java socket server

package com.myserver.server;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class MultiThreadServer {

	private int port = 6666;
	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("server start");
	}

	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));
				Count.add();
				System.out.println("client number " + Count.num);
			} 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;
	}

	public void run() {
		try {
			System.out.println("a client connect " + socket.getInetAddress() + ":" + socket.getPort());
			PrintWriter writer = new PrintWriter(socket.getOutputStream());
			writer.println("connect success");
			writer.flush();
			BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
			String readLine = reader.readLine();
			while (true) {
				if (readLine != null) {
					System.out.println(readLine);
					readLine = reader.readLine();
				} else {
					break;
				}
			}
			writer.close();
			reader.close();
		} catch (IOException e) {
			System.out.println("a client leave");
			Count.sub();
			System.out.println("client number " + Count.num);
		} finally {
			try {
				if (socket != null) {
					socket.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}

class Count {
	public static int num = 0;

	public static void add() {
		num += 1;
	}

	public static void sub() {
		num -= 1;
	}
}