You can create a form login page and an error page to authenticate a user.
The Hypertext Transfer Protocol (HTTP) basic authentication transmits a user password from the web client to the web server in simple base64 encoding. Form-based authentication transmits a user password from the browser to the web server in plain text. Therefore, both HTTP basic authentication and form-based authentication are not very secure unless the HTTPS protocol is used.
The web application deployment descriptor contains information about which authentication mechanism to use. When form-based authentication is used, the deployment descriptor also contains entries for login and error pages. A login page can be either an HTML page or a JavaServer Pages (JSP) file. This login page is displayed on the web client side when a secured resource (servlet, JSP file, HTML page) is accessed from the application. On authentication failure, an error page is displayed. You can write login and error pages to suit the application needs and control the look and feel of these pages. During assembly of the application, an assembler can set the authentication mechanism for the application and set the login and error pages in the deployment descriptor.
<form method="POST" action="j_security_check">
<input type="text" name="j_username">
<input type="text" name="j_password">
<\form>
Use the j_username input field to get the user name, and use the j_password input field to get the user password.
On receiving a request from a web client, the web server sends the configured form page to the client and preserves the original request. When the web server receives the completed form page from the web client, the server extracts the user name and password from the form and authenticates the user. On successful authentication, the web server redirects the call to the original request. If authentication fails, the web server redirects the call to the configured error page.
<!DOCTYPE HTML PUBLIC "-//W3C/DTD HTML 4.0 Transitional//EN">
<html>
<META HTTP-EQUIV = "Pragma" CONTENT="no-cache">
<title> Security FVT Login Page </title>
<body>
<h2>Form Login</h2>
<FORM METHOD=POST ACTION="j_security_check">
<p>
<font size="2"> <strong> Enter user ID and password: </strong></font>
<BR>
<strong> User ID</strong> <input type="text" size="20" name="j_username">
<strong> Password </strong> <input type="password" size="20" name="j_password">
<BR>
<BR>
<font size="2"> <strong> And then click this button: </strong></font>
<input type="submit" name="login" value="Login">
</p>
</form>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C/DTD HTML 4.0 Transitional//EN">
<html>
<head><title>A Form login authentication failure occurred</head></title>
<body>
<H1><B>A Form login authentication failure occurred</H1></B>
<P>Authentication may fail for one of many reasons. Some possibilities include:
<OL>
<LI>The user-id or password may be entered incorrectly; either misspelled or the
wrong case was used.
<LI>The user-id or password does not exist, has expired, or has been disabled.
</OL>
</P>
</body>
</html>
<login-config id="LoginConfig_1">
<auth-method>FORM<auth-method>
<realm-name>Example Form-Based Authentication Area</realm-name>
<form-login-config id="FormLoginConfig_1">
<form-login-page>/login.html</form-login-page>
<form-error-page>/error.jsp</form-error-page>
</form-login-config>
</login-config>
META-INF
META-INF/MANIFEST.MF
login.html
error.jsp
WEB-INF/
WEB-INF/classes/
WEB-INF/classes/aServlet.class
Form logout is a mechanism to log out without having to close all Web-browser sessions. After logging out of the form logout mechanism, access to a protected web resource requires re-authentication. This feature is not required by J2EE specifications, but it is provided as an additional feature in WebSphere Application Server security.
Form logout does not require any attributes in a deployment descriptor. The form-logout page is an HTML or a JavaServer Pages (JSP) file that is included with the web application. The form-logout page is like most HTML forms except that like the form-login page, the form-logout page has a special post action. This post action is recognized by the web container, which dispatches the post action to a special internal form-logout servlet. The post action in the form-logout page must be ibm_security_logout.
You can specify a logout-exit page in the logout form and the exit page can represent an HTML or a JSP file within the same web application to which the user is redirected after logging out. Additionally, the logout-exit page permits a fully qualified URL in the form of http://hostname:port/URL. The logout-exit page is specified as a parameter in the form-logout page. If no logout-exit page is specified, a default logout HTML message is returned to the user.
<!DOCTYPE HTML PUBliC "-//W3C/DTD HTML 4.0 Transitional//EN">
<html>
<META HTTP-EQUIV = "Pragma" CONTENT="no-cache">
<title>Logout Page </title>
<body>
<h2>Sample Form Logout</h2>
<FORM METHOD=POST ACTION="ibm_security_logout" NAME="logout">
<p>
<BR>
<BR>
<font size="2"><strong> Click this button to log out: </strong></font>
<input type="submit" name="logout" value="Logout">
<INPUT TYPE="HIDDEN" name="logoutExitPage" VALUE="/login.html">
</p>
</form>
</body>
</html>