Java Language Remote Method Invocation (RMI) Simple RMI example with Client and Server implementation
Example
This is a simple RMI example with five Java classes and two packages, server and client.
Server Package
PersonListInterface.java
public interface PersonListInterface extends Remote
{
/**
* This interface is used by both client and server
* @return List of Persons
* @throws RemoteException
*/
ArrayList<String> getPersonList() throws RemoteException;
}
PersonListImplementation.java
public class PersonListImplementation
extends UnicastRemoteObject
implements PersonListInterface
{
private static final long serialVersionUID = 1L;
// standard constructor needs to be available
public PersonListImplementation() throws RemoteException
{}
/**
* Implementation of "PersonListInterface"
* @throws RemoteException
*/
@Override
public ArrayList<String> getPersonList() throws RemoteException
{
ArrayList<String> personList = new ArrayList<String>();
personList.add("Peter Pan");
personList.add("Pippi Langstrumpf");
// add your name here :)
return personList;
}
}
Server.java
public class Server {
/**
* Register servicer to the known public methods
*/
private static void createServer() {
try {
// Register registry with standard port 1099
LocateRegistry.createRegistry(Registry.REGISTRY_PORT);
System.out.println("Server : Registry created.");
// Register PersonList to registry
Naming.rebind("PersonList", new PersonListImplementation());
System.out.println("Server : PersonList registered");
} catch (final IOException e) {
e.printStackTrace();
}
}
public static void main(final String[] args) {
createServer();
}
}
Client package
PersonListLocal.java
public class PersonListLocal {
private static PersonListLocal instance;
private PersonListInterface personList;
/**
* Create a singleton instance
*/
private PersonListLocal() {
try {
// Lookup to the local running server with port 1099
final Registry registry = LocateRegistry.getRegistry("localhost",
Registry.REGISTRY_PORT);
// Lookup to the registered "PersonList"
personList = (PersonListInterface) registry.lookup("PersonList");
} catch (final RemoteException e) {
e.printStackTrace();
} catch (final NotBoundException e) {
e.printStackTrace();
}
}
public static PersonListLocal getInstance() {
if (instance == null) {
instance = new PersonListLocal();
}
return instance;
}
/**
* Returns the servers PersonList
*/
public ArrayList<String> getPersonList() {
if (instance != null) {
try {
return personList.getPersonList();
} catch (final RemoteException e) {
e.printStackTrace();
}
}
return new ArrayList<>();
}
}
PersonTest.java
public class PersonTest
{
public static void main(String[] args)
{
// get (local) PersonList
ArrayList<String> personList = PersonListLocal.getInstance().getPersonList();
// print all persons
for(String person : personList)
{
System.out.println(person);
}
}
}
Test your application
- Start main method of Server.java. Output:
Server : Registry created.
Server : PersonList registered
- Start main method of PersonTest.java. Output:
Peter Pan
Pippi Langstrumpf
