校时

需要管理员权限

package com.siqi;

import java.io.PrintStream;

import java.net.URL;

import java.net.URLConnection;

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Locale;

import java.util.TimeZone;

import java.util.TimerTask;

public class OSTime extends TimerTask{

  public void run(){

    try{

      URLConnection conn = new URL("http://www.baidu.com")

        .openConnection();

      String dateStr = conn.getHeaderField("Date");

      System.out.println("获取到的服务器时间：" + dateStr);

      DateFormat httpDateFormat = new SimpleDateFormat(

        "E, dd MMM yyyy HH:mm:ss z", Locale.US);

      httpDateFormat.setTimeZone(TimeZone.getTimeZone("GMT+8"));

      Date date = httpDateFormat.parse(dateStr);

      String currDate = new SimpleDateFormat("yyy-MM-dd").format(date);

      String currTime = new SimpleDateFormat("HH:mm:ss").format(date);

      setTime(currDate, currTime);

    } catch (Exception e) {

      e.printStackTrace();

    }

  }

  public static void setTime(String date, String time){

    String osName = System.getProperty("os.name");

    String cmd = "";

    try{

      Process execTime;

      Process execDate;

      Process execTime;

      if (osName.matches("^(?i)Windows.*$")){  //windows系统

        cmd = " cmd /c date " + date;

        Process execDate = Runtime.getRuntime().exec(cmd);

        cmd = "  cmd /c time " + time;

        execTime = Runtime.getRuntime().exec(cmd);

      }

      else { //linux系统

        cmd = "  date -s " + date;

        execDate = Runtime.getRuntime().exec(cmd);

        cmd = "  date -s " + time;

        execTime = Runtime.getRuntime().exec(cmd);

      }

      if (execDate.waitFor() == 0)

        System.out.println("设置系统日期成功：" + date);

      else

        System.out.println("设置系统日期成功：" + date);

      if (execTime.waitFor() == 0)

        System.out.println("设置系统时间成功：" + time);

      else

        System.out.println("设置系统时间失败：" + time);

    } catch (Exception e) {

      e.printStackTrace();

    }

  }

}

package com.siqi;

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStream;

import java.io.PrintStream;

import java.util.Properties;

import java.util.Timer;

import javax.script.ScriptEngine;

import javax.script.ScriptEngineManager;

public class Start{

  public static void main(String[] args){

    try{

      InputStream in = new FileInputStream(new File("config.properties"));

      Properties property = new Properties();

      property.load(in);

      String cycle = property.getProperty("cycle");

      System.out.println(cycle);

      ScriptEngineManager manager = new ScriptEngineManager();

      ScriptEngine engine = manager.getEngineByName("js");

      String result = engine.eval(cycle).toString();

      double cycleDouble = Double.parseDouble(result);

      int cycleInt = (int)cycleDouble;

      System.out.println("定时器执行周期为(单位ms)  " + cycleInt);

      OSTime ostime = new OSTime();

      Timer timer = new Timer();

      timer.schedule(ostime, 1000L, cycleInt);

    }

    catch (Exception e) {

      e.printStackTrace();

    }

  }

}