Linux下实现客户端和服务器端的通信

安岽旭 發表於 2019-6-20 10:32:00

Linux下实现客户端和服务器端的通信

首先，可以将代码复制下来放到U盘里，然后挂载到Linux上
挂载步骤
找到设备->USB->你U盘的名字
<img src="https://img2018.cnblogs.com/blog/1490994/201906/1490994-20190620102156865-214395316.png">
 
挂载成功
<img src="https://img2018.cnblogs.com/blog/1490994/201906/1490994-20190620102251437-13453596.png">
访问U盘把代码拷贝到home文件夹下，就可以直接进行编译。
client.c 
<div class="cnblogs_code">
<pre> #include <stdio.h>
#include <unistd.h>
#include <strings.h>
#include<string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <netdb.h>

#define PORT 1234
#define MAXDATASIZE 100

char receiveM[100];
 char sendM[100];

int main(int argc, char *argv[])
{
int fd, numbytes;
struct hostent *he;
struct sockaddr_in server;

//检查用户输入，如果用户输入不正确，提示用户正确的输入方法
if (argc !=2) { printf("Usage: %s <IP Address>\n",argv[0]);
exit(1);
}

// 通过函数 gethostbyname()获得字符串形式的ip地址，并赋给he
if ((he=gethostbyname(argv[1]))==NULL){
printf("gethostbyname() error\n");
exit(1);
}

// 产生套接字fd
if ((fd=socket(AF_INET, SOCK_STREAM, 0))==-1){
printf("socket() error\n");
exit(1);
}

bzero(&server,sizeof(server));

server.sin_family = AF_INET;
server.sin_port = htons(PORT);
server.sin_addr = *((struct in_addr *)he->h_addr);
if(connect(fd, (struct sockaddr *)&server,sizeof(struct sockaddr))==-1){
printf("connect() error\n");
exit(1);
}

// 向服务器发送数据


printf("send message to server:");

 fgets(sendM,100,stdin);
int send_le;
 send_le=strlen(sendM);
sendM='\0';

 send(fd,sendM,strlen(sendM),0);

// 从服务器接收数据
if ((numbytes=recv(fd,receiveM,MAXDATASIZE,0)) == -1){
printf("recv() error\n");
exit(1);
}

 printf("receive message from server:%s\n",receiveM);

close(fd);

}</pre>
</div>
server.c
<div class="cnblogs_code">
<pre> #include <stdio.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include<pthread.h>
#define PORT 1234
#define BACKLOG 1

void *start_routine( void *ptr)
{
int fd = *(int *)ptr;
char buf[100];
 int numbytes;
int i,c=0;
printf("this is a new thread,you got connected\n");
printf("fd=%d\n",fd);

if ((numbytes=recv(fd,buf,100,0)) == -1){
printf("recv() error\n");
exit(1);
}

char str;
char buffer;

//将收到的字符串反转
for(c=0;c<(numbytes-1);c++)
{
buffer=buf;
}

 printf("receive message:%s\n",buf);

printf("numbytes=%d\n",numbytes);

for(i=0;i<numbytes;i++)
{
 str=buf;

}

printf("server will send:%s\n",str);
numbytes=send(fd,str,sizeof(str),0);
printf("send numbytes=%d\n",numbytes);
close(fd);
}

intmain()
{

int listenfd, connectfd;
struct sockaddr_in server;
struct sockaddr_in client;
int sin_size;
sin_size=sizeof(struct sockaddr_in);

pthread_t thread; //定义一个线程号

if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
 perror("Creating socket failed.");
 exit(1);
}

int opt = SO_REUSEADDR;
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

bzero(&server,sizeof(server));

server.sin_family=AF_INET;
server.sin_port=htons(PORT);
server.sin_addr.s_addr = htonl (INADDR_ANY);

// 绑定
if (bind(listenfd, (struct sockaddr *)&server, sizeof(struct sockaddr)) == -1) {
perror("Bind error.");
exit(1);
}

// 监听 
if(listen(listenfd,BACKLOG) == -1){/* calls listen() */
perror("listen() error\n");
exit(1);
}

while(1)
{
 // accept 
 if ((connectfd = accept(listenfd,(struct sockaddr *)&client,&sin_size))==-1) {
 perror("accept() error\n");
 exit(1);
 }

 printf("You got a connection from %s\n",inet_ntoa(client.sin_addr) );

 pthread_create(&thread,NULL,start_routine,(void *)&connectfd);

}
close(listenfd);

}</pre>
</div>
代码从U盘复制到home后，编译执行
打开三个中端
<img src="https://img2018.cnblogs.com/blog/1490994/201906/1490994-20190620103033826-1227731278.png">
 
可以发现用户端和服务器端连接成功，即用户端发送的信息，服务器端可以接收的到。
  
来源：https://www.cnblogs.com/weixinyu98/p/11057217.html

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Linux下实现客户端和服务器端的通信