Socket TCP/UDP

---

TCP

TCPClient

package com.tcp;

import java.io.*;
import java.net.*;

class TCPClient 
{
    public static void main(String argv[]) throws Exception
    {
        String sentence;
        String modifiedSentence;
        BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
  
        Socket clientSocket = new Socket("127.0.0.1", 6789);
        DataOutputStream outToServer = 
　　　　　　　　new DataOutputStream(clientSocket.getOutputStream());
        BufferedReader inFromServer = 
　　　　　　　　new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        sentence = inFromUser.readLine();
        outToServer.writeBytes(sentence + '
');
        modifiedSentence = inFromServer.readLine();
        System.out.println("FROM SERVER: " + modifiedSentence);
        clientSocket.close();
    }
}

TCPServer

package com.tcp;

import java.io.*;
import java.net.*;

class TCPServer 
{
   public static void main(String argv[]) throws Exception
      {
         String clientSentence;
         String capitalizedSentence;
         ServerSocket welcomeSocket = new ServerSocket
         (6789);

         while(true) 
         {
            Socket connectionSocket = welcomeSocket.accept();
            
            BufferedReader inFromClient =
　　　　　　　　　　　new BufferedReader
　　　　　　　　　　(new InputStreamReader(connectionSocket.getInputStream()));
            
            DataOutputStream outToClient =
　　　　　　　　　　　new DataOutputStream(connectionSocket.getOutputStream());
            clientSentence = inFromClient.readLine();
            capitalizedSentence =  clientSentence.toUpperCase() + '
';
            outToClient.writeBytes(capitalizedSentence);
         }
      }
}

---

UDP

UDPClient

package com.udp;

import java.io.*;
import java.net.*;

class UDPClient 
{
   public static void main(String args[]) throws Exception
   {
      BufferedReader inFromUser =
　　　　　　　　new BufferedReader(new InputStreamReader(System.in));
      DatagramSocket clientSocket = new DatagramSocket();
      InetAddress IPAddress = InetAddress.getByName("localhost");
      byte[] sendData = new byte[1024];
      byte[] receiveData = new byte[1024];
      String sentence = inFromUser.readLine();
      sendData = sentence.getBytes();
      DatagramPacket sendPacket =
　　　　　　　　new DatagramPacket(sendData, sendData.length, IPAddress, 9876);
      clientSocket.send(sendPacket);
      DatagramPacket receivePacket =
　　　　　　　　new DatagramPacket(receiveData,receiveData.length);
      clientSocket.receive(receivePacket);
      String modifiedSentence = new String(receivePacket.getData());
      System.out.println("FROM SERVER:" +modifiedSentence);
      clientSocket.close();
   }
}

UDPServer

package com.udp;

import java.io.*;
import java.net.*;

class UDPServer 
{
   public static void main(String args[]) throws Exception
      {
         DatagramSocket serverSocket = new
                              DatagramSocket(9876);
            byte[] receiveData = new byte[1024];
            byte[] sendData = new byte[1024];
            while(true)
               {
                  DatagramPacket receivePacket =
　　　　　　　　　　　　　　new DatagramPacket(receiveData, receiveData.length);
                  serverSocket.receive(receivePacket);
                  String sentence = new String(receivePacket.getData());
                  InetAddress IPAddress = receivePacket.getAddress();
                  int port = receivePacket.getPort();
                  String capitalizedSentence = sentence.toUpperCase();
                  sendData = capitalizedSentence.getBytes();
                  DatagramPacket sendPacket =
　　　　　　　　　　　　　　new DatagramPacket(sendData,sendData.length, IPAddress, port);
                  serverSocket.send(sendPacket);
               }
      }
}