1、Server
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.*;
import java.util.concurrent.*;
public class MultiThreadServer {
	private int port = 8821;
	private ServerSocket serverSocket;
	private ExecutorService executorService;// 线程池
	private final int POOL_SIZE = 10;// 单个CPU线程池大小
	public MultiThreadServer() throws IOException {
		serverSocket = new ServerSocket(port);
		// Runtime的availableProcessor()方法返回当前系统的CPU数目.
		executorService = Executors.newFixedThreadPool(Runtime.getRuntime()
				.availableProcessors() * POOL_SIZE);
		System.out.println("服务器启动");
	}
	public void service() {
		while (true) {
			Socket socket = null;
			try {
				// 接收客户连接,只要客户进行了连接,就会触发accept();从而建立连接
				socket = serverSocket.accept();
				executorService.execute(new Handler(socket));
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) throws IOException {
		new MultiThreadServer().service();
	}
}
class Handler implements Runnable {
	private Socket socket;
	public Handler(Socket socket) {
		this.socket = socket;
	}
	private PrintWriter getWriter(Socket socket) throws IOException {
		OutputStream socketOut = socket.getOutputStream();
		return new PrintWriter(socketOut, true);
	}
	private BufferedReader getReader(Socket socket) throws IOException {
		InputStream socketIn = socket.getInputStream();
		return new BufferedReader(new InputStreamReader(socketIn));
	}
	public String echo(String msg) {
		return "echo:" + msg;
	}
	public void run() {
		try {
			System.out.println("New connection accepted "
					+ socket.getInetAddress() + ":" + socket.getPort());
			BufferedReader br = getReader(socket);
			PrintWriter pw = getWriter(socket);
			String msg = null;
			while ((msg = br.readLine()) != null) {
				System.out.println(msg);
				pw.println(echo(msg));
				if (msg.equals("bye"))
					break;
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if (socket != null)
					socket.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class MultiThreadClient {
	public static void main(String[] args) {
		int numTasks = 10;
		ExecutorService exec = Executors.newCachedThreadPool();
		for (int i = 0; i < numTasks; i++) {
			exec.execute(createTask(i));
		}
	}
	// 定义一个简单的任务
	private static Runnable createTask(final int taskID) {
		return new Runnable() {
			private Socket socket = null;
			private int port = 8821;
			public void run() {
				System.out.println("Task " + taskID + ":start");
				try {
					socket = new Socket("localhost", port);
					// 发送关闭命令
					OutputStream socketOut = socket.getOutputStream();
					socketOut.write("shutdown\r\n".getBytes());
					// 接收服务器的反馈
					BufferedReader br = new BufferedReader(
							new InputStreamReader(socket.getInputStream()));
					String msg = null;
					while ((msg = br.readLine()) != null)
						System.out.println(msg);
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		};
	}
}原文:http://blog.csdn.net/shmnh/article/details/44523469