Synchronisation de l'heure NTP
Bonjour
Je ne sais pas si je suis au bon endroit.
je fais des recherches sur la Synchronisation de l'heure entre plusieurs Composant logicielle
j'ai trouvé qu'il faut utiliser le protocole NTP.
mais j'ai pas compris le principe de protocole
et comment je peux faire une implémentation en Java .
comme première pas j'ai commencer par voir l’exemple de Apache
voici les deux class de l'exemple :
La classe : NTPClient
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package examples.ntp;
import java.io.IOException;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.text.NumberFormat;
import org.apache.commons.net.ntp.NTPUDPClient;
import org.apache.commons.net.ntp.NtpUtils;
import org.apache.commons.net.ntp.NtpV3Packet;
import org.apache.commons.net.ntp.TimeInfo;
import org.apache.commons.net.ntp.TimeStamp;
public final class NTPClient
{
private static final NumberFormat numberFormat = new java.text.DecimalFormat("0.00");
/**
* Process <code>TimeInfo</code> object and print its details.
* @param info <code>TimeInfo</code> object.
*/
public static void processResponse(TimeInfo info)
{
NtpV3Packet message = info.getMessage();
int stratum = message.getStratum();
String refType;
if (stratum <= 0) {
refType = "(Unspecified or Unavailable)";
} else if (stratum == 1) {
refType = "(Primary Reference; e.g., GPS)"; // GPS, radio clock, etc.
} else {
refType = "(Secondary Reference; e.g. via NTP or SNTP)";
}
// stratum should be 0..15...
System.out.println(" Stratum: " + stratum + " " + refType);
int version = message.getVersion();
int li = message.getLeapIndicator();
System.out.println(" leap=" + li + ", version="
+ version + ", precision=" + message.getPrecision());
System.out.println(" mode: " + message.getModeName() + " (" + message.getMode() + ")");
int poll = message.getPoll();
// poll value typically btwn MINPOLL (4) and MAXPOLL (14)
System.out.println(" poll: " + (poll <= 0 ? 1 : (int) Math.pow(2, poll))
+ " seconds" + " (2 ** " + poll + ")");
double disp = message.getRootDispersionInMillisDouble();
System.out.println(" rootdelay=" + numberFormat.format(message.getRootDelayInMillisDouble())
+ ", rootdispersion(ms): " + numberFormat.format(disp));
int refId = message.getReferenceId();
String refAddr = NtpUtils.getHostAddress(refId);
String refName = null;
if (refId != 0) {
if (refAddr.equals("127.127.1.0")) {
refName = "LOCAL"; // This is the ref address for the Local Clock
} else if (stratum >= 2) {
// If reference id has 127.127 prefix then it uses its own reference clock
// defined in the form 127.127.clock-type.unit-num (e.g. 127.127.8.0 mode 5
// for GENERIC DCF77 AM; see refclock.htm from the NTP software distribution.
if (!refAddr.startsWith("127.127")) {
try {
InetAddress addr = InetAddress.getByName(refAddr);
String name = addr.getHostName();
if (name != null && !name.equals(refAddr)) {
refName = name;
}
} catch (UnknownHostException e) {
// some stratum-2 servers sync to ref clock device but fudge stratum level higher... (e.g. 2)
// ref not valid host maybe it's a reference clock name?
// otherwise just show the ref IP address.
refName = NtpUtils.getReferenceClock(message);
}
}
} else if (version >= 3 && (stratum == 0 || stratum == 1)) {
refName = NtpUtils.getReferenceClock(message);
// refname usually have at least 3 characters (e.g. GPS, WWV, LCL, etc.)
}
// otherwise give up on naming the beast...
}
if (refName != null && refName.length() > 1) {
refAddr += " (" + refName + ")";
}
System.out.println(" Reference Identifier:\t" + refAddr);
TimeStamp refNtpTime = message.getReferenceTimeStamp();
System.out.println(" Reference Timestamp:\t" + refNtpTime + " " + refNtpTime.toDateString());
// Originate Time is time request sent by client (t1)
TimeStamp origNtpTime = message.getOriginateTimeStamp();
System.out.println(" Originate Timestamp:\t" + origNtpTime + " " + origNtpTime.toDateString());
long destTime = info.getReturnTime();
// Receive Time is time request received by server (t2)
TimeStamp rcvNtpTime = message.getReceiveTimeStamp();
System.out.println(" Receive Timestamp:\t" + rcvNtpTime + " " + rcvNtpTime.toDateString());
// Transmit time is time reply sent by server (t3)
TimeStamp xmitNtpTime = message.getTransmitTimeStamp();
System.out.println(" Transmit Timestamp:\t" + xmitNtpTime + " " + xmitNtpTime.toDateString());
// Destination time is time reply received by client (t4)
TimeStamp destNtpTime = TimeStamp.getNtpTime(destTime);
System.out.println(" Destination Timestamp:\t" + destNtpTime + " " + destNtpTime.toDateString());
info.computeDetails(); // compute offset/delay if not already done
Long offsetValue = info.getOffset();
Long delayValue = info.getDelay();
String delay = (delayValue == null) ? "N/A" : delayValue.toString();
String offset = (offsetValue == null) ? "N/A" : offsetValue.toString();
System.out.println(" Roundtrip delay(ms)=" + delay
+ ", clock offset(ms)=" + offset); // offset in ms
}
public static void main(String[] args)
{
if (args.length == 0) {
System.err.println("Usage: NTPClient <hostname-or-address-list>");
System.exit(1);
}
NTPUDPClient client = new NTPUDPClient();
// We want to timeout if a response takes longer than 10 seconds
client.setDefaultTimeout(10000);
try {
client.open();
for (String arg : args)
{
System.out.println();
try {
InetAddress hostAddr = InetAddress.getByName(arg);
System.out.println("> " + hostAddr.getHostName() + "/" + hostAddr.getHostAddress());
TimeInfo info = client.getTime(hostAddr);
processResponse(info);
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
} catch (SocketException e) {
e.printStackTrace();
}
client.close();
}
} |
la classe : TimeClient
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package examples.ntp;
import java.io.IOException;
import java.net.InetAddress;
import org.apache.commons.net.time.TimeTCPClient;
import org.apache.commons.net.time.TimeUDPClient;
/***
* This is an example program demonstrating how to use the TimeTCPClient
* and TimeUDPClient classes.
* This program connects to the default time service port of a
* specified server, retrieves the time, and prints it to standard output.
* See <A HREF="ftp://ftp.rfc-editor.org/in-notes/rfc868.txt"> the spec </A>
* for details. The default is to use the TCP port. Use the -udp flag to
* use the UDP port.
* <p>
* Usage: TimeClient [-udp] <hostname>
* <p>
***/
public final class TimeClient
{
public static final void timeTCP(String host) throws IOException
{
TimeTCPClient client = new TimeTCPClient();
try {
// We want to timeout if a response takes longer than 60 seconds
client.setDefaultTimeout(60000);
client.connect(host);
System.out.println(client.getDate());
} finally {
client.disconnect();
}
}
public static final void timeUDP(String host) throws IOException
{
TimeUDPClient client = new TimeUDPClient();
// We want to timeout if a response takes longer than 60 seconds
client.setDefaultTimeout(60000);
client.open();
System.out.println(client.getDate(InetAddress.getByName(host)));
client.close();
}
public static void main(String[] args)
{
if (args.length == 1)
{
try
{
timeTCP(args[0]);
}
catch (IOException e)
{
e.printStackTrace();
System.exit(1);
}
}
else if (args.length == 2 && args[0].equals("-udp"))
{
try
{
timeUDP(args[1]);
}
catch (IOException e)
{
e.printStackTrace();
System.exit(1);
}
}
else
{
System.err.println("Usage: TimeClient [-udp] <hostname>");
System.exit(1);
}
}
} |
le problème c'est que je ne trouve Que des Classes Client : il n'y a pas de serveur ? dans NTP
vu que j'ai pas compris le principe je ne sais pas comment exécuter l’exemple
es que quelqu'un peut m'aider,pour compris le principe et faire ma propre Solution
j'ai trouvé sur google code une Solution
Les Classes De test
merci d’avance
merci pour n'import quelle reponse
