Java UDP Programming

1. Client code

1 Importjava.io.IOException;2 ImportJava.net.DatagramPacket;3 ImportJava.net.DatagramSocket;4 Importjava.net.InetAddress;5 6  Public classUdpClient {7      Public Static voidMain (string[] args)throwsIOException {8         //1. Define the server's address, port number, data9InetAddress address = Inetaddress.getbyname ("localhost");Ten         intPort = 8800; One         byte[] data = "User name: admin; Password: 123 ". GetBytes (); A         //2. Create a datagram that contains the sent data information -Datagrampacket packet =Newdatagrampacket (data, data.length,address,port); -         //3. Create a Datagramsocket object theDatagramsocket socket =NewDatagramsocket (); -         //4. Sending datagrams to the server side - socket.send (packet); -         /** + * Receive server-side response data -          */ +         //1. Create datagrams to receive data from server-side responses A         byte[] Data2 =New byte[1024]; atDatagrampacket Packet2 =NewDatagrampacket (data2, data2.length); -         //2. Receiving server response data - socket.receive (Packet2); -         //3. Reading data -String reply =NewString (data2, 0, Packet2.getlength ()); -System.out.println ("I am the client, I received the server information:" +reply); in         //4. Close Resources - socket.close (); to     } +}

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2. Server-side code

1 Importjava.io.IOException;2 ImportJava.net.DatagramPacket;3 ImportJava.net.DatagramSocket;4 Importjava.net.InetAddress;5 /**6  * 7 * UDP Server side8  *9  */Ten  Public classUdpserver { One      Public Static voidMain (string[] args)throwsIOException { A     //1. Create a server-side datagramsocket, specify the port -Datagramsocket socket =NewDatagramsocket (8800); -     //2. Create a datagram to receive data sent by the client the     byte[] data =New byte[1024];//creates a byte array that specifies the size of the received packet.  -Datagrampacket packet =Newdatagrampacket (data, data.length); -     //3. Receiving data sent by the client -SYSTEM.OUT.PRINTLN ("* * * Server has been started, waiting for client to send information"); +Socket.receive (packet);//This method will block until the datagram is received -     //4. Reading data +String info =NewString (data, 0, Packet.getlength ()); ASystem.out.println ("I am the server, the client says:" +info); at      -     /** - * Response data to the client -      */ -     //1. Define the client's address, port number, data -InetAddress address =packet.getaddress (); in     intPort =Packet.getport (); -     byte[] Data2 = "Welcome you!" ". GetBytes (); to     //Send data to client +Datagrampacket Packet2 =NewDatagrampacket (data2, data2.length,address,port); - socket.send (Packet2); the     //4. Close the socket * socket.close (); $     }Panax Notoginseng}

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Java UDP Programming