Download Files From Various Servers Using RMI

To Create  a program to download files from various servers using RMI

•   Define the interface.
• Interface must extend Remote
•   All methods must throw an exception Remote Exception individually
• Implement the interface.
•  Create a server program.
• Create a Client Program.
•  Generate stubs and skeletons using rmic tool.
• Start the server.
•   Start the client.
• Once the process is over stop the client and server respectively.

fileinterface.java

// Comment
import java.rmi.*;
public interface fileinterface extends Remote
{
public byte[]download file(String s)throws RemoteException;
}

fileimplement.java

// Comment
import java.io.*;
import java.rmi.*;
import java.rmi.server.*;
public class fileimplement extends UnicastRemoteObject implements fileinterface
{
private String name;
public fileimplement(String s)throws RemoteException
{
super();
name=s;
}
public byte[]downloadfile(String fn)                                       
{
try
{
File fi=new File(fn);
byte buf[]=new byte[(int)fi.length()];
BufferedInputStream bis=new BufferedInputStream(new FileInputStream(fn));
bis.read(buf ,0,buf.length);                                                                                                                                                                                                                                            
bis.close();
return(buf);
}
catch(Exception ee)
{
System.out.println("Error:"+ee.getMessage());
ee.printStackTrace();
return(null) ;
}}
}

fileserver.java

// Comment
import java.rmi.*;
import java.io.*;
import java.net.*;
import java.rmi.registry.*;
public class fileserver
{
public static void main(String arg[])
{
try
{
fileimplement fi=new fileimplement("fileserver");
Registry reg=LocateRegistry.createRegistry(5000);
reg.rebind("fileserver",fi);
System.out.println("server is ready");
}
catch(Exception e)
{
System.out.println(" "+e.getMessage());
e.printStackTrace();
}
}
}

fileclient.java

import java.net.*;
import java.rmi.*;
import java.io.*;
public class fileclient
{
    public static void main(String[] args)   
 {
       try{
                //  InetAddress addr=InetAddress.getLocalHost();
          // String address=addr.toString().substring(addr.toString().indexOf("/")+1);
         //  String url="rmi://"+ address + "/fileserver";
           fileinterface f1=(fileinterface)Naming.lookup("rmi://localhost:5000/fileserver");
           byte[] data=f1.downloadfile(args[0]);
           File ff=new File("f1.txt");
           BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(ff.getName()));
           bos.write(data,0,data.length);
           bos.flush();
           bos.close();}
           catch(Exception e){
                      System.out.println(" "+e.getMessage());
           e.printStackTrace();           }
}
}
 

Output Screen