA3NCSVQICAjb4U/gAAAABlBMVEX///+ZmZmOUEqyAAAAAnRSTlMA/1uRIrUAAAAJcEhZcwAACusAAArrAYKLDVoAAAAWdEVYdENy FWHRTb2Z0d2FyZQBBZG9iZSBGaXJld29ya3MgQ1M26LyyjAAAAB1JREFUCJljONjA8LiBoZyBwY6BQQZMAtlAkYMNAF1fBs/zPvcnAAAAAElFTkSuQmCC"/>
把图像⽂件的内容直接写在了HTML ⽂件中，这样做的好处是，节省了⼀个HTTP 请求。坏处是浏览器不会缓存这种图像。
Base64.h
#ifndef _BASE64_H_
铁水包#define _BASE64_H_
#include <string>
using namespace std;
class CBase64
{
public:
public:
CBase64();
~CBase64();
/*编码
DataByte
*/
std::string Encode(const char* Data, int DataByte);
/
*解码
DataByte
[in]输⼊的数据长度，以字节为单位
OutByte
[out]输出的数据长度，以字节为单位，请不要通过返回值计算
输出数据的长度
*/
std::string Decode(const char* Data, int DataByte, int& OutByte);
};
#endif//_BASE64_H_
Base64.cpp
#include"Base64.h"
CBase64::CBase64()
{
}
CBase64::~CBase64()
{
}
std::string CBase64::Encode(const char* Data, int DataByte)
{
//编码表
const char EncodeTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
//返回值
string strEncode;
unsigned char Tmp[4] = { 0 };
int LineLength = 0;
for (int i = 0; i<(int)(DataByte / 3); i++)
{
Tmp[1] = *Data++;
Tmp[2] = *Data++;
Tmp[3] = *Data++;
strEncode += EncodeTable[Tmp[1] >> 2];
strEncode += EncodeTable[((Tmp[1] << 4) | (Tmp[2] >> 4)) & 0x3F];
strEncode += EncodeTable[((Tmp[2] << 2) | (Tmp[3] >> 6)) & 0x3F];
strEncode += EncodeTable[Tmp[3] & 0x3F];
if (LineLength += 4, LineLength == 76) { strEncode += "\r\n"; LineLength = 0; }
}
//对剩余数据进⾏编码
int Mod = DataByte % 3;
if (Mod == 1)
{
Tmp[1] = *Data++;
strEncode += EncodeTable[(Tmp[1] & 0xFC) >> 2];
strEncode += EncodeTable[((Tmp[1] & 0x03) << 4)];
strEncode += "==";
}
else if (Mod == 2)
{
Tmp[1] = *Data++;
Tmp[2] = *Data++;
strEncode += EncodeTable[(Tmp[1] & 0xFC) >> 2];
strEncode += EncodeTable[((Tmp[1] & 0x03) << 4) | ((Tmp[2] & 0xF0) >> 4)];
strEncode += EncodeTable[((Tmp[2] & 0x0F) << 2)];
strEncode += "=";
}
return strEncode;
}
std::string CBase64::Decode(const char* Data, int DataByte, int& OutByte)
{
//解码表
const char DecodeTable[] =
{
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
62, // '+'
0, 0, 0,
63, // '/'
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // '0'-'9'
0, 0, 0, 0, 0, 0, 0,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 'A'-'Z'
0, 0, 0, 0, 0, 0,
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // 'a'-'z'
颗粒冷却塔};
//返回值
string strDecode;
int nValue;
int i = 0;
while (i < DataByte)防盗螺母
{
if (*Data != '\r' && *Data != '\n')
{
nValue = DecodeTable[*Data++] << 18;
nValue += DecodeTable[*Data++] << 12;
strDecode += (nValue & 0x00FF0000) >> 16;
OutByte++;
if (*Data != '=')
{
nValue += DecodeTable[*Data++] << 6;
strDecode += (nValue & 0x0000FF00) >> 8;
OutByte++;
if (*Data != '=')
{
nValue += DecodeTable[*Data++];
strDecode += nValue & 0x000000FF;
OutByte++;
}
}
i += 4;
}
else// 回车换⾏，跳过
{
Data++;
i++;
}
热风锅炉
}
return strDecode;
}
main.cpp
#include "Base64.h"
#include <tchar.h>
#include <windows.h>
#include <iostream>
using namespace std;
//以下是读写图⽚的调⽤代码：
bool ReadPhotoFile(std::basic_string<TCHAR> strFileName, std::string &strData)
{
HANDLE hFile;
hFile = CreateFile(strFileName.c_str(), GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); if (hFile == INVALID_HANDLE_VALUE)
{
return false;
}
DWORD dFileSize = GetFileSize(hFile, NULL);
char * pBuffer = new char[dFileSize + 1];
if (pBuffer == NULL)
return false;
memset(pBuffer, 0, dFileSize);
DWORD dReadSize(0);
if (!ReadFile(hFile, pBuffer, dFileSize, &dReadSize, NULL))
{
delete[]pBuffer;
CloseHandle(hFile);
return false;
}
CBase64 base64;
strData = "";
strData = base64.Encode((const char*)pBuffer, dReadSize);
delete[]pBuffer;
CloseHandle(hFile);
return true;
}
bool WritePhotoFile(std::basic_string<TCHAR> strFileName, std::string &strData)
{
交通事故现场图HANDLE hFile;
hFile = CreateFile(strFileName.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); if (hFile == INVALID_HANDLE_VALUE)
{
return false;
}
CBase64 base64;
int datalen(0);
DWORD dwritelen(0);
std::string strdcode = base64.Decode(strData.data(), strData.size(), datalen);
if (!WriteFile(hFile, strdcode.data(), datalen, &dwritelen, NULL))
{
CloseHandle(hFile);
return false;
}
CloseHandle(hFile);
return true;
}int main()
{
wstring path = L"C:\\Users\\Administrator\\Desktop\\test.jpg";
string data;
ReadPhotoFile(path, data);
wstring strfilename = L"C:\\Users\\Administrator\\Desktop\\123.jpg";
WritePhotoFile(strfilename, data);
for (int i = 0; i < 10;i++)
{
for (int j = 0; j < 5;j++)
{
if (j == 3)
{塑料冷却管
break;
}
cout << "j=" << j << endl;
}
cout << "i=" << i << endl;
}
return0;
}
