Socket网络通信之发送数据包

        socket->abort();
        socket->connectToHost(IP_now,PORN_now.toInt());
        
        HEAD_T head;
        head.fun=1;
        
        LOGIN_M login;
        QByteArray name =this->NameEdit->text().toLatin1();
        QByteArray pwd =this->PwdEdit->text().toLatin1();
        strcpy(login.username,name.data());
        strcpy(login.passwd,pwd.data());
        
        char *data=new char[1024];
        memcpy(data,&head,sizeof(HEAD_T));
        memcpy(data+sizeof(HEAD_T),&login,sizeof(LOGIN_M));
        socket->write(data,sizeof(HEAD_T)+sizeof(LOGIN_M));

#include <stdlib.h>
#include <stdio.h>  
#include <errno.h>  
#include <string.h>  
#include <netdb.h>  
#include <sys/types.h>  
#include <netinet/in.h>  
#include <sys/socket.h>    
#include "sqlite3.h"

#define portnumber //端口号，自己设置   

int main(int argc, char *argv[])
{   	
	//截取字符串
	HEAD_T head;
	LOGIN_M login_m;
	LOGIN_S login_s;
	char data[1024];
	int num = 0;
	int nbytes;  
	char buffer[1024];
	
   	 char *errMsg;
   	 int rc;

	
	//设置Socket属性：SO_REUSEADDR：允许在bind过程中本地地址重复使用   
	int iSockopt = 1;
	if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, 
		(const char *)&iSockopt, sizeof(int)) < 0 )
	{   
		close(sockfd);   
		return -1;   
	}
	
	while(1)   
	{    
		/* 服务器阻塞,直到客户程序建立连接 */    
		sin_size=sizeof(struct sockaddr_in);    
		if((new_fd=accept(sockfd,(struct sockaddr *)(&client_addr),&sin_size))==-1)    
		{     
			fprintf(stderr,"Accept error:%sna",strerror(errno));     
			exit(1);    
		}    
		fprintf(stderr,"Server get connection from %sn",inet_ntoa(client_addr.sin_addr)); // 将网络地址转换成.字符串
		
		
		if((nbytes=read(new_fd,buffer,1024))==-1)    
		{     	
			printf("%d",nbytes);
			fprintf(stderr,"Read Error:%sn",strerror(errno));     
			exit(1);    
		} 
		
		//下面开始解包
		buffer[nbytes]=''; 
		ptr = buffer;
		memcpy(&head,ptr,sizeof(HEAD_T));
		num=head.fun;

   		switch(num)
		{
			case 0://确定连上服务器
				{
					login_s.flag=1;
					printf("ncase=%dn",num);
					 memcpy(data,&head,sizeof(HEAD_T));
					 memcpy(data+sizeof(HEAD_T),&login_s,sizeof(login_s));
					write(new_fd,data,sizeof(login_s)+sizeof(head)); 
					memset(data,0,sizeof(data));
					memset(buffer,0,sizeof(buffer));
					memset(&login_s,0,sizeof(login_s));
					//memset(login_m,0,sizeof(login_m));
					ptr=NULL;
					
					
				}
			break;
			case 1://登录
				printf("ncase=%dn",num);
				memcpy(&login_m,ptr+sizeof(HEAD_T),sizeof(LOGIN_M));
				sprintf(sql,"select * from user where name = '%s'and pwd = '%s'",
				login_m.username,login_m.passwd);
				rc = sqlite3_get_table(db,sql,&dbResult,&nRow,&nColumn,&errMsg);
				if(rc == SQLITE_OK && nRow == 1)	
				{		
					login_s.flag=1;
					//printf("fun=%d",head.fun);
 					memcpy(data,&head,sizeof(HEAD_T));
					memcpy(data+sizeof(HEAD_T),&login_s,sizeof(login_s));
					write(new_fd,data,sizeof(login_s)+sizeof(head)); 
					printf("nlogin succsen");
					
				}
				else if(rc != SQLITE_OK || nRow != 1)	
				{		
					login_s.flag=0;
 					memcpy(data,&head,sizeof(HEAD_T));
					memcpy(data+sizeof(HEAD_T),&login_s,sizeof(login_s));
					write(new_fd,data,sizeof(data));
					printf("nlocin error");  
					
				}
			ptr=NULL;
			break;
			case 2://
				printf("case=%dn",num);
				memcpy(&login_m,ptr+sizeof(HEAD_T),sizeof(LOGIN_M));
				sprintf(sql,"insert into user values ('%s','%s',0,'0','0')",
				login_m.username,login_m.passwd);
				rc = sqlite3_get_table(db,sql,&dbResult,&nRow,&nColumn,&errMsg);
				if(rc==SQLITE_OK)
					printf(" nadd successn");
			ptr=NULL;
				break; 
			
			case 3://
				printf("case=%dn",num);
				memcpy(&login_m,ptr+sizeof(HEAD_T),sizeof(LOGIN_M));
				printf("admin=%s,pwd=%s",login_m.username,login_m.passwd);
				sprintf(sql,"update user set pwd = '%s' where name = '%s'",
				login_m.passwd,login_m.username);
				rc = sqlite3_get_table(db,sql,&dbResult,&nRow,&nColumn,&errMsg);
				if(rc==SQLITE_OK)
					printf("n updata successn");
			ptr=NULL;
				break; 
		}
  
		printf("nServer received %sn",buffer);      //这个通讯已经结束     
	
		close(new_fd);    /* 循环下一个 */   
	}    /* 结束通讯 */
	
	close(sockfd);   
	exit(0);  
}