sivaramaiah - Record 2

Record 2:File transfer:
Create a server that asks for a password, then opens a file and sends the file over the network connection. Create a client that connects to this server, gives the appropriate password, then captures and saves the file.

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Program 1: Interface program filet.java

import java.rmi.*;

public interface fileT extends Remote

{

public String getfilepwd(String pwd) throws RemoteException;

}

Program 2: Implementation program fileTImp.java

import java.rmi.*;

import java.rmi.server.*;

import java.io.*;

public class fileTImp extends UnicastRemoteObject implements fileT

{

private String fileurl;

public fileTImp(String fname) throws RemoteException

{

fileurl = fname;

}

public String getfilepwd(String pwd) throws RemoteException

{

if(pwd.compareTo("62075064")!=0) return "Invalid Password";

byte buffer[] = new byte[2056];

try

{

FileInputStream fis = new FileInputStream(fileurl);

int bytes = fis.read(buffer,0,2056);

try

{

String str = new String(buffer,0,bytes,"Default");

return(str);

}

catch(Exception e)

{ System.out.println("Error, maybe string error :"+e);

}

catch(Exception e)

{ System.out.println("Error at fileTImp : "+e);

}

return "File not found";

}

Program 3: Server program fileTServer.java

import java.rmi.*;

import java.rmi.server.*;

public class fileTServer

{

public static void main(String[] args)

{

try

{

System.out.print("Constructing Server Implementation...");

fileTImp fileT1 = new fileTImp("secret.txt");

Naming.rebind("secretfile",fileT1);

System.out.print("Done!nWaiting for Invocations from client...n");

}

catch(Exception e)

{ System.out.print("Error at fileTServer : "+e);

}

Program 4: Client program fileTClient.java

import java.rmi.*;

import java.rmi.server.*;

import java.io.*;

public class fileTClient

{

public static void main(String[] args)

{

try

{

System.out.print("Enter Password : ");

DataInputStream dis = new DataInputStream(System.in);

String password = dis.readLine();

System.out.print("Naming.lookup for Bindings...");

fileT file1 = (fileT) Naming.lookup("secretfile");

System.out.print("Done!n");

System.out.print("Info from Server: n"+file1.getfilepwd(password));

}

catch(Exception e)

{ System.out.print("Error at fileTClient : "+e);

}

Program 5: Secrete file secrete.txt

!!! Congratulations !!!

You opened the file which requires secret password.

RPC = Remote Procedure Call

RMI = Remote Method Invocation

CORBA = Common Object Broker Architecture

ORB = Object Request Brokarage

IIOP = Internet Inter ORB Protocol

JDBC = Java DataBase Connectivity

Java IDL = Java Interface Definition Language

Author: Siva Ramaiah

E-mail: siva_sriramula@yahoo.com

Created:10:43 AM 11/12/2008

Program 6: Show Bindings showBingings.java

import java.rmi.*;

import java.rmi.server.*;

public class showBindings

{

public static void main(String[] args)

{

try

{

String[] bindings = Naming.list("");

for(int i=0;i<bindings.length;i++)

System.out.println("Binding ["+(i+1)+"] => "+bindings[i]);

}

catch(Exception e)

{ System.out.println("Error in showBindings : "+e.toString()); }

}

Program 7: clinet.policy clinet.policy

grant

{

permission java.net.SocketPermission

"*:1024-65335","connect";

};

How to run the program

1. compile all java files

javac *.java

2. use RMICompiler to create stubs & skeletons of Implementations

rmic fileTImp

3. run rmiregistry

start rmiregistry

4. create policy file with following contents

client.policy

~~~~~~~~~~~~~

grant

{

permission java.net.SocketPermission

"*:1024-65335","connect";

};

5. run server

java fileTServer

6. run client with policy created in step 4.

java -Djava.security.policy=client.policy fileTClient