C++实现邮件发送程序在vs2013测试通过，一共3个文件，发邮件的程序封装为Csmtp 类。

1.测试用的主函数

//#include "Csmtp.h"#pragma comment(lib, "Kernel32.lib") int main(){ Csmtp mail( 25, "smtp.126.com", "username@126.com",// 来源邮箱 "pwd", "username@126.com" //目标邮箱 ); if (!mail.CReateSocket()) { cout << "ReateSocket failed!" << endl; return -1;// } mail.setTitle("test mail"); mail.setContent("this is content."); mail.addfile("test1.png"); //添加附件 mail.addfile("test2.png"); //添加附件 mail.SendMail(); //类主函数 return 0; }

2.Csmtp类定义

#include <iostream> #include <string> #include <vector>#include <fstream> #include <WinSock2.h> //适用平台 Windows#pragma comment(lib, "ws2_32.lib") // POP3服务器（端口：110） Csmtp服务器（端口：25） using namespace std;class Csmtp { int port; string domain; string user; string pass; string target; string title; //邮件标题 string content; //邮件内容 HOSTENT* pHostent; SOCKET sockClient; //客户端的套接字 vector <string> filename; //存储附件名的向量public: Csmtp( int _port, //端口25 string _domain, //域名 string _user, //发送者的邮箱 string _pass, //密码 string _target) //目标邮箱 :port(_port),domain(_domain),user(_user),pass(_pass), target(_target){};//内容 bool CReateSocket(); void setTitle(string tem){title = tem;} void setContent(string tem){content = tem;} int SendAttachment(SOCKET &sockClient); int SendMail(); void addfile(string str){filename.push_back(str);}};

3. Csmtp 类的实现

#include "Csmtp.h"//#include <afx.h>//异常类static const char base64Char[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; char* base64Encode(char const* origSigned, unsigned origLength) { unsigned char const* orig = (unsigned char const*)origSigned; // in case any input bytes have the MSB set if (orig == NULL) return NULL; unsigned const numOrig24BitValues = origLength / 3; bool havePadding = origLength > numOrig24BitValues * 3; bool havePadding2 = origLength == numOrig24BitValues * 3 + 2; unsigned const numResultBytes = 4 * (numOrig24BitValues + havePadding); char* result = new char[numResultBytes + 3]; // allow for trailing '/0' // Map each full group of 3 input bytes into 4 output base-64 characters: unsigned i; for (i = 0; i < numOrig24BitValues; ++i) { result[4 * i + 0] = base64Char[(orig[3 * i] >> 2) & 0x3F]; result[4 * i + 1] = base64Char[(((orig[3 * i] & 0x3) << 4) | (orig[3 * i + 1] >> 4)) & 0x3F]; result[4 * i + 2] = base64Char[((orig[3 * i + 1] << 2) | (orig[3 * i + 2] >> 6)) & 0x3F]; result[4 * i + 3] = base64Char[orig[3 * i + 2] & 0x3F]; } // Now, take padding into account. (Note: i == numOrig24BitValues) if (havePadding) { result[4 * i + 0] = base64Char[(orig[3 * i] >> 2) & 0x3F]; if (havePadding2) { result[4 * i + 1] = base64Char[(((orig[3 * i] & 0x3) << 4) | (orig[3 * i + 1] >> 4)) & 0x3F]; result[4 * i + 2] = base64Char[(orig[3 * i + 1] << 2) & 0x3F]; } else { result[4 * i + 1] = base64Char[((orig[3 * i] & 0x3) << 4) & 0x3F]; result[4 * i + 2] = '='; } result[4 * i + 3] = '='; } result[numResultBytes] = '\0'; return result; } int Csmtp::SendAttachment(SOCKET &sockClient) { for (std::vector<string>::iterator iter = filename.begin();iter != filename.end(); iter++) { cout << "Attachment is sending··· " << endl; string path=*iter; ifstream ifs(path, ios::in | ios::binary); //'或链接2个属性，以输入、二进制打开' if (false == ifs.is_open()) { cout<<"无法打开文件！"<<endl; return 1; } string sendstring; sendstring = "--@boundary@\r\nContent-Type: application/octet-stream; name=\"1.jpg\"\r\n"; sendstring += "Content-Disposition: attachment; filename=\"1.jpg\"\r\n"; sendstring += "Content-Transfer-Encoding: base64\r\n\r\n"; send(sockClient, sendstring.c_str(), sendstring.length(), 0); //infile.read((char*)buffer,sizeof(数据类型)); // get length of file: ifs.seekg (0, ifs.end); int length = ifs.tellg(); ifs.seekg (0, ifs.beg); cout<<"length:"<<length<<endl; // allocate memory: char * buffer = new char [length]; // read data as a block: ifs.read (buffer,length); ifs.close(); char *pbase; pbase = base64Encode(buffer, length); delete[]buffer; string str(pbase); delete[]pbase; str+="\r\n"; int err =send(sockClient, str.c_str(), strlen(str.c_str()), 0); if (err != strlen(str.c_str())) { cout << "文件传送出错!" << endl; return 1; } } return 0;} bool Csmtp::CReateSocket() { WSADATA wsaData; WORD wVersionRequested = MAKEWORD(2, 1); //WSAStarup，即WSA(Windows SocKNDs Asynchronous，Windows套接字异步)的启动命令 int err = WSAStartup(wVersionRequested, &wsaData); cout<<"WSAStartup(0:successful):"<<err<<endl; char namebuf[128]; //获得本地计算机名 string ip_list; if(0==gethostname(namebuf,128)) { struct hostent* pHost; //获得本地IP地址 pHost=gethostbyname(namebuf); //pHost返回的是指向主机的列表 for (int i=0;pHost!=NULL&&pHost->h_addr_list[i]!=NULL;i++) { string tem = inet_ntoa(*(struct in_addr *)pHost->h_addr_list[i]); ip_list += tem; ip_list += "\n"; } } else { cout<<"获取主机信息失败..."<<endl ; } ////////////////////////////////////////////////////////////////////////// title=namebuf;// 邮件标题 content=ip_list; //主机ip sockClient = socket(AF_INET, SOCK_STREAM, 0); //建立socket对象 pHostent = gethostbyname(domain.c_str()); //得到有关于域名的信息 if (pHostent == NULL) { printf( "创建连接失败，也许没联网！\n" ); return false; } return true;}int Csmtp::SendMail(){ char *ecode; char buff[500]; //recv函数返回的结果 int err = 0; string message; // SOCKADDR_IN addrServer; //服务端地址 addrServer.sin_addr.S_un.S_addr = *((DWORD *)pHostent->h_addr_list[0]); //得到smtp服务器的网络字节序的ip地址 addrServer.sin_family = AF_INET; addrServer.sin_port = htons(port); //连接端口25 //int connect (SOCKET s , const struct sockaddr FAR *name , int namelen ); err = connect(sockClient, (SOCKADDR*)&addrServer, sizeof(SOCKADDR)); //向服务器发送请求 cout<<"connect:"<<err<<endl; //telnet smtp.126.com 25 连接服务器结束 buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"connect:"<<buff<<endl; message="ehlo 126.com\r\n"; send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"helo:"<<buff<<endl; message="auth login \r\n"; send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"auth login:"<<buff<<endl; //上传邮箱名 message=user; ecode = base64Encode(message.c_str(), strlen(message.c_str())); message = ecode; message += "\r\n"; delete[]ecode; send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"usrname:"<<buff<<endl; //上传邮箱密码 message=pass; ecode = base64Encode(message.c_str(), strlen(message.c_str())); message = ecode; delete[]ecode; message += "\r\n"; send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"password:"<<buff<<endl; message="mail from:<"+user+">\r\nrcpt to:<"+target+">\r\n"; send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"mail from: "<<buff<<endl; buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"rcpt to: "<<buff<<endl; message="data\r\n";//data要单独发送一次 send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"data: "<<buff<<endl; ///-----------------------------------------DATA------------------------------------- //要使用Csmtp 发送附件, 需要对Csmtp 头信息进行说明, 改变Content-type 及为每一段正文添加BOUNDARY 名, cout<<"-------------------DATA------------------------"<<endl; // 头 message="from:"+user+"\r\nto:"+target+"\r\nsubject:"+title+"\r\n"; message += "MIME-Version: 1.0\r\n"; message += "Content-Type: multipart/mixed;boundary=@boundary@\r\n\r\n"; send(sockClient, message.c_str(), message.length(), 0); // 正文 message = "--@boundary@\r\nContent-Type: text/plain;charset=\"gb2312\"\r\n\r\n"+content+"\r\n\r\n"; send(sockClient, message.c_str(), message.length(), 0); //------------------------------------------------------------------------------------------------ // 发送附件 SendAttachment(sockClient); message = "--@boundary@--\r\n.\r\n"; send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; //cout<<"end_qwertyuiop:"<<buff<<endl; message="QUIT\r\n"; send(sockClient, message.c_str(), message.length(), 0); buff[recv(sockClient, buff, 500, 0)]='\0'; cout<<"Send mail is finish:"<<buff<<endl; return 0;}

容易理解的简化版可以点击->这里

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