阻塞式socket例子学习

/************************************************************************* 
> File Name: Win_Server.c 
> Author: SongLee 
 ************************************************************************/

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <WinSock2.h> 

#define PORT 8087 
#define SERVER_IP "127.0.0.1" 
#define BUFFER_SIZE 1024 
#define FILE_NAME_MAX_SIZE 512 
#pragma comment(lib, "WS2_32") 

int main() 
{ 
    // 声明并初始化一个服务端(本地)的地址结构 
    sockaddr_in server_addr; 
    server_addr.sin_family = AF_INET; 
    server_addr.sin_addr.S_un.S_addr = INADDR_ANY; 
    server_addr.sin_port = htons(PORT); 

    // 初始化socket dll 
    WSADATA wsaData; 
    WORD socketVersion = MAKEWORD(2, 0); 
    if(WSAStartup(socketVersion, &wsaData) != 0) 
    { 
        printf("Init socket dll error!"); 
        exit(1); 
    } 

    // 创建socket 
    SOCKET m_Socket = socket(AF_INET, SOCK_STREAM, 0); 
    if (SOCKET_ERROR == m_Socket) 
    { 
        printf("Create Socket Error!"); 
        exit(1); 
    } 

    //绑定socket和服务端(本地)地址 
    if (SOCKET_ERROR == bind(m_Socket, (LPSOCKADDR)&server_addr, sizeof(server_addr))) 
    { 
        printf("Server Bind Failed: %d", WSAGetLastError()); 
        exit(1); 
    } 

    //监听 
    if (SOCKET_ERROR == listen(m_Socket, 10)) //m_Socket监听套接字，专门负责客户端的监听
    { 
        printf("Server Listen Failed: %d", WSAGetLastError()); 
        exit(1); 
    } 


    while(1) 
    { 
        printf("Listening To Client...\n"); 

        sockaddr_in client_addr; 
        int client_addr_len = sizeof(client_addr); 

        SOCKET m_New_Socket = accept(m_Socket, (sockaddr *)&client_addr, &client_addr_len); //m_New_Socket创建的与客户端通信的socket，后面与客户端通信就依靠这个套接字
        if (SOCKET_ERROR == m_New_Socket) 
        { 
            printf("Server Accept Failed: %d", WSAGetLastError()); 
            break; 
        } 

        char buffer[BUFFER_SIZE]; 
        memset(buffer, 0, BUFFER_SIZE); 
        if (recv(m_New_Socket, buffer, BUFFER_SIZE, 0) < 0) //接收数据是从m_New_Socket
        { 
            printf("Server Receive Data Failed!"); 
            break; 
        } 

        char file_name[FILE_NAME_MAX_SIZE+1]; 
        memset(file_name, 0, FILE_NAME_MAX_SIZE+1); 
        strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE:strlen(buffer)); 
        printf("%s\n", file_name); 

        FILE * fp = fopen(file_name, "rb"); //windows下是"rb",表示打开一个只读的二进制文件 
        if (NULL == fp) 
        { 
            printf("File: %s Not Found\n", file_name); 
        } 
        else
        { 
            memset(buffer, 0, BUFFER_SIZE); 
            int length = 0; 

            while ((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0) 
            { 
                if (send(m_New_Socket, buffer, length, 0) < 0) 
                { 
                    printf("Send File: %s Failed\n", file_name); 
                    break; 
                } 
                memset(buffer, 0, BUFFER_SIZE); 
            } 

            fclose(fp); 
            printf("File: %s Transfer Successful!\n", file_name); 
        } 
        closesocket(m_New_Socket); 
    } 

    closesocket(m_Socket); 
    //释放winsock库 
    WSACleanup(); 
    return 0; 
} 

client

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <WinSock2.h> 

#define PORT 8087 
#define SERVER_IP "127.0.0.1" 
#define BUFFER_SIZE 1024 
#define FILE_NAME_MAX_SIZE 512 
#pragma comment(lib, "WS2_32") 
int main()
{
    //初始化socket dll
    WSADATA wsaData;
    WORD socketVersion = MAKEWORD(2, 0);
    if (WSAStartup(socketVersion, &wsaData) != 0)
    {
        printf("Init socket dll error!"); 
        exit(1); 
    }

    //创建socket
    SOCKET c_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (SOCKET_ERROR == c_socket)
    {
        printf("Create Socket Error!"); 
        system("pause"); 
        exit(1); 
    }

    //指定服务器地址
    sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.S_un.S_addr = inet_addr(SERVER_IP);
    server_addr.sin_port = htons(PORT);

    if (SOCKET_ERROR == connect(c_socket, (LPSOCKADDR)&server_addr, sizeof server_addr))//此时系统为c_socket分配一个尚未使用的本地端口
    {
        printf("Can Not Connect To Server IP!\n"); 
        system("pause"); 
        exit(1); 
    }

    //输入文件名
    char file_name[FILE_NAME_MAX_SIZE+1] = {0}; 
    printf("Please Input File Name On Server: "); 
    scanf("%s", &file_name); 

    char buffer[BUFFER_SIZE]; 
    memset(buffer, 0, BUFFER_SIZE); 
    strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE ? BUFFER_SIZE:strlen(file_name)); 

    //向服务器发送文件名
    if (send(c_socket, buffer, BUFFER_SIZE, 0) < 0)
    {
        printf("Send File Name Failed\n"); 
        system("pause"); 
        exit(1); 
    }

    FILE* fp = fopen(file_name, "wb");
    if (NULL == fp)
    {
        printf("File: %s Can Not Open To Write\n", file_name); 
        system("pause"); 
        exit(1); 
    }
    else{
        memset(buffer, 0, BUFFER_SIZE); 
        int length = 0; 
        while ((length = recv(c_socket, buffer, BUFFER_SIZE, 0)) > 0)
        {
            if (fwrite(buffer, sizeof(char), length, fp) < length) 
            { 
                printf("File: %s Write Failed\n", file_name); 
                break; 
            } 
            memset(buffer, 0, BUFFER_SIZE); 
        }
        printf("Receive File: %s From Server Successful!\n", file_name); 
    }
    fclose(fp); 
    closesocket(c_socket); 

    //释放winsock库 
    WSACleanup(); 

    system("pause"); 
    return 0; 
}