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java.net.UnknownHostException: C

Posted on 2004-04-10
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Last Modified: 2011-09-20
I am getting java.net.UnknownHostException: C on Windows XP, when trying to open a html document using JEditorPane. Below is the code. Same code works fine on Windows 2000 though.


import java.awt.Dimension ;
import java.awt.Toolkit;

import javax.swing.JEditorPane;
import javax.swing.JScrollPane;
import javax.swing.JDialog;

import java.net.URL;

import java.io.IOException;


public class TestHelpDoc {


      public static void main(String args[]) {

            try {
                  JEditorPane pane = new JEditorPane("file://C:/userDocs/ui/logonUserDoc.htm");
                  JScrollPane scroller = new JScrollPane();
                  scroller.getViewport().add(pane);
                  JDialog dialog = new JDialog();
                  dialog.getContentPane().add(scroller);
                  dialog.pack();
                    // initialize screen display size location
                  Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
                  double displayWidth = screenSize.getWidth() - (10 * 2);
                  double displayHeight = screenSize.getHeight() - (60 * 4);
                  dialog.setBounds(10, 60,(int) displayWidth, (int) displayHeight);
                  dialog.setVisible(true);
            }

            catch (Exception e) {
                  e.printStackTrace();
            }


      }
}

and the StackTrace:
java.net.UnknownHostException: C
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:153)
        at java.net.Socket.connect(Socket.java:452)
        at java.net.Socket.connect(Socket.java:402)
        at sun.net.NetworkClient.doConnect(NetworkClient.java:139)
        at sun.net.NetworkClient.openServer(NetworkClient.java:118)
        at sun.net.ftp.FtpClient.openServer(FtpClient.java:423)
        at sun.net.ftp.FtpClient.<init>(FtpClient.java:692)
        at sun.net.www.protocol.ftp.FtpURLConnection.connect(FtpURLConnection.ja
va:175)
        at sun.net.www.protocol.ftp.FtpURLConnection.getInputStream(FtpURLConnec
tion.java:257)
        at javax.swing.JEditorPane.getStream(JEditorPane.java:704)
        at javax.swing.JEditorPane.setPage(JEditorPane.java:392)
        at javax.swing.JEditorPane.setPage(JEditorPane.java:775)
        at javax.swing.JEditorPane.<init>(JEditorPane.java:249)
     

Regards,
0
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Question by:allahabad
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9 Comments
 
LVL 14

Assisted Solution

by:Tommy Braas
Tommy Braas earned 50 total points
ID: 10799613
Change the instantiation of the JEditorPane to (adding another '/'):
 
    JEditorPane pane = new JEditorPane("file:///C:/userDocs/ui/logonUserDoc.htm");
 
0
 
LVL 92

Expert Comment

by:objects
ID: 10799669

 JEditorPane pane = new JEditorPane("file:///C|/userDocs/ui/logonUserDoc.htm");
0
 
LVL 3

Author Comment

by:allahabad
ID: 10799684
Thanks orangehead911 and objects.

Yes, it works on Windows 2000 and XP.

Why is it different for file protocol; URL syntax(protocol://resourseLoation) wise, compare to http or RMI or any other protocol.
 


Regards,
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LVL 92

Expert Comment

by:objects
ID: 10799703
> Why is it different for file protocol

its not.

protocol is "file", host is blank, filename is "C|/userDocs/ui/logonUserDoc.htm"
0
 
LVL 3

Author Comment

by:allahabad
ID: 10799771
Hi objects,

It's nice to see your response.

I am still not clear no this.

There is 3 "///" (file:///) for file protocol instead of  2 "//" as we write after the protocol like "http://hostname/file".

So, one extra "/" is to mention host which is blank ?.

Regards,
0
 
LVL 92

Accepted Solution

by:
objects earned 200 total points
ID: 10799778
> There is 3 "///" (file:///) for file protocol instead of  2 "//"

no 2 after the protocol, and one after the (nonexistent) host.

> as we write after the protocol like "http://hostname/file".

if there was no host it would look like:
http:///file

> So, one extra "/" is to mention host which is blank ?

that is correct
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LVL 86

Expert Comment

by:CEHJ
ID: 10808653
JEditorPane pane = new JEditorPane("file:/C:/userDocs/ui/logonUserDoc.htm");

should work OK
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LVL 14

Expert Comment

by:Tommy Braas
ID: 10808767
=-)
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LVL 92

Expert Comment

by:objects
ID: 10809073
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