Server socket

package com.www.test;

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

public class ReceiveSocket {

	final int RECEIVE_PORT = 9090;

	// 该服务器的端口号
	// ReceiveSocket的构造器
	public ReceiveSocket() {
		ServerSocket rServer = null;
		// ServerSocket的实例
		Socket request = null; // 用户请求的套接字
		Thread receiveThread = null;
		try {
			rServer = new ServerSocket(RECEIVE_PORT);
			// 初始化ServerSocket
			System.out.println("Welcome to the server!");
			System.out.println(new Date());
			System.out.println("The server is ready!");
			System.out.println("Port: " + RECEIVE_PORT);
			while (true) { // 等待用户请求
				request = rServer.accept();
				// 接收客户机连接请求
				receiveThread = new serverThread(request);
				// 生成serverThread的实例
				receiveThread.start();
				// 启动serverThread线程
			}
		} catch (IOException e) {
			System.out.println(e.getMessage());
		}
	}

	public static void main(String args[]) {
		new ReceiveSocket();
	} // end of main
}

// 类serverThread
class serverThread extends Thread {

	Socket clientRequest;
	// 用户连接的通信套接字
	BufferedReader input; // 输入流
	PrintWriter output; // 输出流

	public serverThread(Socket s) { // serverThread的构造器
		this.clientRequest = s;
		// 接收receiveServer传来的套接字
		InputStreamReader reader;
		OutputStreamWriter writer;
		try { // 初始化输入、输出流
			reader = new InputStreamReader(clientRequest.getInputStream());
			writer = new OutputStreamWriter(clientRequest.getOutputStream());
			input = new BufferedReader(reader);
			output = new PrintWriter(writer, true);
		} catch (IOException e) {
			System.out.println(e.getMessage());
		}
		output.println("Welcome to the server!");
		// 客户机连接欢迎词
		output.println("Now is:" + new java.util.Date() + " " + "Port:"
				+ clientRequest.getLocalPort());
		output.println("What can I do for you?");
	}

	public void run() { // 线程的执行方法
		String command = null; // 用户指令
		String str = null;
		boolean done = false;

		while (!done) {
			try {
				str = input.readLine(); // 接收客户机指令
			} catch (IOException e) {
				System.out.println(e.getMessage());
			}
			command = str.trim().toUpperCase();
			if (str == null || command.equals("QUIT"))
				// 命令quit结束本次连接
				done = true;
			else if (command.equals("HELP")) {
				// 命令help查询本服务器可接受的命令
				output.println("query");
				output.println("quit");
				output.println("help");
			} else if (command.startsWith("QUERY")) { // 命令query
				output.println("OK to query something!");
			}
			// else if …….. //在此可加入服务器的其他指令
			else if (!command.startsWith("HELP") && !command.startsWith("QUIT")
					&& !command.startsWith("QUERY")) {
				output.println("Command not Found!Please refer to the HELP!");
			}
		}// end of while
		try {
			clientRequest.close(); // 关闭套接字
		} catch (IOException e) {
			System.out.println(e.getMessage());
		}
		command = null;
	}// end of run
}