Uploading Multiple Files from web client to web server

Question

Am using a Digitally signed applet to pickup files from a specific directory and only to pickup those of a specific type. Applet is called by a HTML converted page and uses the JAVA 1.3.1 plug-in. Client side is ok, but the server side does not work - cannot see how to drop the files down onto the web server.
code
URL url = null ;
FileInputStream filReader = null ;
DataOutputStream dosOutfile = null ;
HttpURLConnection httpUrlConn = null ;
int bytes = 0 ;
//read local file on client's hd with signed applet
try
filReader = new FileInputStream( new File( fromFile ) );
catch ( java.io.FileNotFoundException eNotFound )
DisplayStatus ( fromFile + " Not found");
eNotFound.printStackTrace();
// start setup to server-side copy of in file
try
url = new URL ( toFile ) ;
catch ( java.net.MalformedURLException eMalFormedUrl )
DisplayStatus ( url + " url mal formed");
eMalFormedUrl.printStackTrace();
// create a HttpUrl connection for POSTING
try
httpUrlConn = (HttpURLConnection) url.openConnection(); // do not remove this casting, as needed
catch ( java.io.IOException eIoException )
DisplayStatus ( url + " IO not possible");
eIoException.printStackTrace();
// set preferences
httpUrlConn.setDoInput(true); // default value, but best make sure
httpUrlConn.setDoOutput(true); // default value, but best make sure
httpUrlConn.setUseCaches(false); // enable write straight through
try
httpUrlConn.setRequestMethod("POST") ;
// httpUrlConn.setRequestMethod("PUT") ;
} catch ( java.net.ProtocolException eProtEx )
DisplayStatus ( "Protocol Exception on setting up POST") ;
eProtEx.printStackTrace();
httpUrlConn.setRequestProperty("Content-Type", "multipart/form-data");
// permissions?
try
java.security.Permission permission = httpUrlConn.getPermission() ;
if ( iDebug == true )
DisplayStatus ("Permission = " + permission.toString() ) ;
DisplayStatus ( "Actions = " + permission.getActions() ) ;
DisplayStatus ( "Name = " + permission.getName() ) ;
catch ( java.io.IOException eUrlIOConnException )
DisplayStatus ( "httpUrl " + httpUrlConn + " IO not possible");
DisplayStatus ( eUrlIOConnException.toString() ) ;
eUrlIOConnException.printStackTrace();
// connect
try
this.VerifyHttpResponseCode ( httpUrlConn.getResponseCode() ) ;
DisplayStatus ("About to connect") ;
httpUrlConn.connect() ;
DisplayStatus ("Connected") ;
if ( iDebug == true )
DisplayStatus ("Connected Content Encoding = " + httpUrlConn.getContentEncoding() ) ;
DisplayStatus ("Connected Content Length = " + httpUrlConn.getContentLength() ) ;
DisplayStatus ("Connected Content Type = " + httpUrlConn.getContentType() ) ;
DisplayStatus ("Connected default allow user interaction = " + httpUrlConn.getDefaultAllowUserInteraction() ) ;
DisplayStatus ("Connected File Map = " + httpUrlConn.getFileNameMap() ) ;
DisplayStatus ("Connected request method = " + httpUrlConn.getRequestMethod() ) ;
DisplayStatus ("Connected response code = " + httpUrlConn.getResponseCode() ) ;
DisplayStatus ("Connected response message = " + httpUrlConn.getResponseMessage() ) ;
DisplayStatus ("Connected = " + httpUrlConn.getURL() ) ;
} // end of debug print out status
catch ( java.net.ConnectException eConnEx )
this.DisplayStatus ( "Connection error - no server listening or incorrect port " ) ;
this.DisplayStatus ( "Connection error - http = " + httpUrlConn) ;
eConnEx.printStackTrace();
catch ( java.io.IOException eUrlConnException )
DisplayStatus ( "url " + url + " connection not possible");
DisplayStatus ( eUrlConnException.toString() ) ;
eUrlConnException.printStackTrace();
// create file on server
try
dosOutfile = new DataOutputStream ( new BufferedOutputStream( httpUrlConn.getOutputStream () ) ) ;
catch ( java.io.IOException eNewFileIO )
DisplayStatus ("Unable to create file on server / buffer output stream " + toFile ) ;
// copy files char by char for the moment, till testing complete
try
bytes = filReader.read();
while(bytes != -1)
dosOutfile.writeByte(bytes);
bytes = filReader.read();
// close both files
dosOutfile.flush ();
dosOutfile.close ();
filReader.close();
catch (java.io.IOException eCpyIo )
DisplayStatus ("Error copying files") ;
connection of the HttpURLConnection
gives 'Fobbiden' response for 'PUT'
and
'method not allowed' for 'POST'
trying to create the file on the server than causes IOException at the create DataStream line
What am I doing wrong?
Is this philosphy correct?
Should the HttpURLConnection be to the target folder
and then create the file in it?

Answer 1

hello,
first here is my interpretation of your prob.
You have a client.From this client you are trying to upload files onto a server.
Finding the files and reading them on the client side is not a prob. The prob is storing them on the server side.
right?
If the above stated prob is right, here is a solution.
1. You have to first inform the server that you are sending the file. Unless you do so the server will not understand when you have started sending the file.
So, initially, the applet which you have written need to communicate with a servlet on the server side.
This can be done using reqs.. .get or post.In the req itself you can even send the name of the folder wherein you want to store the file you are going to transfer later on.
Next, after receiving the folder name, the servlet can now understand that next file data is going to be received.
The applet now sends the file which is received by the servlet and stored appropriately.
You need to explicitly write a servlet to receive a data into the file and then store the file into appropriate folder.
for any further probs email me at [email protected]