Customer advisory < socket programming based on UDP protocol (datagram socket) >

1, the construction method of Datagrampacket class

2, the construction method of Datagramsocket class

3. Common methods of Datagramsocket class

4. Service Side

 package com.ljb.app.datagram;import java.io.IOException;import java.net.DatagramPacket; import java.net.datagramsocket;import java.net.socketaddress;import java.net.socketexception;/* * *  Customer Advisory Service  *  @author  LJB *  @version  2015 March 12  */public  class askserver { /**  *  @param  args  */ public static  void main (String[] args)  {  try {   //  Create receiver Sockets (server), and bind the port number    datagramsocket ds = new datagramsocket (8800);    //   Determines the size of the array of data received by the packet    byte[] buf = new byte[1024];       //  Create a packet of the receiving type, and the data is stored in the array    DatagramPacket dp = new  Datagrampacket (buf,buf.length);      //  receive data via sockets     Ds.receive (DP);       //  parsing the data sent by the sender    string mess = new string (buf   0 , dp.getlength ());    SYSTEM.OUT.PRINTLN ("client says:"  + mess);       //  response Information    String reply =  "Hello, I am in, please inquire." ";    byte[] buf2 = reply.getbytes ();      //  Response Address    socketaddress sa = dp.getsocketaddress ();       //  packet    datagrampacket dp2 = new datagrampacket (buf2 ,  BUF2.LENGTH , SA);      //  send    ds.send (DP2) ;      //  Release Resources    ds.close ();  } catch  ( socketexception e)  {   e.printstacktrace ();  } catch  (IOException  e)  {  &nbsP;e.printstacktrace ();   }     }} 

5, client

Package com.ljb.app.datagram;import java.io.ioexception;import java.net.datagrampacket;import  java.net.datagramsocket;import java.net.inetaddress;import java.net.socketexception;import  java.net.UnknownHostException;/** *  Customer Advisory Client  *  @author  LJB *  @version  2015 March 12  */public class AskClient { /**  *  @param  args   */ public static void main (String[] args)  {  //  Determine the information sent to the server, server address, Port   String mess =  "Hello, I want to ask a question?" ";   byte[] buf = mess.getbytes ();     inetaddress ia =  null;  try {   ia = inetaddress.getbyname ("localhost");   } catch  (unknownhostexception e)  {   e.printstacktrace ();   }    int port = 8800;    //  Create a packet, send the specified length of information to the specified port on the specified server   DatagramPacket dp = new  Datagrampacket (Buf , buf.length , ia , port);    //  Create a Socket object   datagramsocket ds = null;  try {   ds =  new datagramsocket ();  } catch  (socketexception e)  {    e.printstacktrace ();  }    //  send packet   try {    ds.send (DP);  } catch  (IOEXCEPTION E)  {   e.printstacktrace ();  }    //  create receive array   byte[] buf2 = new byte[ 1024];    //  creating a Receive packet   DatagramPacket dp2 = new  Datagrampacket (buf2 , buf2.length);    //  receive data   try {    ds.receive (DP2);  &nBSP;}  catch  (ioexception e)  {   e.printstacktrace ();  }     //  parse the received data   string reply = new string (buf2 , 0  ,  dp2.getlength ());   system.out.println ("server-side said:"  + reply);     //   Release Resources   ds.close ();  }}

Operation Result:

Service side:

Client said: Hello, I would like to ask a question?

Client:

Server side said: Hello, I am in, please consult.

Customer advisory < socket programming based on UDP protocol (datagram socket) >