转载:http://blog.csdn.net/ljd_1986413/article/details/7940938
服务器程序和客户端程序应当分别运行在两台计算机上。
在运行服务器端的计算机终端执行:./file_server
在运行客户端的计算终端上执行:./file_client ipaddr_server
然后根据提示输入要传输的服务器上的文件,该文件必须在服务器的当前运行目录中,否则会提示找不到文件。
直接上源码吧:
[cpp] view plaincopy
- // file_server.c -- socket文件传输服务器端示例代码
- // /
- #include<netinet/in.h>
- #include<sys/types.h>
- #include<sys/socket.h>
- #include<stdio.h>
- #include<stdlib.h>
- #include<string.h>
- #define HELLO_WORLD_SERVER_PORT 6666
- #define LENGTH_OF_LISTEN_QUEUE 20
- #define BUFFER_SIZE 1024
- #define FILE_NAME_MAX_SIZE 512
- int main(int argc, char **argv)
- {
- // set socket's address information
- // 设置一个socket地址结构server_addr,代表服务器internet的地址和端口
- struct sockaddr_in server_addr;
- bzero(&server_addr, sizeof(server_addr));
- server_addr.sin_family = AF_INET;
- server_addr.sin_addr.s_addr = htons(INADDR_ANY);
- server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
- // create a stream socket
- // 创建用于internet的流协议(TCP)socket,用server_socket代表服务器向客户端提供服务的接口
- int server_socket = socket(PF_INET, SOCK_STREAM, 0);
- if (server_socket < 0)
- {
- printf("Create Socket Failed!\n");
- exit(1);
- }
- // 把socket和socket地址结构绑定
- if (bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr)))
- {
- printf("Server Bind Port: %d Failed!\n", HELLO_WORLD_SERVER_PORT);
- exit(1);
- }
- // server_socket用于监听
- if (listen(server_socket, LENGTH_OF_LISTEN_QUEUE))
- {
- printf("Server Listen Failed!\n");
- exit(1);
- }
- // 服务器端一直运行用以持续为客户端提供服务
- while(1)
- {
- // 定义客户端的socket地址结构client_addr,当收到来自客户端的请求后,调用accept
- // 接受此请求,同时将client端的地址和端口等信息写入client_addr中
- struct sockaddr_in client_addr;
- socklen_t length = sizeof(client_addr);
- // 接受一个从client端到达server端的连接请求,将客户端的信息保存在client_addr中
- // 如果没有连接请求,则一直等待直到有连接请求为止,这是accept函数的特性,可以
- // 用select()来实现超时检测
- // accpet返回一个新的socket,这个socket用来与此次连接到server的client进行通信
- // 这里的new_server_socket代表了这个通信通道
- int new_server_socket = accept(server_socket, (struct sockaddr*)&client_addr, &length);
- if (new_server_socket < 0)
- {
- printf("Server Accept Failed!\n");
- break;
- }
- char buffer[BUFFER_SIZE];
- bzero(buffer, sizeof(buffer));
- length = recv(new_server_socket, buffer, BUFFER_SIZE, 0);
- if (length < 0)
- {
- printf("Server Recieve Data Failed!\n");
- break;
- }
- char file_name[FILE_NAME_MAX_SIZE + 1];
- bzero(file_name, sizeof(file_name));
- strncpy(file_name, buffer,
- strlen(buffer) > FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE : strlen(buffer));
- FILE *fp = fopen(file_name, "r");
- if (fp == NULL)
- {
- printf("File:\t%s Not Found!\n", file_name);
- }
- else
- {
- bzero(buffer, BUFFER_SIZE);
- int file_block_length = 0;
- while( (file_block_length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)
- {
- printf("file_block_length = %d\n", file_block_length);
- // 发送buffer中的字符串到new_server_socket,实际上就是发送给客户端
- if (send(new_server_socket, buffer, file_block_length, 0) < 0)
- {
- printf("Send File:\t%s Failed!\n", file_name);
- break;
- }
- bzero(buffer, sizeof(buffer));
- }
- fclose(fp);
- printf("File:\t%s Transfer Finished!\n", file_name);
- }
- close(new_server_socket);
- }
- close(server_socket);
- return 0;
- }
[cpp] view plain copy
- // file_server.c -- socket文件传输服务器端示例代码
- // /
- #include<netinet/in.h>
- #include<sys/types.h>
- #include<sys/socket.h>
- #include<stdio.h>
- #include<stdlib.h>
- #include<string.h>
- #define HELLO_WORLD_SERVER_PORT 6666
- #define LENGTH_OF_LISTEN_QUEUE 20
- #define BUFFER_SIZE 1024
- #define FILE_NAME_MAX_SIZE 512
- int main(int argc, char **argv)
- {
- // set socket's address information
- // 设置一个socket地址结构server_addr,代表服务器internet的地址和端口
- struct sockaddr_in server_addr;
- bzero(&server_addr, sizeof(server_addr));
- server_addr.sin_family = AF_INET;
- server_addr.sin_addr.s_addr = htons(INADDR_ANY);
- server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
- // create a stream socket
- // 创建用于internet的流协议(TCP)socket,用server_socket代表服务器向客户端提供服务的接口
- int server_socket = socket(PF_INET, SOCK_STREAM, 0);
- if (server_socket < 0)
- {
- printf("Create Socket Failed!\n");
- exit(1);
- }
- // 把socket和socket地址结构绑定
- if (bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr)))
- {
- printf("Server Bind Port: %d Failed!\n", HELLO_WORLD_SERVER_PORT);
- exit(1);
- }
- // server_socket用于监听
- if (listen(server_socket, LENGTH_OF_LISTEN_QUEUE))
- {
- printf("Server Listen Failed!\n");
- exit(1);
- }
- // 服务器端一直运行用以持续为客户端提供服务
- while(1)
- {
- // 定义客户端的socket地址结构client_addr,当收到来自客户端的请求后,调用accept
- // 接受此请求,同时将client端的地址和端口等信息写入client_addr中
- struct sockaddr_in client_addr;
- socklen_t length = sizeof(client_addr);
- // 接受一个从client端到达server端的连接请求,将客户端的信息保存在client_addr中
- // 如果没有连接请求,则一直等待直到有连接请求为止,这是accept函数的特性,可以
- // 用select()来实现超时检测
- // accpet返回一个新的socket,这个socket用来与此次连接到server的client进行通信
- // 这里的new_server_socket代表了这个通信通道
- int new_server_socket = accept(server_socket, (struct sockaddr*)&client_addr, &length);
- if (new_server_socket < 0)
- {
- printf("Server Accept Failed!\n");
- break;
- }
- char buffer[BUFFER_SIZE];
- bzero(buffer, sizeof(buffer));
- length = recv(new_server_socket, buffer, BUFFER_SIZE, 0);
- if (length < 0)
- {
- printf("Server Recieve Data Failed!\n");
- break;
- }
- char file_name[FILE_NAME_MAX_SIZE + 1];
- bzero(file_name, sizeof(file_name));
- strncpy(file_name, buffer,
- strlen(buffer) > FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE : strlen(buffer));
- FILE *fp = fopen(file_name, "r");
- if (fp == NULL)
- {
- printf("File:\t%s Not Found!\n", file_name);
- }
- else
- {
- bzero(buffer, BUFFER_SIZE);
- int file_block_length = 0;
- while( (file_block_length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)
- {
- printf("file_block_length = %d\n", file_block_length);
- // 发送buffer中的字符串到new_server_socket,实际上就是发送给客户端
- if (send(new_server_socket, buffer, file_block_length, 0) < 0)
- {
- printf("Send File:\t%s Failed!\n", file_name);
- break;
- }
- bzero(buffer, sizeof(buffer));
- }
- fclose(fp);
- printf("File:\t%s Transfer Finished!\n", file_name);
- }
- close(new_server_socket);
- }
- close(server_socket);
- return 0;
- }
[cpp] view plaincopyprint?
- //
- // file_client.c socket传输文件的client端示例程序
- // ///
- #include<netinet/in.h> // for sockaddr_in
- #include<sys/types.h> // for socket
- #include<sys/socket.h> // for socket
- #include<stdio.h> // for printf
- #include<stdlib.h> // for exit
- #include<string.h> // for bzero
- #define HELLO_WORLD_SERVER_PORT 6666
- #define BUFFER_SIZE 1024
- #define FILE_NAME_MAX_SIZE 512
- int main(int argc, char **argv)
- {
- if (argc != 2)
- {
- printf("Usage: ./%s ServerIPAddress\n", argv[0]);
- exit(1);
- }
- // 设置一个socket地址结构client_addr, 代表客户机的internet地址和端口
- struct sockaddr_in client_addr;
- bzero(&client_addr, sizeof(client_addr));
- client_addr.sin_family = AF_INET; // internet协议族
- client_addr.sin_addr.s_addr = htons(INADDR_ANY); // INADDR_ANY表示自动获取本机地址
- client_addr.sin_port = htons(0); // auto allocated, 让系统自动分配一个空闲端口
- // 创建用于internet的流协议(TCP)类型socket,用client_socket代表客户端socket
- int client_socket = socket(AF_INET, SOCK_STREAM, 0);
- if (client_socket < 0)
- {
- printf("Create Socket Failed!\n");
- exit(1);
- }
- // 把客户端的socket和客户端的socket地址结构绑定
- if (bind(client_socket, (struct sockaddr*)&client_addr, sizeof(client_addr)))
- {
- printf("Client Bind Port Failed!\n");
- exit(1);
- }
- // 设置一个socket地址结构server_addr,代表服务器的internet地址和端口
- struct sockaddr_in server_addr;
- bzero(&server_addr, sizeof(server_addr));
- server_addr.sin_family = AF_INET;
- // 服务器的IP地址来自程序的参数
- if (inet_aton(argv[1], &server_addr.sin_addr) == 0)
- {
- printf("Server IP Address Error!\n");
- exit(1);
- }
- server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
- socklen_t server_addr_length = sizeof(server_addr);
- // 向服务器发起连接请求,连接成功后client_socket代表客户端和服务器端的一个socket连接
- if (connect(client_socket, (struct sockaddr*)&server_addr, server_addr_length) < 0)
- {
- printf("Can Not Connect To %s!\n", argv[1]);
- exit(1);
- }
- char file_name[FILE_NAME_MAX_SIZE + 1];
- bzero(file_name, sizeof(file_name));
- printf("Please Input File Name On Server.\t");
- scanf("%s", file_name);
- char buffer[BUFFER_SIZE];
- bzero(buffer, sizeof(buffer));
- strncpy(buffer, file_name, strlen(file_name) > BUFFER_SIZE ? BUFFER_SIZE : strlen(file_name));
- // 向服务器发送buffer中的数据,此时buffer中存放的是客户端需要接收的文件的名字
- send(client_socket, buffer, BUFFER_SIZE, 0);
- FILE *fp = fopen(file_name, "w");
- if (fp == NULL)
- {
- printf("File:\t%s Can Not Open To Write!\n", file_name);
- exit(1);
- }
- // 从服务器端接收数据到buffer中
- bzero(buffer, sizeof(buffer));
- int length = 0;
- while(length = recv(client_socket, buffer, BUFFER_SIZE, 0))
- {
- if (length < 0)
- {
- printf("Recieve Data From Server %s Failed!\n", argv[1]);
- break;
- }
- int write_length = fwrite(buffer, sizeof(char), length, fp);
- if (write_length < length)
- {
- printf("File:\t%s Write Failed!\n", file_name);
- break;
- }
- bzero(buffer, BUFFER_SIZE);
- }
- printf("Recieve File:\t %s From Server[%s] Finished!\n", file_name, argv[1]);
- // 传输完毕,关闭socket
- fclose(fp);
- close(client_socket);
- return 0;
- }
客户端不一定要bind(),服务端一定要bind(),为什么?不然客户端怎么知道服务器位置(IP+PORT)。 一般客户端不绑定端口,因为客户程序经常开关, 由于一些原因(这里我说不清楚,你碰到了自然理解), 断开时端口很少立刻释放(一般要1、2分钟)。 所以客户端绑定端口容易出问题。
注:服务器绑定的是侦听端口,客户连接后, 新分配一个sock和它连接(这个sock的port是不同的,相当于没有bind的一个端口) 由于侦听端口是没有实际联接的,所以断开时不需握手,也就没有释放问题了。 (注这段是回答时突然想到的,自我感觉是正确的,大家来批判啊)