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Protecting
your website with a login page
Some
sites require that all users log-in using a username and password,
before being able to visit any page.
This
can be done using JSP sessions or servlets, and in fact this was
a common technique for a while. But starting with a new release
of Servlets specifications (2.2) from Sun, this feature is now very
simple to implement.
It
is no longer necessary to use JSP techniques to provide login/password
protection, but it is still a very common requirement of web-sites,
therefore a brief overview is provided here.
To
password-protect your site, you just need to design a login page.
This page can be as simple or complicated as you need it to be.
It must contain a <FORM> tag, with the METHOD set to POST
and the ACTION set to "j_security_check".
<FORM
METHOD=POST ACTION=j_security_check>
The
target j_security_check is provided by the application server, and
does not need to be coded.
The
form must contain two <INPUT> fields, named j_username and
j_password respectively for the username and password. Typically,
the username field will be a TEXT input field, and the password
field will be a PASSWORD input field.
After
this, you must tell your application server to password protect
your pages using the login page you have provided. The details will
vary from server to server, but a good implementation will provide
you hooks that you can use, for example, to match usernames and
passwords against a database. (E.g., in Blazix you can supply an
implementation of the interface desisoft.deploy.AuthCheck to check
usernames and passwords against a database or other sources.)
Exercise:
Read your application server's documentation and add login/password
protection to some of your JSPs.
Next
Tutorial: Using SQL in JSP pages
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