Is there a way to connect to your email inbox in java (using netbeans IDE) without the use of JavaMail API? I have been searching for a way to do it without the use of that API as I am trying to construct a program which reads my email and stores them into a database using sql server. is there a way?
You can use Socket classes.
Send message directly.
If you want to do this the hard way, you can write e.g. a POP3 client in Java yourself.
Use Socket, connect to the right host and port (port is usually 110) and start issuing POP3 commands.
http://www.ietf.org/rfc/rfc1939.txt
http://docs.oracle.com/javase/7/docs/api/java/net/Socket.html
Why not use JavaMail? There are other libraries available, such as ChilKat's - or you could talk POP3/IMAP directly, you know open a socket on port 110/143 and issue commands and read the responses (which is what the libraries will do for you).
If you have to provide a single JAR file, you can merge the JavaMail classes (and dependencies) with your own code, or - depending on your target infrastructure - a WAR or EAR might be more appropriate.
Cheers,
I started with requirement of reading and writing files in from/in a directory on a remote Ubuntu machine.
First, I wrote a Java program that could read,write files from a shared folder on a remote Windows machine i.e on a LAN. Here, something like this works on my(local) Windows machine :
File inputFile = new File(
"\\172.17.89.76\EBook PDF");/*ignore the syntax errors, the loc is just for the idea*/
Now when I consider a remote Ubuntu machine, obviously I cannot do something like this as the machine is not on the LAN(I'm not sure if that can be done even if it is on the LAN!). Hence, I tried following approaches :
Using Jsch, establishing the trust between two machines(local - remote Linux , remote Linux - remote Linux) and file writing using sftp.(done)
Running sockets on the two machines - one sender, one receiver(both Java)(done)
Attempting to achieve I/O alike the code snippet for Windows (LAN) machines(not achieved)
While doing all these, I had many queries, read many posts etc. and I felt that I'm missing something on the fundamentals :
Some sort of trust-building(between two machines) utility will be required to achieve IO. But finally, I want to write a code like the snippet given, irrespective of the machines, network etc.
The Jsch solution and the others suggested(usage of http, ftp etc. over URL) finally are using some services that are running on the remote machine. In other words, it is NOT THAT Java IO is being used to access the remote file system - this doesn't appeal to me as I'm relying on services rather than using good-old I/O.
Samba, SSHFS too popped onto the scene, only to add to my confusion. But I don't see them as the solutions to my objective !
To reiterate, I want to write a code using Java I/O(either plain or nio, both are fine) which simply can read, write remote files without using services over protocols like ftp, http etc. or socket sender-receiver model. Is my expectation valid?
If not, why and what is the best I can do to read/write remote files
using Java?
If yes, how to achieve the same !
P.S : Please comment in case I need to elaborate to pose my question accurately !
To answer your question - No, your expectation isn't valid.
Retrieving files from a remote server is inherently reliant on the services running on that server. To retrieve a file from a remote server, the remote server needs to be expecting your request for a file.
The cases you listed in your question (using jsch and sftp, using a sender and receiver Java sockets) that you have achieved already, are essentially the same as this:
File inputFile = new File(
"\\172.17.89.76\EBook PDF");
The only difference is that Java is using the native os's built in support for reading from a windows style share. The remote windows machine has a sharing service running on it (just like Samba on linux, or a java socket program) waiting for your request.
From the Java API docs on File (http://docs.oracle.com/javase/6/docs/api/java/io/File.html)
The canonical pathname of a file that resides on some other machine and is accessed via a remote-filesystem protocol such as SMB or NFS ...
So essentially "Good old Java I/O" is more or less just a wrapper over some common protocols.
To answer the second part of your question (what is the best I can do to read/write remote files using Java?), that depends on what remote system you are accessing and, more importantly, what services are running on it.
In the case of your target remote machine being an Ubuntu machine, I would say the best alternative would be to use Jsch. If your target machine can be either a windows machine or a linux machine, I would probably go for running Java sockets on the two machines (obviously dependant on whether you have access to installing your app on the remote machine).
Generally speaking, go with the common lowest denominator between your target systems (in terms of file sharing protocols).
If you want to access a filesystem on a remote computer, then this computer has to make his filesystem available with a service. Such a service is typically a background job, which handles incoming requests and returns a response, e.g. for authentication, authorization, reading and writing. The specification of the request/response pattern is called a protocol. Well known protocols are SMB (or SAMBA) on Windows or NFS on UNIX/LINUX. To access such a remote service you mount the remote filesystem on the level of the operating system and make it available locally as a drive on Windows or as mount point on UNIX.
Then you can access the remote file system from your Java program like any local file system.
Of course it is also possible to write your own file service provider (with your own protocol layer) and run it on the remote machine. As transport layer for such an endeavor sockets (TCP/IP) can be used. Another good transport layer would be the http protocol, e.g. with a restful service or something based on WebDav.
We used sshfs. You can add to /etc/fstab the line:
sshfs#user#remoteAddress:remoteDir /mnt/ssh fuse defaults 0 0
and then mount /mnt/ssh
I think RMI might be the solution, you could set up a server an RMI server on the machine you want to connect to, and use your machine a the client.
I would give the client a path to the file this will be sent to the server, the server could then read in the file as bytes and sent the file back to the client.
The question us also related to linux but solution is needed for Java. So I have a data directory
/somedir/data
on linux server
servername
I can ssh to the server and do anything I want only from deployment machine (due public/private keys in place). But there's a Java process that should read files from that directory. How can I force it read that files? I was trying to use File("//servername/somedir/data") with no success. Any help would be appreciated.
You must share the file using one of the network file services.
For example:
NFS (check with showmount -e);
Samba (check with smbclient -L);
AFS;
HTTP/FTP (check first if there a HTTP/FTP-server on the host).
You can also access this file using SSH (you say that you have SSH connection to the host, that means that SSH is accessible anyway).
If you want to connect to the SSH server from Java program,
you can use (for example) JSch for that.
Example of JSch usage is here.
I am trying to use RMI to open notepad in the remote system.
Is it possible to do that using RMI??
Or do I have to use SSH ??
Comparing RMI with SSH is a bit like comparing apples with oranges. RMI is more of a general purpose API for performing requests over the network, while SSH is a program used to establish a secure shell connection over which you can send shell commands.
To open Notepad on a remote host, you can use either RMI or SSH since both are capable of communicating over the network.
In either case, you'll need a server on the receiving end, that handles your commands and opens Notepad for you. If you use SSH, this will be readily available to you, in the form of an sshd daemon. In case you go for RMI I don't know of any predefined server implementation. I would recommend you to write up your own server serving your particular requests.
I need to access the remote MYsql database from java which can be accessed only through ssh
SSH tunneling works perfectly fine for my application as most of the linux systems come with built in ssh client.
java.sql.Connection extension for SSH
what if i need to access the database from windows system, by using putty or some other ssh client.
can we do ssh tunneling in windows system as if in ubuntu systems.:)
Yes, you can, see Using PuTTY under Windows to create an SSH tunnel to your NetManager. Basically you need to set up a tunnel to the mysql port and then you can use the JDBC as natural without it being aware of the tunneling happening
There are plenty of SSH clients for java:
Apache MINA SSH
Java Secure Channel (JSCH)
github.com/shikhar/sshj
http://orion-ssh2.sourceforge.net/
Probably you can take a look and see who is going to work for you, but I think jsch could solve your probelm. See examples here