Java Learning--network programming

Udp

Encapsulates data and sources and purposes into packets without establishing a connection

Limit the size of each datagram within 64k

Because there is no connection, it is an unreliable agreement.

No need to establish connection, fast speed

Tcp

Establish a connection to form a channel for transmitting data

Make large data transfers in a connection

Complete connection via three handshake, is a reliable protocol

The connection must be established and the efficiency will be slightly lower

IP access:

Importjava.net.InetAddress;Importjava.net.UnknownHostException; Public classIpdemo { Public Static voidMain (string[] args)throwsunknownhostexception {//gets the local host IP address object. inetaddress IP =Inetaddress.getlocalhost (); //Gets the IP address object for the other host. ip = inetaddress.getbyname ("192.168.1.110"); //IP = inetaddress.getbyname ("My_think"); //IP = inetaddress.getbyname ("www.baidu.com");System.out.println (Ip.gethostaddress ());    System.out.println (Ip.gethostname ()); }}

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UDP protocol send side :

* Create the send side of the UDP transport.
Ideas
* 1, set up a UDP socket service.
* 2, the data to be sent is encapsulated in the packet.
* 3, send data packets via UDP socket service.
* 4, close the socket service.

 Public classUdpsenddemo { Public Static voidMain (string[] args)throwsIOException {System.out.println ("Send side start ..."); //1,udpsocket Services. Use the Datagramsocket object. Datagramsocket ds =NewDatagramsocket (8888); //2, the data to be sent is encapsulated in the packet. String str = "UDP Transport Demo: Buddy's Coming!" "; //use Datagrampacket to encapsulate the data into the package.         byte[] buf =str.getbytes (); Datagrampacket DP=NewDatagrampacket (Buf,buf.length,inetaddress.getbyname ("192.168.1.100"), 10000); //3, send the data packets through the socket service of UDP. Use the Send method. Ds.send (DP); //4, close the resource. Ds.close (); }}

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UDP protocol receive side :

* The idea of setting up a UDP receiving end.
* 1, to set up a UDP socket service, because it is to receive data, you must specify a port number.
* 2, create a packet to store the received data. It is convenient to parse the data with the method of the Packet object.
* 3, use the Receive method of the socket service to store the received data in a packet.
* 4. The data in the packet is parsed by means of a packet.
* 5, close resources

 Public classUdprecedemo { Public Static voidMain (string[] args)throwsIOException {System.out.println ("Receive-Side start ..."); //1, set up the UDP socket service. Datagramsocket ds =NewDatagramsocket (10000); //2. Create a packet.         byte[] buf =New byte[1024]; Datagrampacket DP=NewDatagrampacket (buf,buf.length); //3, use the Receive method to store the data in a packet. Ds.receive (DP);//a blocking type. //4, through the method of the packet object, parse the data, for example, address, port, data content. String IP =dp.getaddress (). gethostaddress (); intPort =Dp.getport (); String text=NewString (Dp.getdata (), 0, Dp.getlength ()); SYSTEM.OUT.PRINTLN (IP+ ":" +port+ ":" +text); //5, close the resource. Ds.close (); }}

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Not finished .....

Java Learning--network programming