[轉]Easy way for Java Socket Programing

Provider.java(TCP Server)

import java.io.*;
import java.net.*;
public class Provider{
	ServerSocket providerSocket;
	Socket connection = null;
	ObjectOutputStream out;
	ObjectInputStream in;
	String message;
	Provider(){}
	void run()
	{
		try{
			//1. creating a server socket
			providerSocket = new ServerSocket(2004, 10);
			//2. Wait for connection
			System.out.println("Waiting for connection");
			connection = providerSocket.accept();
			System.out.println("Connection received from " + connection.getInetAddress().getHostName());
			//3. get Input and Output streams
			out = new ObjectOutputStream(connection.getOutputStream());
			out.flush();
			in = new ObjectInputStream(connection.getInputStream());
			sendMessage("Connection successful");
			//4. The two parts communicate via the input and output streams
			do{
				try{
					message = (String)in.readObject();
					System.out.println("client>" + message);
					if (message.equals("bye"))
						sendMessage("bye");
				}
				catch(ClassNotFoundException classnot){
					System.err.println("Data received in unknown format");
				}
			}while(!message.equals("bye"));
		}
		catch(IOException ioException){
			ioException.printStackTrace();
		}
		finally{
			//4: Closing connection
			try{
				in.close();
				out.close();
				providerSocket.close();
			}
			catch(IOException ioException){
				ioException.printStackTrace();
			}
		}
	}
	void sendMessage(String msg)
	{
		try{
			out.writeObject(msg);
			out.flush();
			System.out.println("server>" + msg);
		}
		catch(IOException ioException){
			ioException.printStackTrace();
		}
	}
	public static void main(String args[])
	{
		Provider server = new Provider();
		while(true){
			server.run();
		}
	}
}

Requester.java(TCP Client)

import java.io.*;
import java.net.*;
import java.util.Scanner;

public class Requester{
	Socket requestSocket;
	ObjectOutputStream out;
 	ObjectInputStream in;
 	String message;
	Requester(){}
	void run()
	{
		try{
			
			Scanner scanner = new Scanner(System.in);
			System.out.print("Please input the IP: ");
			String host = scanner.next();
			
			//1. creating a socket to connect to the server
			requestSocket = new Socket(host, 2004);
			System.out.println("Connected to "+host+" in port 2004");
			//2. get Input and Output streams
			out = new ObjectOutputStream(requestSocket.getOutputStream());
			out.flush();
			in = new ObjectInputStream(requestSocket.getInputStream());
			//3: Communicating with the server
			do{
				try{
					message = (String)in.readObject();
					System.out.println("server>" + message);
					sendMessage("Hi my server");
					message = "bye";
					sendMessage(message);
				}
				catch(ClassNotFoundException classNot){
					System.err.println("data received in unknown format");
				}
			}while(!message.equals("bye"));
		}
		catch(UnknownHostException unknownHost){
			System.err.println("You are trying to connect to an unknown host!");
		}
		catch(IOException ioException){
			ioException.printStackTrace();
		}
		finally{
			//4: Closing connection
			try{
				in.close();
				out.close();
				requestSocket.close();
			}
			catch(IOException ioException){
				ioException.printStackTrace();
			}
		}
	}
	void sendMessage(String msg)
	{
		try{
			out.writeObject(msg);
			out.flush();
			System.out.println("client>" + msg);
		}
		catch(IOException ioException){
			ioException.printStackTrace();
		}
	}
	public static void main(String args[])
	{
		Requester client = new Requester();
		client.run();
	}
}

ref: http://zerioh.tripod.com/ressources/sockets.html