Question

采用tcp协议,使用socket编程,编写程序完成客户端发送消息给服务端,服务端接到消息后，再发

给客户端

Answer 1

服务端代码：
/*server.c*/

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <netinet/in.h>

#define PORT 4321
#define BUFFER_SIZE 1024
#define MAX_QUE_CONN_NM 5

int main()
{
struct sockaddr_in server_sockaddr, client_sockaddr;
int sin_size, recvbytes;
int sockfd, client_fd;
char buf[BUFFER_SIZE];

/*建立socket连接*/
if ((sockfd = socket(AF_INET,SOCK_STREAM,0))== -1)
{
perror("socket");
exit(1);
}
printf("Socket id = %d\n",sockfd);

/*设置sockaddr_in 结构体中相关参数*/
server_sockaddr.sin_family = AF_INET;
server_sockaddr.sin_port = htons(PORT);
server_sockaddr.sin_addr.s_addr = INADDR_ANY;
bzero(&(server_sockaddr.sin_zero), 8);

int i = 1;/* 使得重复使用本地地址与套接字进行绑定 */
setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));

/*绑定函数bind*/
if (bind(sockfd, (struct sockaddr *)&server_sockaddr, sizeof(struct sockaddr))== -1)
{
perror("bind");
exit(1);
}
printf("Bind success!\n");

/*调用listen函数*/
if (listen(sockfd, MAX_QUE_CONN_NM) == -1)
{
perror("listen");
exit(1);
}
printf("Listening....\n");

/*调用accept函数，等待客户端的连接*/
if ((client_fd = accept(sockfd, (struct sockaddr *)&client_sockaddr, &sin_size)) == -1)
{
perror("accept");
exit(1);
}

/*调用recv函数接收客户端的请求*/
memset(buf , 0, sizeof(buf));
if ((recvbytes = recv(client_fd, buf, BUFFER_SIZE, 0)) == -1)
{
perror("recv");
exit(1);
}
printf("Received a message: %s\n", buf);

if ((sendbytes = send(sockfd, buf, strlen(buf), 0)) == -1)
{
perror("send");
exit(1);
}
close(sockfd);
exit(0);
}

客户端：
/*client.c*/

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/in.h>

#define PORT 4321
#define BUFFER_SIZE 1024

int main(int argc, char *argv[])
{
int sockfd, sendbytes;
char buf[BUFFER_SIZE];
struct hostent *host;
struct sockaddr_in serv_addr;

if(argc < 3)
{
fprintf(stderr,"USAGE: ./client Hostname(or ip address) Text\n");
exit(1);
}

/*地址解析函数*/
if ((host = gethostbyname(argv[1])) == NULL)
{
perror("gethostbyname");
exit(1);
}

memset(buf, 0, sizeof(buf));
sprintf(buf, "%s", argv[2]);

/*创建socket*/
if ((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1)
{
perror("socket");
exit(1);
}

/*设置sockaddr_in 结构体中相关参数*/
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(PORT);
serv_addr.sin_addr = *((struct in_addr *)host->h_addr);
bzero(&(serv_addr.sin_zero), 8);

/*调用connect函数主动发起对服务器端的连接*/
if(connect(sockfd,(struct sockaddr *)&serv_addr, sizeof(struct sockaddr))== -1)
{
perror("connect");
exit(1);
}

/*发送消息给服务器端*/
if ((sendbytes = send(sockfd, buf, strlen(buf), 0)) == -1)
{
perror("send");
exit(1);
}

if ((recvbytes = recv(sockfd, buf, BUFFER_SIZE, 0)) == -1)
{
perror("recv");
exit(1);
}

close(sockfd);
exit(0);
}

追问

这个c的我想求java的

追答

请看博客
http://www.jb51.net/article/45024.htm