c++网络编程：实现简单的聊天——基于服务器/客户端的模式

c++ socket编程 服务器/客户端

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实现: 客户端往服务器端发送一条数据,服务器端接收数据并也发送一条数据给客户端。

废话少说 直接上代码

[文字描述都写在注释]

服务器实现

#include "stdafx.h"
#include <iostream>  
#include "windows.h" //一定要包含该头文件
using namespace std;
#pragma comment(lib, "WS2_32.lib")  //显示加载 ws2_32.dll ws2_32.dll就是最新socket版本

int main()
{
  cout << "-----------服务器-----------" << endl;

  //套接字初始化
  WSADATA wsaData;  //这个结构被用来存储被WSAStartup函数调用后返回的 Windows Sockets 数据。
  WORD sockVersion = MAKEWORD(2, 2);  //windows网络编程库的版本号信息
  if (WSAStartup(sockVersion, &wsaData) != 0) //WSAStartup函数是在程序中初始化并加载Windows网络
  {
    cout << "套接字初始化失败!" << endl;
    return 0;
  }

  //创建服务器套接字
  SOCKET SeverSocket;
  if ((SeverSocket = socket(AF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR)
  {
    cout << "套接字创建失败！" << endl;
    return 0;
  }
  struct sockaddr_in SeverAddress;    //一个绑定地址:有IP地址,有端口号,有协议族
  memset(&SeverAddress, 0, sizeof(sockaddr_in)); //初始化结构体
  SeverAddress.sin_family = AF_INET;
  SeverAddress.sin_addr.S_un.S_addr = htonl(INADDR_ANY);//填入本机IP地址 
  SeverAddress.sin_port = htons(60000);//设定端口号

  //绑定套接字     指定绑定的IP地址和端口号
  if (bind(SeverSocket, (sockaddr*)&SeverAddress, sizeof(SeverAddress)) == SOCKET_ERROR)
  {
    cout << "套接字绑定失败！"<<endl;
    return 0;
  }

  //服务器监听 
  if (listen(SeverSocket, SOMAXCONN) == SOCKET_ERROR) //监听的第二个参数就是:能存放多少个客户端请求,到并发编程的时候很有用
  {
    cout << "监听失败！"<<endl;
    return 0;
  }
  else
    cout << "服务器正在监听："<<endl;

  //服务器接受连接请求
  sockaddr_in revClientAddress; //套接字的地址，端口
  SOCKET revClientSocket = INVALID_SOCKET;    //用来接收客户端连接
  //memset(&revClientAddress, 0, sizeof(revClientAddress));
  int addlen = sizeof(revClientAddress);
  if ((revClientSocket = accept(SeverSocket, (sockaddr*)&revClientAddress, &addlen)) == INVALID_SOCKET)
  {
    cout << "接受客户端连接失败！" << endl;
    return 0;
  }
  else
    cout << "接受客户端连接成功！"<<endl;

  //服务器接受数据
  char recvbuf[2048] = {};
  if ( recv(revClientSocket, recvbuf, 2048, 0) == SOCKET_ERROR)
  {
    cout << "数据接受失败！" <<WSAGetLastError()<< endl;
    return 0;
  }
  else
    cout << "服务器接收的数据：" << recvbuf << endl;

  //服务器发送数据
  char sendbuf[2048] = "from server:hello client.";
  if (send(revClientSocket, sendbuf, strlen(sendbuf), 0) == SOCKET_ERROR)
  {
    cout << "发送消息失败！";
  }
  //关闭socket
  closesocket(revClientSocket);
  closesocket(SeverSocket);

  //终止
  WSACleanup();
  cout << "服务器停止！" << endl;
  return 0;
}

客户端实现

在这里再提醒一点,运行程序的时候,我们是先运行服务端程序,再运行客户端程序.

所以有些同学可能会说"我们的代码都一样啊!怎么到我这就不成功了呢?",这是一个

低级的错误,我们要避免。

#include "stdafx.h"
#include "windows.h"
#include "iostream"
using namespace std;
#pragma comment(lib, "ws2_32.lib")


int main()
{
    cout << "-----------客户端-----------" << endl;
    WSADATA  wsa;
    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
    {
        cout << "套接字初始化失败!"<<endl;
    }
    SOCKET clientSocket;
    if ((clientSocket = socket(AF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR)
    {
        cout << "套接字创建失败!"<<endl;
    }
    struct sockaddr_in SeverAddress;        //服务器地址 也就是即将要连接的目标地址
    memset(&SeverAddress, 0, sizeof(sockaddr_in)); 
    SeverAddress.sin_family = AF_INET;
    SeverAddress.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");  //127.0.0.1表示本机ip地址
    SeverAddress.sin_port = htons(60000);//设定端口号

    //开始连接
    if (connect(clientSocket, (sockaddr*)&SeverAddress, sizeof(SeverAddress)) == SOCKET_ERROR)
    {
        cout << "客户端：和服务器连接失败！"<<endl;
        return 0;
    }
    else
        cout << "客户端：与服务器连接成功！" << endl;

    //客户端发送数据给服务器
    char sendbuf[2048] = "from client:hello server.";
    if (send(clientSocket, sendbuf, strlen(sendbuf), 0) == SOCKET_ERROR)
    {
        cout << "发送消息失败！";
    }

    //客户端接受来自服务器的数据
    char  recvbuf[2048] = {};
    if (recv(clientSocket, recvbuf, 2048, 0) == SOCKET_ERROR)
    {
        cout << "数据接受失败" << endl;
    }
    else
        cout << "客户端接收的数据:" << recvbuf << endl;

    //  关闭socket
    if (clientSocket != INVALID_SOCKET) {
        closesocket(clientSocket);
        clientSocket = INVALID_SOCKET;
    }

    //  终止
    WSACleanup();
    cout << "客户端退出！" << endl;
    return 0;
}

运行结果如下

现在来实现较为自由的聊天

上面代码只是将缓冲区的数据发送出去，可以改为把从键盘输入的数据发送出去，即实现更”自由“的聊天。先来看第一种实现的方法。

代码主体部分不变，在数据传输部分加一个while循环即可。

服务器

while (1)
  {
    //服务器接受数据
    char recvbuf[2048] = {};    //接收缓冲区
    if (recv(revClientSocket, recvbuf, 2048, 0) == SOCKET_ERROR)
    {
      cout << "数据接受失败！" << WSAGetLastError() << endl;
      return 0;
    }
    else
      cout << "服务器接收的数据：" << recvbuf << endl;

    //服务器发送数据
    char sendbuf[2048] = {};    //发送缓冲区
    cin.getline(sendbuf, 2048);
    if (send(revClientSocket, sendbuf, strlen(sendbuf), 0) == SOCKET_ERROR)
    {
      cout << "发送消息失败！";
    }
  }

客户端

while (1)
  {
    //客户端发送数据给服务器
    char sendbuf[2048] = {};    //发送缓冲区
    cin.getline(sendbuf, 2048);
    if (send(clientSocket, sendbuf,strlen(sendbuf), 0) == SOCKET_ERROR)
    {
      cout << "发送消息失败！";
    }

    //客户端接受来自服务器的数据
    char  recvbuf[2048] = {};   //接收缓冲区
    if (recv(clientSocket, recvbuf, 2048, 0) == SOCKET_ERROR)
    {
      cout << "数据接受失败" << endl;
    }
    else
      cout << "客户端接收的数据:" << recvbuf << endl;
  }

效果图

但是这样存在问题，由于while循环中，接收和发送总是按顺序进行，无法同时进行，因此只能轮流说话，一人说一句。从客户端开始。究其原因是因为send()、recv()是拥塞函数！

实现自由聊天

针对上面的问题进一步做出改进，为了程序能够同时进行接受和发送，使用多线程。

服务器

#include "stdafx.h"
#include <iostream>  
#include "windows.h" //一定要包含该头文件
#include "process.h"
#include <string>
using namespace std;
#pragma comment(lib, "WS2_32.lib")  //显示加载 ws2_32.dll ws2_32.dll就是最新socket版本

void Receive(void *param)   //接受数据的线程函数
{
  while (1)
  {
    //服务器接受数据
    SOCKET revClientSocket = *(SOCKET*)(param);
    char recvbuf[2048] = {};    //接收缓冲区
    if (recv(revClientSocket, recvbuf, 2048, 0) == SOCKET_ERROR)
    {
      cout << "数据接受失败！" << endl;
    }
    else
      cout << "【客户端】说：" << recvbuf << endl;
  }
}

void Send(void *param)    //发送数据的线程函数
{
  while (1)
  {
    //服务器发送数据
    SOCKET revClientSocket = *(SOCKET*)(param);
    char sendbuf[2048] = {};    //发送缓冲区
    cin.getline(sendbuf, 2048);
    if (send(revClientSocket, sendbuf, strlen(sendbuf), 0) == SOCKET_ERROR)
    {
      cout << "发送消息失败！" << endl;
    }
    else
      cout << "【自己】说：" << sendbuf << endl;
  }
}

int main()
{
  cout << "-----------服务器-----------" << endl;

  //套接字初始化
  WSADATA wsaData;  //这个结构被用来存储被WSAStartup函数调用后返回的 Windows Sockets 数据。
  WORD sockVersion = MAKEWORD(2, 2);  //windows网络编程库的版本号信息
  if (WSAStartup(sockVersion, &wsaData) != 0) //WSAStartup函数是在程序中初始化并加载Windows网络
  {
    cout << "套接字初始化失败!" << endl;
    return 0;
  }

  //创建服务器套接字
  SOCKET SeverSocket;
  if ((SeverSocket = socket(AF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR)
  {
    cout << "套接字创建失败！" << endl;
    return 0;
  }
  struct sockaddr_in SeverAddress;    //一个绑定地址:有IP地址,有端口号,有协议族
  memset(&SeverAddress, 0, sizeof(sockaddr_in)); //初始化结构体
  SeverAddress.sin_family = AF_INET;
  SeverAddress.sin_addr.S_un.S_addr = htonl(INADDR_ANY);//填入本机IP地址 
  SeverAddress.sin_port = htons(60000);//设定端口号

  //绑定套接字     指定绑定的IP地址和端口号
  if (bind(SeverSocket, (sockaddr*)&SeverAddress, sizeof(SeverAddress)) == SOCKET_ERROR)
  {
    cout << "套接字绑定失败！"<<endl;
    return 0;
  }

  //服务器监听 
  if (listen(SeverSocket, SOMAXCONN) == SOCKET_ERROR) //监听的第二个参数就是:能存放多少个客户端请求,到并发编程的时候很有用
  {
    cout << "监听失败！"<<endl;
    return 0;
  }
  else
    cout << "服务器正在监听："<<endl;

  //服务器接受连接请求
  sockaddr_in revClientAddress; //套接字的地址，端口
  SOCKET revClientSocket = INVALID_SOCKET;    //用来接收客户端连接
  //memset(&revClientAddress, 0, sizeof(revClientAddress));
  int addlen = sizeof(revClientAddress);
  if ((revClientSocket = accept(SeverSocket, (sockaddr*)&revClientAddress, &addlen)) == INVALID_SOCKET)
  {
    cout << "接受客户端连接失败！" << endl;
    return 0;
  }
  else
    cout << "接受客户端连接成功！"<<endl;

  //创建两个子线程
  _beginthread(Receive, 0, &revClientSocket);
  _beginthread(Send, 0, &revClientSocket);

  while (1){}  //为了避免主线程退出使子线程被迫消亡，使主线程进入循环

  //关闭socket
  closesocket(revClientSocket);
  closesocket(SeverSocket);

  //终止
  WSACleanup();
  cout << "服务器停止！" << endl;
  return 0;
}

客户端

#include "stdafx.h"
#include "windows.h"
#include "iostream"
#include "process.h"
#include <string>
using namespace std;
#pragma comment(lib, "ws2_32.lib")

void Receive(void *param)
{
    while (1)
    {
        //客户端接受来自服务器的数据
        SOCKET clientSocket = *(SOCKET*)(param);
        char  recvbuf[2048] = {};       //接收缓冲区
        if (recv(clientSocket, recvbuf, 2048, 0) == SOCKET_ERROR)
        {
            cout << "数据接受失败" << endl;
        }
        else
            cout << "【服务器】说:" << recvbuf << endl;
    }
}

void Send(void *param)
{
    while (1)
    {
        //客户端发送数据给服务器
        SOCKET clientSocket = *(SOCKET*)(param);
        char sendbuf[2048] = {};        //发送缓冲区
        cin.getline(sendbuf, 2048);
        if (send(clientSocket, sendbuf, strlen(sendbuf), 0) == SOCKET_ERROR)
        {
            cout << "发送消息失败！";
        }
        else
            cout << "【自己】说：" << sendbuf << endl;
    }
}

int main()
{
    cout << "-----------客户端-----------" << endl;
    WSADATA  wsa;
    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
    {
        cout << "套接字初始化失败!"<<endl;
    }
    SOCKET clientSocket;
    if ((clientSocket = socket(AF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR)
    {
        cout << "套接字创建失败!"<<endl;
    }
    struct sockaddr_in SeverAddress;        //服务器地址 也就是即将要连接的目标地址
    memset(&SeverAddress, 0, sizeof(sockaddr_in)); 
    SeverAddress.sin_family = AF_INET;
    SeverAddress.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");  //127.0.0.1表示本机ip地址
    SeverAddress.sin_port = htons(60000);//设定端口号

    //开始连接
    if (connect(clientSocket, (sockaddr*)&SeverAddress, sizeof(SeverAddress)) == SOCKET_ERROR)
    {
        cout << "客户端：和服务器连接失败！"<<endl;
        return 0;
    }
    else
        cout << "与服务器连接成功！" << endl;

    //创建两个子线程
    _beginthread(Receive, 0, &clientSocket);
    _beginthread(Send, 0, &clientSocket);

    Sleep(INFINITE);    //这里采用另外一种技术避免主线程执行完退出——使其无限期休眠
    //  关闭socket
    if (clientSocket != INVALID_SOCKET) {
        closesocket(clientSocket);
        clientSocket = INVALID_SOCKET;
    }

    //  终止
    WSACleanup();
    cout << "客户端退出！" << endl;
    return 0;
}

运行效果