Read file from URL and save to FTP

**nitinmukesh** · 07-21-2008, 02:02 PM

Hi,

I have worked in java few years back, now I am out of touch. My friend asked me to create an applet program for him which he can use to download a file from remote location to his ftp server.

For e.g.
File

Saved to

I was searching for the classes which I can use to achieve this functionality.

To save to FTP

{code}
URL url = new URL("");
URLConnection urlconnection = url.openConnection();
long l = urlconnection.getContentLength();
OutputStream outputstream = null;
outputstream = urlconnection.getOutputStream();
{code}

Using the above code I can get the outputstream to which I can write.

I am now stuck here, have some doubts.

What all classes should I use to read a file like

I know I can use URL to open connection to URLS and then streams to read the url.
I am interested in knowing the class which I should use to read any type of file. File can be zip/avi/rar or anything else.
What all method of the class should I use to read the file which will support all type of files.

Which classes should I use to write the files. The files are going to be huge in terms of size.

I have searched everywhere but every place different classes are used.

Any help is appreciated.

**nitinmukesh** · 07-21-2008, 02:04 PM

Since I can't post URL's attached is the message

**Norm** · 07-21-2008, 03:59 PM

You could use InputStream and OutputStream to read and write bytes.
Write a small test program that reads and writes a file (copies) to verify you are using the classes/methods correctly before using them in you program. You can use a URL to reference the files by using the file:// protocol.

**nitinmukesh** · 07-21-2008, 05:29 PM

Ok now I have started coding but facing a problem.

PHP Code:

try {

	URL url = new URL("url_to_file/test.txt");
	URLConnection urlconnection = url.openConnection();
	long l = urlconnection.getContentLength();
	fTextArea.append("Content Length = " + l);
	BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
	String line;
	while ((line = in.readLine()) != null)
	{
		fTextArea.append("\n"+line);
	}
	in.close();

} catch (Exception e) {
   fTextArea.append(e);
   return;
}

When I run this code locally it works fine but when run in browser it shows security exception

java.security.AccessControlException: access denied (java.net.SocketPermission site:80 connect,resolve)

What should I do to resolve this error. Sorry for being such a noob but do not have much info about this.

**Norm** · 07-21-2008, 10:25 PM

Here's some code from one of my applets that sends a request to a server for a file and reads the response:

Java Code:

  
        URL u = null;
        BufferedReader in;
 .....
                // We're in an applet - go to server for the file
//                u = new URL(getCodeBase() + CGI_DIR + "/GetFile.pl?" + fn);
                u = new URL(getCodeBase() + fn + (addSfx ==  null ? "" : addSfx));   // do HTTP GET directly
                URLConnection uc = u.openConnection();
                in = new BufferedReader(new InputStreamReader(
                                uc.getInputStream()));

The applet can only connect to the server it came from. In the above that address is given by getCodeBase().

It is possible to give an applet permission to connect via the policytool program. It creates an entry in the .java.policy file giving permissions for connect and resolve.
Also it might be possible by signing the jar file the applet is in.