RMI Registry

rmacher · 15. Dez 2013

Hallo

Ich habe mehrere RMI Applikationen, die auf einem Server laufen sollten. Ich kann für jede Applikation jeweils eine Rmi-Registry Instanz (auf einem separaten Port) starten und dann funktioniert es. Jedoch würde ich gerne nur eine einzige RMI Registry Instanz laufen lassen und die RemoteObjects aus unterschiedlichen RMI-Applikationen bei der gleichen RMI Registry Instanz anmelden.

Ist das überhaupt möglich? Alle meine Versuche waren bis jetzt erfolgslos!

Konkret habe ich zwei kleine Test-Applikationen implementiert: die erste liefert Datum (als String) und die zweite die Zeit (als String) zurück.

Die erste Applikation (Date):

Java:

// Interface
package date.server;

import java.rmi.Remote;
import java.rmi.RemoteException;

public interface RmiDate extends Remote {
	String localDateAsString() throws RemoteException;
}

// Implementiertende Klasse 
package date.server;

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.text.SimpleDateFormat;
import java.util.Date;

public class RmiDateImpl extends UnicastRemoteObject implements RmiDate {

	private static final long serialVersionUID = 1L;

	public RmiDateImpl() throws RemoteException {

	}

	@Override
	public String localDateAsString() throws RemoteException {
		return new SimpleDateFormat("yyyy-MM-dd").format(new Date());
	}
}

// Server-Klasse 
package date.server;

import java.net.InetAddress;
import java.rmi.Naming;
import java.rmi.RMISecurityManager;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

import javax.swing.JOptionPane;

public class RmiDateServer {

	public static void main(String[] args) {

		int port = 0;
		String remoteObjectName = "dateRO";
		Registry reg = null;

		if (args.length < 1) {
			System.out
					.println("\nusage: java server.RmiDateServer rmiPortNummer");
			System.exit(0);
		} else {

			try {

				port = Integer.valueOf(args[0]);

				System.setProperty("java.security.policy", "rmi.policy");

				if (System.getSecurityManager() == null) {
					System.setSecurityManager(new RMISecurityManager());
				}

				try {
					reg = LocateRegistry.createRegistry(port);
				} catch (Exception e) {
					reg = LocateRegistry.getRegistry(port);
				}

				if (reg != null) {

					RmiDate obj = new RmiDateImpl();

					Naming.rebind(remoteObjectName, obj);

					JOptionPane
							.showMessageDialog(
									null,
									"RMI Date-Server ist bereit für Anfragen von Clients.\n\nServer herunterfahren?",
									"RMI TimeServer ["
											+ InetAddress.getLocalHost()
													.getHostAddress() + ":"
											+ port + "]",
									JOptionPane.QUESTION_MESSAGE);
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}

}

Die Policy-Datei ist (zum Testen) wie folgt:
[XML]
grant {
permission java.security.AllPermission;
};
[/XML]

Die zweite Applikation (Time):

Java:

// Interface
package time.server;

import java.rmi.Remote;
import java.rmi.RemoteException;

public interface RmiTime extends Remote {
	String localTimeAsString() throws RemoteException;
}


// Implementierende Klasse 
package time.server;

import java.io.Serializable;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.text.SimpleDateFormat;
import java.util.Date;

public class RmiTimeImpl extends UnicastRemoteObject implements RmiTime,
		Serializable {

	private static final long serialVersionUID = 1L;

	public RmiTimeImpl() throws RemoteException {

	}

	@Override
	public String localTimeAsString() throws RemoteException {
		return new SimpleDateFormat("hh:mm:ss:SSSS").format(new Date());
	}
}

// Server-Klasse:
package time.server;

import java.net.InetAddress;
import java.rmi.Naming;
import java.rmi.RMISecurityManager;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

import javax.swing.JOptionPane;

public class RmiTimeServer {

	public static void main(String[] args) {

		int port = 0;
		Registry reg = null;

		if (args.length < 1) {
			System.out
					.println("\nusage: java server.RmiTimeServer rmiPortNummer");
			System.exit(0);
		} else {
			try {
				port = Integer.valueOf(args[0]);

				System.setProperty("java.security.policy", "rmi.policy");

				if (System.getSecurityManager() == null) {
					System.setSecurityManager(new RMISecurityManager());
				}

				try {
					reg = LocateRegistry.createRegistry(port);
				} catch (Exception e) {
					reg = LocateRegistry.getRegistry(port);
				}

				if (reg != null) {

					RmiTime obj = new RmiTimeImpl();
					Naming.rebind("timeRO", obj);

					JOptionPane
							.showMessageDialog(
									null,
									"RMI Time-Server ist bereit für Anfragen von Clients.\n\nServer herunterfahren?",
									"RMI TimeServer ["
											+ InetAddress.getLocalHost()
													.getHostAddress() + ":"
											+ port + "]",
									JOptionPane.QUESTION_MESSAGE);
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}

}

Die rmi.policy Datei ist wie bei der ersten Applikation (AllPermission) und steht auch zur Verfügung.

Ich kann eine (beliebige) Applikation starten, jedoch wenn ich die zweite Applikation starte (mit der gleichen RMI Port-Nummer), wird die Ausnahme geworfen.

Hier die Ausnahme:

Java:

java.rmi.ServerException: RemoteException occurred in server thread; nested exception is: 
	java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
	java.lang.ClassNotFoundException: time.server.RmiTime
	at sun.rmi.server.UnicastServerRef.oldDispatch(Unknown Source)
	at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
	at sun.rmi.transport.Transport$1.run(Unknown Source)
	at sun.rmi.transport.Transport$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Unknown Source)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
	at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
	at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
	at sun.rmi.server.UnicastRef.invoke(Unknown Source)
	at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
	at java.rmi.Naming.rebind(Unknown Source)
	at time.server.RmiTimeServer.main(RmiTimeServer.java:41)
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
	java.lang.ClassNotFoundException: time.server.RmiTime
	at sun.rmi.registry.RegistryImpl_Skel.dispatch(Unknown Source)
	at sun.rmi.server.UnicastServerRef.oldDispatch(Unknown Source)
	at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
	at sun.rmi.transport.Transport$1.run(Unknown Source)
	at sun.rmi.transport.Transport$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Unknown Source)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: time.server.RmiTime
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.rmi.server.LoaderHandler$Loader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Unknown Source)
	at sun.rmi.server.LoaderHandler.loadClassForName(Unknown Source)
	at sun.rmi.server.LoaderHandler.loadProxyInterfaces(Unknown Source)
	at sun.rmi.server.LoaderHandler.loadProxyClass(Unknown Source)
	at sun.rmi.server.LoaderHandler.loadProxyClass(Unknown Source)
	at java.rmi.server.RMIClassLoader$2.loadProxyClass(Unknown Source)
	at java.rmi.server.RMIClassLoader.loadProxyClass(Unknown Source)
	at sun.rmi.server.MarshalInputStream.resolveProxyClass(Unknown Source)
	at java.io.ObjectInputStream.readProxyDesc(Unknown Source)
	at java.io.ObjectInputStream.readClassDesc(Unknown Source)
	at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
	at java.io.ObjectInputStream.readObject0(Unknown Source)
	at java.io.ObjectInputStream.readObject(Unknown Source)
	... 13 more

Habe auch versucht, RMI Registry aus dem Commandprompt (als separaten Prozess) zu starten, jedoch kommt es gleich.

C:\Temp>rmiregistry 1099

Wenn ich anschliessend z.B. die Date-Applikation starten versuche, bekomme ich wieder das Problem:

Java:

java.rmi.ServerException: RemoteException occurred in server thread; nested exception is: 
	java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
	java.lang.ClassNotFoundException: date.server.RmiDate
	at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:419)
	at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:267)
	at sun.rmi.transport.Transport$1.run(Transport.java:177)
	at sun.rmi.transport.Transport$1.run(Transport.java:174)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:556)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:811)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:670)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:724)
	at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
	at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
	at sun.rmi.server.UnicastRef.invoke(Unknown Source)
	at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
	at java.rmi.Naming.rebind(Unknown Source)
	at date.server.RmiDateServer.main(RmiDateServer.java:45)
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
	java.lang.ClassNotFoundException: date.server.RmiDate
	at sun.rmi.registry.RegistryImpl_Skel.dispatch(Unknown Source)
	at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:409)
	at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:267)
	at sun.rmi.transport.Transport$1.run(Transport.java:177)
	at sun.rmi.transport.Transport$1.run(Transport.java:174)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:556)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:811)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:670)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:724)
Caused by: java.lang.ClassNotFoundException: date.server.RmiDate
	at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.rmi.server.LoaderHandler$Loader.loadClass(LoaderHandler.java:1206)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:270)
	at sun.rmi.server.LoaderHandler.loadClassForName(LoaderHandler.java:1219)
	at sun.rmi.server.LoaderHandler.loadProxyInterfaces(LoaderHandler.java:729)
	at sun.rmi.server.LoaderHandler.loadProxyClass(LoaderHandler.java:673)
	at sun.rmi.server.LoaderHandler.loadProxyClass(LoaderHandler.java:610)
	at java.rmi.server.RMIClassLoader$2.loadProxyClass(RMIClassLoader.java:646)
	at java.rmi.server.RMIClassLoader.loadProxyClass(RMIClassLoader.java:311)
	at sun.rmi.server.MarshalInputStream.resolveProxyClass(MarshalInputStream.java:255)
	at java.io.ObjectInputStream.readProxyDesc(ObjectInputStream.java:1556)
	at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1512)
	at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1769)
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348)
	at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
	... 13 more

Meine Frage noch einmal:
Ist so etwas überhaupt möglich? Und falls ja, was mache ich hier falsch?

Ich habe hier den vollständigen Code angegeben und hoffe, dass mir jemand helfen kann. Besten Dank für jeden Hinweis.

P.S.
Habe auch ohne Security-Manager versucht, jedoch das Problem bleibt weiterhin bestehen.

rmacher · 15. Dez 2013

Habe die Lösung gefunden:

Enhancements in JDK 7

	Titel	Forum	Antworten	Datum
C	RMI Bereits bestehende Registry nutzen	Netzwerkprogrammierung	2	8. Jul 2012
T	RMI Registry nicht mit beenden.	Netzwerkprogrammierung	6	27. Aug 2010
H	RMI Connection refused bei RMI-Registry	Netzwerkprogrammierung	10	28. Mai 2010
K	Getrennte Rechner für RMI-Server/RMI-Registry, bzw. Alternativen?	Netzwerkprogrammierung	5	12. Feb 2010
	RMI - eigene Registry (no security manager: RMI class loader disabled)	Netzwerkprogrammierung	6	14. Sep 2009
T	RMI Registry nachsehen was drinnen ist	Netzwerkprogrammierung	2	15. Feb 2009
K	Registry	Netzwerkprogrammierung	4	9. Jan 2008
R	Registry RMI starten ?	Netzwerkprogrammierung	7	16. Sep 2007
F	Problem mit RMI Registry	Netzwerkprogrammierung	4	28. Mai 2007
M	RMI: Registry.bind oder Naming.bind?	Netzwerkprogrammierung	2	12. Apr 2007
E	Mit Java Registry ändern?	Netzwerkprogrammierung	7	9. Mrz 2004

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