java tcp套接字编程

客户端

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class MultiJabberClient {
	static final int MAX_THREADS = 10;

	public void start() throws UnknownHostException, InterruptedException {
		InetAddress addr = InetAddress.getByName("bupt"); // 主机名
		while (true) {
			if (JabberClientThread.getThreadCount() < MAX_THREADS)
				new JabberClientThread(addr); // addr是服务器的地址

		}
	}

	public static void main(String args[]) throws UnknownHostException,
			InterruptedException {
		new MultiJabberClient().start();
	}
}

class JabberClientThread extends Thread {
	private static int counter = 0;
	private static int threadcount = 0;
	private int id = counter++;

	private Socket socket;
	private BufferedReader in;
	private PrintWriter out;

	public JabberClientThread(InetAddress addr) {
		System.out.println("Making Client " + id);
		threadcount++;

		try {
			socket = new Socket(addr, MultiJabberServer.PORT);
		} catch (IOException e) {

			e.printStackTrace();
		}
		try {
			in = new BufferedReader(new InputStreamReader(socket
					.getInputStream()));
			out = new PrintWriter(socket.getOutputStream(), true);

			start();
		} catch (IOException e) {
			e.printStackTrace();

			try {
				socket.close();
			} catch (IOException e1) {

				e1.printStackTrace();
			}
		}
	}

	public void run() {
		try {

			out.println("hello");
			out.println("bye");
			String str = in.readLine();
			System.out.println(str);
			// }

			out.println("END");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			System.out.println("Client " + id + " closing...");
			try {
				socket.close();
			} catch (IOException e) {

				e.printStackTrace();
			}
			threadcount--;
		}
	}

	public static int getThreadCount() {
		return threadcount;
	}
}

服务器端

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class MultiJabberServer {
	public static final int PORT = 8080; //端口可以任意指定大于1024的端口号
	
	public void start() throws IOException{
		ServerSocket s = new ServerSocket(PORT);
		System.out.println("Server started.");
		try{
			while(true){
				final Socket socket = s.accept();//阻塞，直到建立一个连接，通常，阻塞是由循环产生的。
				try{
					new ServerOneJabber(socket);          //监听到一个端口，就新建一个线程进行执行
				}
				catch(Exception e){
					socket.close();
				}
			}
		}
		finally{
			s.close();
		}
	}
	
	public static void main(String args[]) throws IOException{
		new MultiJabberServer().start();
	}

}

class ServerOneJabber extends Thread{
	private Socket socket;
	private BufferedReader in;
	private PrintWriter out;
	
	public ServerOneJabber(Socket s) throws IOException{
		socket = s;
		in = new BufferedReader(
				new InputStreamReader(socket.getInputStream()));  //负责读取来自客户端的请求
		out = new PrintWriter(socket.getOutputStream(), true);  //
用来向客户端会送响应的
		start();
	}

	public void run() {
		System.out.println(socket.getInetAddress()+":"+socket.getPort());
		try{
			while(true){
				String str = in.readLine();       //从客户端读取的字符串
							
				if(str.equals("END"))
					break;
				System.out.println("Echoing: " + str);
				out.println(str);
			}			
		}
		catch (IOException e) {
			e.printStackTrace();
		}
		finally{
			System.out.println("closing...");
			try {
				socket.close();
			} catch (IOException e) {
				
				e.printStackTrace();
			}
		}
	}
}