socket programming in java

1// File Name GreetingServer.java
2import java.net.*;
3import java.io.*;
4
5public class GreetingServer extends Thread {
6   private ServerSocket serverSocket;
7   
8   public GreetingServer(int port) throws IOException {
9      serverSocket = new ServerSocket(port);
10      serverSocket.setSoTimeout(10000);
11   }
12
13   public void run() {
14      while(true) {
15         try {
16            System.out.println("Waiting for client on port " + 
17               serverSocket.getLocalPort() + "...");
18            Socket server = serverSocket.accept();
19            
20            System.out.println("Just connected to " + server.getRemoteSocketAddress());
21            DataInputStream in = new DataInputStream(server.getInputStream());
22            
23            System.out.println(in.readUTF());
24            DataOutputStream out = new DataOutputStream(server.getOutputStream());
25            out.writeUTF("Thank you for connecting to " + server.getLocalSocketAddress()
26               + "\nGoodbye!");
27            server.close();
28            
29         } catch (SocketTimeoutException s) {
30            System.out.println("Socket timed out!");
31            break;
32         } catch (IOException e) {
33            e.printStackTrace();
34            break;
35         }
36      }
37   }
38   
39   public static void main(String [] args) {
40      int port = Integer.parseInt(args[0]);
41      try {
42         Thread t = new GreetingServer(port);
43         t.start();
44      } catch (IOException e) {
45         e.printStackTrace();
46      }
47   }
48}

1// File Name GreetingClient.java
2import java.net.*;
3import java.io.*;
4
5public class GreetingClient {
6
7   public static void main(String [] args) {
8      String serverName = args[0];
9      int port = Integer.parseInt(args[1]);
10      try {
11         System.out.println("Connecting to " + serverName + " on port " + port);
12         Socket client = new Socket(serverName, port);
13         
14         System.out.println("Just connected to " + client.getRemoteSocketAddress());
15         OutputStream outToServer = client.getOutputStream();
16         DataOutputStream out = new DataOutputStream(outToServer);
17         
18         out.writeUTF("Hello from " + client.getLocalSocketAddress());
19         InputStream inFromServer = client.getInputStream();
20         DataInputStream in = new DataInputStream(inFromServer);
21         
22         System.out.println("Server says " + in.readUTF());
23         client.close();
24      } catch (IOException e) {
25         e.printStackTrace();
26      }
27   }
28}

1public class GreetServer {
2    private ServerSocket serverSocket;
3    private Socket clientSocket;
4    private PrintWriter out;
5    private BufferedReader in;
6
7    public void start(int port) {
8        serverSocket = new ServerSocket(port);
9        clientSocket = serverSocket.accept();
10        out = new PrintWriter(clientSocket.getOutputStream(), true);
11        in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
12        String greeting = in.readLine();
13            if ("hello server".equals(greeting)) {
14                out.println("hello client");
15            }
16            else {
17                out.println("unrecognised greeting");
18            }
19    }
20
21    public void stop() {
22        in.close();
23        out.close();
24        clientSocket.close();
25        serverSocket.close();
26    }
27    public static void main(String[] args) {
28        GreetServer server=new GreetServer();
29        server.start(6666);
30    }
31}

1$ java GreetingServer 6066
2Waiting for client on port 6066...
3

1Socket Programming