用ACE的Reactor模式实现网络通讯的例子，不罗嗦，直接上代码。

服务器代码：

#include <ace/Reactor.h>
#include <ace/SOCK_Connector.h> 
#include <ace/SOCK_Acceptor.h> 
#include <ace/Auto_Ptr.h>


class ClientService : public ACE_Event_Handler
{
public:
    ACE_SOCK_Stream &peer (void) { return this->sock_; }

    int open (void)
    {
        //注册读就绪回调函数
        return this->reactor ()->register_handler(this,ACE_Event_Handler::READ_MASK);
    }

    virtual ACE_HANDLE get_handle (void) const { return this->sock_.get_handle (); }

    virtual int handle_input (ACE_HANDLE fd )
    {
        int rev = peer().recv(buf,sizeof(buf));
        if(rev<=0)
            return -1;
		buf[rev] = '\0';
		printf("recv: %s",buf);
		strcpy(buf,"hello,Client\n");
        peer().send(buf,strlen(buf)); //向客户端发送信息。
        return 0;
    }

    // 释放相应资源
virtual int handle_close (ACE_HANDLE,ACE_Reactor_Mask mask)
    {
        if (mask == ACE_Event_Handler::WRITE_MASK)
            return 0;
        mask = ACE_Event_Handler::ALL_EVENTS_MASK |
            ACE_Event_Handler::DONT_CALL;
        this->reactor ()->remove_handler (this,mask);
        this->sock_.close ();
        delete this;    //socket出错时，将自动删除该客户端，释放相应资源
        return 0;
    }

protected:
    char buf[100];
    ACE_SOCK_Stream sock_;
};


class ClientAcceptor : public ACE_Event_Handler
{
public:
    virtual ~ClientAcceptor (){this->handle_close (ACE_INVALID_HANDLE,0);}

    int open (const ACE_INET_Addr &listen_addr)
    {
        if (this->acceptor_.open (listen_addr,1) == -1)
        {
            printf("open port fail\n");
            return -1;
        }
        //注册接受连接回调事件
        return this->reactor ()->register_handler(this,ACE_Event_Handler::ACCEPT_MASK);
    }

    virtual ACE_HANDLE get_handle (void) const
    { return this->acceptor_.get_handle (); }

    virtual int handle_input (ACE_HANDLE fd )
    {
        ClientService *client = new ClientService();
        auto_ptr<ClientService> p (client);

        if (this->acceptor_.accept (client->peer ()) == -1)
        {
            printf("accept client fail\n");
            return -1;
        }
        p.release ();
        client->reactor (this->reactor ());
        if (client->open () == -1)
            client->handle_close (ACE_INVALID_HANDLE,0);
        return 0;
    }
    
    virtual int handle_close (ACE_HANDLE handle,ACE_Reactor_Mask close_mask)
    {
        if (this->acceptor_.get_handle () != ACE_INVALID_HANDLE)
        {
            ACE_Reactor_Mask m = ACE_Event_Handler::ACCEPT_MASK |
                ACE_Event_Handler::DONT_CALL;
            this->reactor ()->remove_handler (this,m);
            this->acceptor_.close ();
        }
        return 0;
    }

protected:
    ACE_SOCK_Acceptor acceptor_;
};

int main(int argc,char *argv[]) 
{
    ACE_INET_Addr addr(3000,"127.0.0.1");
    ClientAcceptor server;
    server.reactor(ACE_Reactor::instance());
    server.open(addr);

    while(true)
    {
        ACE_Reactor::instance()->handle_events(); 
    }

    return 0; 
} 

客户端代码：

#include "ace/Reactor.h"
#include "ace/SOCK_Connector.h"

#include <string>
#include <iostream>
using namespace std;

class MyClient:public ACE_Event_Handler 
{
public:
    bool open()
    {
        ACE_SOCK_Connector connector;
        ACE_INET_Addr addr(3000,"127.0.0.1");
        ACE_Time_Value timeout(5,0);
        if(connector.connect(peer,addr,&timeout) != 0)
        {
            cout<<endl<<"connect fail.";
            return false;
        }
        ACE_Reactor::instance()->register_handler(this,ACE_Event_Handler::READ_MASK);
        cout<<endl<<"connected.";
		strcpy(buf,Server\n");
		peer.send(buf,strlen(buf));
        return true;
    }

    ACE_HANDLE get_handle(void) const
    {
        return peer.get_handle();
    }

    int handle_input (ACE_HANDLE fd)
    {
        int rev=0;
        ACE_Time_Value timeout(5,0);
        if((rev=peer.recv(buf,sizeof(buf),&timeout))>0)
        {
            buf[rev]='\0';
            cout<<endl<<"recv: "<<buf<<endl;
        }
        return 3;
    }

private:
    ACE_SOCK_Stream peer;
    char buf[100];
};

int main(int argc,char *argv[]) 
{
    MyClient client;
    client.open();

    while(true)
    {
        ACE_Reactor::instance()->handle_events(); 
    }

    return 0; 
}

分别编译运行（先运行服务端，后运行客户端）下面是执行结果。

服务器：

recv: hello,Server

客户端：

connected.
recv: hello,Client

参考：

http://www.cnblogs.com/TianFang/archive/2006/12/13/591332.html

http://www.cnblogs.com/TianFang/archive/2006/12/18/595938.html