You may receive an error message pointing to the Java Authentication Filter Servlet. There are several ways to fix this problem, so we’ll look at them shortly.
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A Servlet Authentication Filter is a type of provider that performs pre and post processing for successful authentication, including identity verification. A Servlet Authentication Filter is a special type with a security provider that primarily acts as a “helper” for an authentication provider.
In Java web development, filters are used to implement and showing app authentication in addition to basic login and logout functions. A common scenario is when a user threatens to access a page that requires authentication and when they cannot log in, the application should display a login page. And after each user is professionally authenticated, they will be allowed access to any websites that require authentication. You can write standards in Java and JSP servlets to allow them to implement this type of authentication. Authentication code to create each page, which takes time, improves repetitive code and makes it difficult to maintain passwords.
is ideal as the main purpose of filters is to examine the whole request and transform the response. You need to write code that is only available for one filter class, so you don’t have to mess with JSP pages. Thus, this tutorial will help you understand and / or use filters to implement authentication in order to get the functionality for your website.
1. Filter A identifying The Code For The Administration Module
What is the Servlet authentication filter interface?
For example, forms certification is a two-requirement process, and the filter is called twice to develop authentication. The Servlet Authentication Filter UI allows the Authentication Provider to create zero or more Servlet Authentication Filter classes. Filters are named as follows:
As a rule, certification is required for all pages of the site administration module, except for the login page. Before configuring the filter for authentication, it is required that you perform the connect and disconnect functions with the following information:
– All admin pages may well be in the ContextPath / admin directory. Hence the URL of the admin home page is ContextPath / admin /
is the URL of the Java servlet that handles the connection request – ContextPath / admin / login
– Session Attribute Name – adminUser – This parameter is set immediately after the administrative user has successfully logged on to the system.
– If the user is not logged in alone, he will be redirected to all requests on the login page. This will prevent unauthorized administrator access to the page’s URL.
– When a user is submerged and a request is directed to login, they will be redirected to the admin home page. This prevents a particular user from logging in more than once unless they are logged out.em.
– If the customer is logged in and the request is only to not register, continue the watch chain – authorize the request to make sure you get there.
The following business plan describes the workflow that the certification filter processes for each individual request:
package net.codejava.admin;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.annotation.WebFilter;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;/ ** * This Java compression shows how you can intercept each of our requests. * and transform the response if you want to implement an authentication function. * for the back of this particular website. * * @ author of www.codejava.net * /@WebFilter ("/ admin / *")public class AdminAuthenticationFilter implements filterspublic void doFilter (ServletRequest, ServletResponse, FilterChain)throws IOException, ServletExceptionHttpServletRequest httpRequest (HttpServletRequest) matches the request;Session HttpSession = httpRequest.getSession (false);boolean isLoggedIn is (session! = null Session &&. getAttribute ("adminUser")! = null);String = loginURI httpRequest.getContextPath () + "/ admin / login";boolean = isLoginRequest httpRequest.getRequestURI () equals (loginURI);the boolean isLoginPage matches httpRequest.getRequestURI () .ndsWith ("login.jsp");if (isLoggedIn && (isLoginRequestpublic AdminLoginFilter ()avoid public destruction ()public void init (FilterConfig fConfig) throws ServletException
As you can see, the air filter is catching all requests with my URL pattern
/ Administrator / *doFilter ()
2. Authentication Code For The Front-end Pages Of The Site
Typically, websites in the front-end of a website have human access for all visitors, with the exception of some private pages that require authentication and logout functionality with the following details:
– All websites are located directly in the ContextPathdirectory. Hence the URL of the new website home page is just ContextPath /
is the URL of the Java servlet that handles the connection request – ContextPath / login
– Offer name in session – customerUser – this important attribute is set after one customer user has successfully logged into the systemhim.
– If the client is probably not logged in, and the attempt to open the page requires authentication, it will be redirected to login to the site. This unauthorized person prevents access to private market pages.
– If a customer gets wet and a connection request is made, they will be redirected to the site’s home page. This can prevent a client from logging in more than once if they are not logged out.
How to provide user authentication using filters in Java?
Hence, it provides user authentication through filters. As you know, we can create a filter class using the filter interface. With this filter class, we can assign multiple initialization parameters to one and compare its own values with the value entered by the user to authenticate the user.
– If a person is online and the policy does not provide for login, continue any filter chain – to allow the petition to achieve its goal.
The following process diagram describes the workflow that an authentication filter typically handles for virtual requests:
And below there should be a sample coffee filter code that implements the above workflow:
package net.codejava.frontend;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.annotation.WebFilter;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;/ ** 2. This Java filter shows how and how the request is intercepted. * and improve the answer to implement the authentication function (empty) for the front of the site. * 6. @ author of www.codejava.net * /@WebFilter ("/ *")Public class FrontEndAuthenticationFilter implements filtersprivate HTTP request;Fixed final line httpservletrequest private  loginRequiredURLs ="/ view_profile", "/ edit_profile", "/ update_profile";public void doFilter (ServletRequest, ServletResponse, FilterChain)throws IOException, ServletException isLoginPage))// User is already connected and will try again// connect and then redirect to someone's home pagehttpRequest.getRequestDispatcher ("/"). forward (request, response);otherwise, if (! isLoggedIn &&// isLoginRequired ()) the user is not logged in and needs the requested Facebook page// Authenticate, then on the membership pageLine loginPage = "/login.jsp";RequestDispatcher-Dispatcher means httpRequest.getRequestDispatcher (loginPage);Dispatcher.forward (request, response);different// for many other requested pages that do not require authentication// or the user is logged in permanently, further for most of the purposechain.doFilter (request, logicalNd answer);private isLoginRequired ()The requestURL line includes httpRequest.getRequestURL (). ToString ();for LoginRequiredURL (line: loginRequiredURLs)if (requestURL.contains (loginRequiredURL))returns true;false return;public CustomerLoginFilter ()destroy the public vacuum ()public void init (FilterConfig fConfig) throws ServletException
As you can imagine, this filter catches all requests that come to the site with a URL pattern
– This means that all category management requests (URL pattern
/ Administrator / *
) also look into this filter, so we have to exclude such requests with all of the following code at the beginning, including
string path = httpRequest.getRequestURI (). substring (httpRequest.getContextPath (). length ());if (path.startsWith ("/ admin /"))chain.doFilter (request, response);To return to;
Declare the urls of your pages requiring authentication in a nice table like:
private static final string  loginRequiredURLs ="/ view_profile", "/ edit_profile", "/ update_profile";
And all of the following methods check if a normal request requires authentication or not:
private boolean isLoginRequired ()The line requestURL = httpRequest.getRequestURL (). ToString ();for (loginRequiredURL string LoginRequiredURLs):if (requestURL.contains (loginRequiredURL))returns true;false return;
This is a sample code to help you understand how to enable filter authentication for a Java application in the online world. I also use swap separately in this tutorial
Java Servlet, JSP and Hibernate Courses
- How to create a Java Servlet Filter
- How to change the HTTP response using a Java filter
- How to write hit counter code for Java web applications
Other Java Servlet Guides:
- Java Servlet for Beginners (XML)
- Java servlet for less experienced people (note)
- Java Servlet and JSP Hello World Tutorial with Eclipse, Maven and Apache Tomcat
- How to use a session in an entire Java web application
- Example of loading a Java file with a servlet
- Sample Java File Upload Servlet
- Nam Ha Min
- Last updated June 30, 2019 & nbsp | & nbsp Print Email
About The Author In General:
Nam Ha Min
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