Database connectivity from Applets

hi
as far as the applet goes it can only connecdt to the server from which it is downloaded
o if u want to connect to some other server then u have to sign the applet
applet signing pls refer following
http://www.ryerson.ca/~dgrimsha/courses/cps530/SigningScript.html

http://www.object-arts.com/Lib/EducationCentre4/htm/appletcodesigning.htm

As rjackman states, applets are restricted by the browswers security sandbox to only allow HTTP access from the server they were downloaded. The port JDBC uses is also blocked.

This leaves you with a few alternatives:

1.- Create a signed applet, again as rjackman suggests, and request the user for authorization to access th DB.

2.- Encapsulate your JDBC calls inside an HTTP packet (HTTP Tunneling).

3.- Use RMI (which is not blocked by the browser) to write a wrapper over JDBC that will allow you to make calls to a remote RMI server. This server will then act as a Proxy between the applet and the DB.


Option 1 is perhaps the simplest, but you are forced to create two versions: one for Netscape and one for IE. Additionaly, you will have to purchase Level 2 digital signatures.

Option 2 is the most complex option, it implies writting proxies on both the client and server ends. On the plus side, its the most flexible option.

Option 3 is perhaps your best bet. Its quite simple to define and implement an interface that forwards your client side JDBC calls to an RMI server. RMI even has support for HTTP tunneling in case you have to go through firewalls.

If you don't mind using ODBC, you can download a free JDBC-ODBC driver that runs over RMI called RMI-JDBC from:

http://www.objectweb.org/RmiJdbc/

hope this helps.

Here'a PAQ discussing JDBC communication from an applet that you may find helpful:

https://www.experts-exchange.com/jsp/qManageQuestion.jsp?ta=java&qid=20134997

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