获得网络时间.docx

显示图片 | 并排多个listView 2011-03-27获得网络时间 博客分类： androidJNIOSIDEAHTML.net转自：/javadetails/java-0589.htmlWe connect to a publicly accessible time server on the internet and parse the result.List of available time servers :/service/time-servers.htmlNOTE : All users should ensure that their software NEVER queries a server more frequently than once every 4 seconds. Systems that exceed this rate will be refused service. In extreme cases, systems that exceed this limit may be considered as attempting a denial-of-service attack.import java.io.*;import java.text.*;import java.util.*;import .*;public final class DateUtils / NIST, Boulder, Colorado () public static final String ATOMICTIME_SERVER=01:13; / NIST, Gaithersburg, Maryland () / public static final String ATOMICTIME_SERVER=8:13; public final static GregorianCalendar getAtomicTime() throws IOException BufferedReader in = null; try URLConnection conn = new URL(ATOMICTIME_SERVER).openConnection(); in = new BufferedReader (new InputStreamReader(conn.getInputStream(); String atomicTime; while (true) if ( (atomicTime = in.readLine().indexOf(*) -1) break; System.out.println(DEBUG : + atomicTime); String fields = atomicTime.split( ); GregorianCalendar calendar = new GregorianCalendar(); String date = fields1.split(-); calendar.set(Calendar.YEAR, 2000 + Integer.parseInt(date0); calendar.set(Calendar.MONTH, Integer.parseInt(date1)-1); calendar.set(Calendar.DATE, Integer.parseInt(date2); / deals with the timezone and the daylight-saving-time TimeZone tz = TimeZone.getDefault(); int gmt = (tz.getRawOffset() + tz.getDSTSavings() / 3600000; System.out.println(DEBUG : + gmt); String time = fields2.split(:); calendar.set(Calendar.HOUR_OF_DAY, Integer.parseInt(time0) + gmt); calendar.set(Calendar.MINUTE, Integer.parseInt(time1); calendar.set(Calendar.SECOND, Integer.parseInt(time2); return calendar; catch (IOException e) throw e; finally if (in != null) in.close(); public static void main(String args) throws IOException SimpleDateFormat sdf = new SimpleDateFormat(yyyy-MM-dd HH:mm:ss); System.out.println(Atomic time : + sdf.format(DateUtils.getAtomicTime().getTime(); /* ref : /doc-tour/atomic_clock.html 49825 95-04-18 22:24:11 50 0 0 50.0 UTC(NIST) * | | | | | | | | | These are the last + | | | | | | | | five digits of the | | | | | | | | Modified Julian Date | | | | | | | | | | | | | | | | Year, Month and Day -+ | | | | | | | | | | | | | | Hour, minute, and second of the -+ | | | | | | current UTC at Greenwich. | | | | | | | | | | | | DST - Daylight Savings Time code -+ | | | | | 00 means standard time(ST), 50 means DST | | | | | 99 to 51 = Now on ST, goto DST when local | | | | | time is 2:00am, and the count is 51. | | | | | 49 to 01 = Now on DST, goto ST when local | | | | | time is 2:00am, and the count is 01. | | | | | | | | | | Leap second flag is set to 1 when -+ | | | | a leap second will be added on the last | | | | day of the current UTC month. A value of | | | | 2 indicates the removal of a leap second. | | | | | | | | Health Flag. The normal value of this -+ | | | flag is 0. Positive values mean there may | | | be an error with the transmitted time. | | | | | | The number of milliseconds ACTS is advancing -+ | | the time stamp, to account for network lag. | | | | Coordinated Universal Time from the National -+ | Institute of Standards & Technology. | | The instant the * appears, is the exact time. -+ */ thanks to