一台主机取另一台主机上的日期时间（java多线程。网络编程实现）

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实现机制：
1，主机a，客户机b
2，主机a不断轮训接受客户机b的连接，客户机连接就开启一个新的线程，该线程启动一个定时任务每隔一段时间，发送主机a上的日期时间，给客户机。
3，客户机b连接上主机a上，不断监听接受主机a发送的字符，一旦检测到a有日期时间发送过来，就立马更新本机的日期时间。
4，本博文实例所有配置在配置文件中配置。
5，博文实例采用cs模式。
6，本博文主机代码，和客户机代码可分别打包成可运行的jar文件分布在不同的机器上运行。

代码：
服务端：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import java.util.Timer;
import java.util.TimerTask;

public class Server {
	SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

	ServerSocket serverSocket = null;
	int port = 0;
	private BufferedReader in = null;
	private PrintWriter out = null;

	public Server() throws Exception {
		sf.setTimeZone(TimeZone.getTimeZone("GMT+8:00"));
		port = new Integer(Utils.getServerProperties()[0]).intValue(); // 利用工具类读取配置文件把得到的字符串端口号转换为int类型的。
		serverSocket = new ServerSocket(port);
		System.out.println("Server port is: " + port);
		System.out.println("Server starting time is: " + sf.format(new Date()));
		System.out.println("Server is running…………");
		System.out.println("**********************");
		System.out.println();
		while (true) // 无限死循环，时刻监听客户端的请求。
		{
			Socket socket = serverSocket.accept();
			System.out.println(socket.getInetAddress().getHostAddress() + "  "
					+ "on the time : " + sf.format(new Date())
					+ "  connected the server。");
			this.in = new BufferedReader(new InputStreamReader(
					socket.getInputStream(), "GB2312"));
			this.out = new PrintWriter(socket.getOutputStream(), true);
			new MyThread(socket, in, out).start(); // 客户端一旦建立连接就生成一个线程
		}
	}

	public static void main(String[] args) throws Exception {
		System.out.println();
		System.out.println("**********************");
		System.out.println("Date and time server is starting…………");
		System.out.println("Version： 2.0");
		new Server();
	}
}

class MyThread extends Thread // 每一个连接都生成一个线程
{
	private BufferedReader in = null;
	private PrintWriter out = null;

	public MyThread(Socket socket, BufferedReader in, PrintWriter out)
			throws Exception // 无参数构造函数
	{
		this.in = in;
		this.out = out;
	}

	public void run() {
		MyTask task = new MyTask(in, out);
		Timer timer = new Timer();
		timer.schedule(task, 10000,
				new Integer(Utils.getServerProperties()[2]).intValue()); // 定时器，每隔一定时间给客户端发送一个服务器上的时间，客户端接收到数据后对本地日期和时间进行更行
	}
}

class MyTask extends TimerTask {

	// private BufferedReader in = null;
	private PrintWriter out = null;
	String dateAndTime = null;

	public MyTask(BufferedReader in, PrintWriter out) {
		// this.in = in;
		this.out = out;
	}

	public void run() {
		dateAndTime = Utils.getDateAndTime();
		dateAndTime = dateAndTime + "-" + Utils.getServerProperties()[2];
		out.println(dateAndTime);
	}
}

客户端：

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

public class Client
{
	Socket socket = null;
	private BufferedReader in = null;
	// private PrintWriter out = null;
	String serverDateAndTime[] = null;
	int period = 0;

	public Client() throws Exception
	{

		System.out.println("Client is starting……");
		String[] ServerIpAndPort = Utils.getServerIpAndPortProperties(); // 得到客户端配置文件的属性值
		System.out.println("The server ip address is: " + ServerIpAndPort[0]);
		System.out.println("The server port is :" + ServerIpAndPort[1]);
		System.out.println("Connecting server………………");
		try
		{
			this.socket = new Socket(ServerIpAndPort[0], Integer.valueOf(
					ServerIpAndPort[1]).intValue());
			this.in = new BufferedReader(new InputStreamReader(
					socket.getInputStream(), "GB2312"));
			// this.out = new PrintWriter(socket.getOutputStream(), true);
		} catch (NumberFormatException e)
		{
			System.out
					.println("Connecting server occured exception, please check netword and properties files .");
			System.out.println("Client will exit afiter 10 seconds .");
			Utils.pause(10000);
			System.exit(0);
		} catch (UnknownHostException e)
		{
			System.out
					.println("Connecting server occured exception, please check netword and properties files .");
			System.out.println("Client will exit afiter 10 seconds .");
			Utils.pause(10000);
			System.exit(0);
		} catch (IOException e)
		{
			System.out
					.println("Connecting server occured exception, please check netword and properties files .");
			System.out.println("Client will exit afiter 10 seconds .");
			Utils.pause(10000);
			System.exit(0);
		}
		System.out.println("Connected the server successfully .");

		while (true)
		{
			System.out.println();
			serverDateAndTime = in.readLine().split("-");
			System.out.println();
			System.out.println();
			System.out.println("*************************");

			System.out.println("The time of this update is ："
					+ serverDateAndTime[0] + "-" + serverDateAndTime[1] + "-"
					+ serverDateAndTime[2] + "-" + serverDateAndTime[3] + "-"
					+ serverDateAndTime[4] + "-" + serverDateAndTime[5] + "-"
					+ serverDateAndTime[6] + " .");
			period = new Integer(serverDateAndTime[7]).intValue();

			System.out.println("Starting update local date and time .");
			Utils.setDateAndTime(serverDateAndTime);
			System.out.println("Update successfully .");
			System.out.println("Server will update local date and time after "
					+ period / 3600000 + " hours .");
			System.out.println("*************************");
		}
	}

	public static void main(String[] args) throws Exception
	{
		try
		{
			new Client();
		} catch (java.net.SocketException e)
		{
			System.out.println("Connecting server failed");
			new Client();
		}

	}
}

工具类：

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Calendar;
import java.util.Properties;
import java.util.TimeZone;

public class Utils
{
	private static TimeZone tz = TimeZone.getTimeZone("GMT+8:00"); // 设置北京时区
	private static Calendar Cld = null;
	private static int year;
	private static int month;
	private static int day;
	private static int hour;
	private static int minute;
	private static int second;
	private static int milliSecont;
	private static StringBuffer dateAndTimeTemp = null;
	private static String dateAntTime = null;
	private static String command1;
	private static String command2;

	public static String getDateAndTime() // 获得客户机请求时的系统日期和时间函数（精确到毫秒）
	{
		Cld = Calendar.getInstance(tz); // 得到北京时区的日期和时间
		year = Cld.get(Calendar.YEAR);
		month = Cld.get(Calendar.MONTH) + 1;
		day = Cld.get(Calendar.DATE);
		hour = Cld.get(Calendar.HOUR_OF_DAY); // 得到二十四小时中的小时
		minute = Cld.get(Calendar.MINUTE);
		second = Cld.get(Calendar.SECOND);
		milliSecont = Cld.get(Calendar.MILLISECOND);
		dateAndTimeTemp = new StringBuffer();
		dateAndTimeTemp.append(year).append("-").append(month).append("-")
				.append(day).append("-").append(hour).append("-")
				.append(minute).append("-").append(second).append("-")
				.append(milliSecont);
		dateAntTime = dateAndTimeTemp.toString();
		return dateAntTime;
	}

	public static String[] getServerProperties() // 得到服务端配置文件ServerPort.properties的属性值
	{
		String ServerProperties[] = new String[3];
		InputStream inputStream = null;
		try
		{
			inputStream = new FileInputStream("ServerPort.properties");
		} catch (FileNotFoundException e1)
		{
			System.out
					.println("配置文件ServerPort.properties找不到，请检查该文件是否存在，之后重启本程序，程序将在10秒钟后自动关闭。");
			pause(10000);
			System.exit(0);
		}
		Properties p = new Properties();
		try
		{
			p.load(inputStream);
		} catch (IOException e)
		{
			System.out
					.println("读取配置文件ServerPort.properties时程序出现异常，请检查该文件名是否正确，该文件是否存在，之后重启本程序。程序将在10秒钟后自动关闭");
			pause(10000);
			System.exit(0);
		}
		ServerProperties[0] = p.getProperty("ServerPort");
		ServerProperties[1] = p.getProperty("delay");
		ServerProperties[2] = p.getProperty("period");
		return ServerProperties;
	}

	public static String[] getServerIpAndPortProperties() // 得到客户端配置文件ServerIpAndPort.properties的属性值
	{
		String[] ServerIpAndPort = new String[2];
		Properties p = new Properties();
		try
		{
			InputStream inputStream = new FileInputStream(
					"ServerIpAndPort.properties");
			p.load(inputStream);
		} catch (IOException e)
		{
			System.out.println("读取配置文件ServerIpAndPort.properties时程序出现异常。");
			System.out.println("请检查该文件名是否正确，该文件是否存在，之后重启本程序。程序将在10秒钟后自动关闭");
			pause(10000);
			System.exit(0);
		}
		ServerIpAndPort[0] = p.getProperty("ServerIp");
		ServerIpAndPort[1] = p.getProperty("ServerPort");
		return ServerIpAndPort;
	}

	public static void pause(int milliSecond) // 程序暂停函数，参数是暂停的毫秒数
	{
		try
		{
			Thread.sleep(milliSecond);
		} catch (InterruptedException e)
		{
			System.out.println("程序暂停时出现位置异常程序，程序即将退出");
			System.exit(0);
		}
	}

	public static void setDateAndTime(String[] dateAndTime)
	{
		command1 = "cmd /c date " + dateAndTime[0] + "-" + dateAndTime[1] + "-"
				+ dateAndTime[2];
		command2 = "cmd /c time " + dateAndTime[3] + ":" + dateAndTime[4] + ":"
				+ dateAndTime[5] + "." + 60;
		Process p;
		Process q;
		try
		{
			p = Runtime.getRuntime().exec(command1);
			q = Runtime.getRuntime().exec(command2);
			p.waitFor();
			p.destroy();
			q.waitFor();
			q.destroy();
		} catch (Exception e)
		{
			System.out.println("设置本地系统的日期和时间时程序出现异常。");
			e.printStackTrace();
		}
	}
}