J2SE学习笔记（7）初谈通信

通讯麻烦的东西，弄些开胃的，下面的帖子还有料。

public   static   void  main(String[] args)  ... {
        
    InetAddress add= InetAddress.getLocalHost();
    System.out.println(add.getHostName());//主机名
     System.out.println(add.getHostAddress());//主机IP地址
     //机器名、域名、ip都可以
    InetAddress add1=   InetAddress.getByName("127.0.0.1");
    System.out.println(add1.getHostName());

    //编码
    String s=null;
    s = URLEncoder.encode("中国 china ","gb2312");
    System.out.println(s);
    System.out.println(URLDecoder.decode(s,"gb2312"));
}

 

// SOCKET套接字
//   与主机地址和端口地址相关联
//   客户端和服务器通过套接字建立连接和进行通信

// SOCKET分类

// TCP套接字
//  较可靠的双向流协议
//  发送任意数量的数据
//  提供消息确认、错误检测和错误恢复等服务
// UDP 套接字
//  比较不可靠


// tcp
public   class  Server  ... {
    
    public static void main(String[] args) ...{
        //注册自己时表示对客户端连接感兴趣
        ServerSocket s = null;
        Socket client = null;
        //创建服务端Socket   建立服务器和客户端之间的连接
        try ...{
             s = new ServerSocket(4700);
            //监听等待连接
             System.out.println("等待连接");
             //accept( ) 方法用于等待客户端触发通信
             client = s.accept();
             //获取socket 输入输出
             InputStream in = client.getInputStream();
             OutputStream out = client.getOutputStream();
             //向客户发送信息
             out.write(100);
             
             System.out.println("请输入：");
             InputStream sin = System.in;
             
             //对输出进行封装
             PrintWriter pw = new PrintWriter(out);
             //对键盘输入进行封装
             BufferedReader br = new BufferedReader(new InputStreamReader(sin));
             
             String msg = null;
             while (!(msg = br.readLine()).equals("exit"))...{
                 
                 pw.println(msg);
                 pw.flush();
             }
             
             in.read();
             
            System.out.println(client);
            System.out.println("wait for connect....");
        } catch (IOException e) ...{
            System.out.println("绑定端口出错");
            e.printStackTrace();
        }finally...{
            //关闭socket
            if(client!= null)
                try ...{
                    client.close();
                } catch (IOException e) ...{

                    e.printStackTrace();
                }
            if(s!=null)
                try ...{
                    s.close();
                } catch (IOException e) ...{
                    e.printStackTrace();
                }
            
        }
        
    }

}
// SOCKET通信实现过程-TCP
// 服务器端socket绑定于特定端口，服务器侦听socket等待连接请求
// 客户端向服务器和特定端口提交连接请求  
// 服务器接受连接，产生一新的socket，绑定到另一端口，由此socket来处理和客户端的交互，服务器继续侦听原socket来接受其他客户端的连接请求
// 连接成功后客户端也产生一socket，并通过它来与服务器端通讯（注意：客户端socket并不与特定端口绑定)
// 服务器端和客户端就通过读取和写入各自的socket来进行通讯。 
public   class  Client  ... {

    public static void main(String[] args) ...{
        // TODO 自动生成方法存根
        Socket client=null;
        try ...{
            client=new Socket("127.0.0.1",1860);
            
            InputStream in=client.getInputStream();
            OutputStream out=client.getOutputStream();
            
            PrintWriter pw=new PrintWriter(out);
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            BufferedReader buf=new BufferedReader(new InputStreamReader(in));
            String msg=null;
        while(!((msg=br.readLine()).equals("exit"))){
                pw.println(msg);
                pw.flush();
            }
            
            while((msg = br.readLine())!=null){
                
                System.out.println("server say:"+msg);
            }
            
            if(((msg=br.readLine()).equals("A")))
            ...{
                while(!((msg=br.readLine()).equals("exit")))...{
                    pw.println(msg);
                    pw.flush();
                }
            }
            else
            ...{
                while((msg = br.readLine())!=null)...{
                    
                    System.out.println("server say:"+msg);
                }
            }
            
            
            System.out.println(client);
        } catch (UnknownHostException e) ...{
            e.printStackTrace();
        } catch (IOException e) ...{
            e.printStackTrace();
        }finally...{
            if(client!=null)
                try ...{
                    client.close();
                } catch (IOException e) ...{
                    e.printStackTrace();
                }
        }
    }

}

// SOCKET通信实现过程-UDP
public   class  Pointer1  ... {    
    public static void main(String[] args) ...{        
        //创建数据报socket
        try ...{
            DatagramSocket ds = new DatagramSocket(8099);
            byte buf[] = new byte[1024];
            String s = "hello pointer2 ,i'm pointer1";
            buf = s.getBytes();
            //构造数据报文
            DatagramPacket packet = new DatagramPacket(
                    buf,
                    buf.length,
                    InetAddress.getLocalHost(),
                    1860
            );
            ds.send(packet);
            ds.close();
        } catch (SocketException e) ...{
            e.printStackTrace();
        } catch (UnknownHostException e) ...{
            e.printStackTrace();
        } catch (IOException e) ...{
            e.printStackTrace();
        }
    }
}

public   class  Pointer2  ... {
public static void main(String[] args) ...{
        //创建数据报socket
        try ...{
            DatagramSocket ds = new DatagramSocket(9001);
            //创建接收报文容器
            byte buf [] = new byte[1024];
            DatagramPacket packet = new DatagramPacket(buf,buf.length);
            System.out.println("等待数据");
            ds.receive(packet);
            String s = new String(packet.getData());
            System.out.println(s);
            ds.close();
        } catch (SocketException e) ...{
            e.printStackTrace();
        } catch (IOException e) ...{
            e.printStackTrace();
        }    
    }
}