1 #ifndef NETINFORMATION_H
 2 #define NETINFORMATION_H
 3 
 4 #include <netdb.h>//包含gethostbyname gethostbyaddr
 5 #include <netinet/in.h>
 6 class NetInformation
 7 {
 8     private:
 9 
10             struct hostent *hostInformation;
11             struct servent *hostServer;
12 
13     public:
14             void reset();
15 
16             void getHostInfoByAddr();
17             void getHostInfoByName();
18             void printHostInformation();
19 
20             void getHostServer(const char *name,const char *proto);
21             void getHostServer(int port,const char *proto);
22             void printHostServer();
23 
24 
25 };
26 
27 #endif

  1 #include "NetInformation.h"
  2 
  3 
  4 #include <unistd.h>//包含 gethostname
  5 #include <netinet/in.h>//此文件中包含 in_addr
  6 #include <arpa/inet.h> //此文件中包含 inet_ntoa
  7 #include <iostream>
  8 #include <cstring>
  9 using std::cout;
 10 using std::endl;
 11 
 12 
 13 void NetInformation::getHostInfoByName()
 14 {
 15     char hostName[256];
 16 
 17     if(gethostname(hostName,255)==0) ;//成功时返回0，失败时返回－1
 18         else cout<<"gethostname failed";
 19     hostInformation=gethostbyname(hostName);
 20 }
 21 
 22 void NetInformation::getHostInfoByAddr()
 23 {
 24     struct in_addr hostAddr;
 25     char addr[12];
 26 
 27     strcpy(addr,"127.0.0.1");
 28     inet_aton(addr,&hostAddr);
 29     hostInformation=gethostbyaddr(&hostAddr,sizeof(&hostAddr),AF_INET);
 30 }
 31 
 32 void NetInformation::printHostInformation()
 33 {
 34       char **ptr,**pptr,str[32];
 35       cout<<"主机名:"<<hostInformation->h_name<<endl;
 36 
 37       cout<<"主机别名:";
 38       ptr = hostInformation->h_aliases;
 39       if(*ptr==0)
 40         cout<<"没有查询到主机别名";
 41         while(*ptr)
 42         {
 43             cout<<*ptr;
 44             ++ptr;
 45         };
 46       cout<<endl;
 47 
 48     //根据地址类型，将地址打出来
 49     switch(hostInformation->h_addrtype)
 50     {
 51             case AF_INET:
 52             case AF_INET6:
 53                     pptr=hostInformation->h_addr_list;
 54                     //将刚才得到的所有地址都打出来。其中调用了inet_ntop()函数
 55                     while(*pptr)
 56                          {
 57                              cout<<"主机地址："<<inet_ntop(hostInformation->h_addrtype, *pptr, str, sizeof(str));
 58                              ++pptr;
 59                          }
 60                     cout<<endl;
 61                     break;
 62             default:
 63                     cout<<"unknown address type\n";
 64                     break;
 65     }
 66 }
 67 
 68 void NetInformation::getHostServer(const char *name,const char *proto)
 69 {
 70     hostServer=getservbyname(name,proto);
 71 }
 72 
 73 void NetInformation::getHostServer(int port,const char *proto)
 74 {
 75     hostServer=getservbyport(port,proto);
 76 }
 77 
 78 void NetInformation::printHostServer()
 79 {
 80     if(hostServer!=0)
 81     {
 82         cout<<"服务名   :"<<hostServer->s_name<<endl;
 83 
 84         char **alisases=hostServer->s_aliases;
 85         cout<<"服务别名：";
 86         if(*alisases==0) cout<<"未查询到别名"<<endl;
 87         else
 88         {
 89             while(*alisases)
 90             {
 91                 cout<<*alisases;
 92                 ++alisases;
 93             }
 94             cout<<endl;
 95         }
 96         cout<<"端口号:"<<hostServer->s_port<<endl;
 97         cout<<"套接字类型:"<<hostServer->s_proto<<endl;
 98     }
 99 }
100 
101 void NetInformation::reset()
102 {
103     hostInformation=0;
104     hostServer=0;
105 
106 }

#include <iostream>
#include <unistd.h>
#include <netinet/in.h>
#include "NetInformation.h"
using namespace std;
int main()
{
    NetInformation test;
    cout<<"/**<  方式一*/"<<endl;

    test.getHostInfoByName();
    test.printHostInformation();
    cout<<"/**< 方式二 */"<<endl;
    test.reset();
    test.getHostInfoByAddr();
    test.printHostInformation();

    cout<<"/**< 方式三 */"<<endl;
    test.reset();
    test.getHostServer("daytime","tcp");
    test.printHostServer();

    cout<<"/**< 方式四 */"<<endl;
    test.reset();
    test.getHostServer(3328,"tcp");
    test.printHostServer();
    return 0;
}