1. Spring Boot Thymeleaf Error Page
2. Spring Thymeleaf Example

Thymeleaf is a server-side Java templating engine commonly used in web applications that utilize the Spring framework. In this article, we'll cover how to detect if a user is logged in. This is particularly useful for displaying different content on unsecured pages based on authenticated status. This tutorial demonstrates how to configure spring-boot, spring-security and thymeleaf with form-login.We secure our web application using spring security form-login. We create a reusable Thymeleaf layout which we can use to create our secured and unsecured pages.

We will develop a simple User Registration Module using Spring Boot 2, Spring MVC, Spring Security, Hibernate 5, Thymeleaf and MySQL. We validate the user registration fields with hibernate validator annotations and a custom field matching validator to validate if the email and/or password fields match. We will create Role-based Spring security with a MySQL database.We will develop two main functionalities:1. Register user (stored data into MySQL database).2. Login Authentication - validate user login credentials with database email and password. We configure Hibernate using the application.properties file located in the src/main/resources/ folder.

Spring Boot Thymeleaf Error Page

Note that we also configure thymeleaf view resolver. This controller is mapped to “/registration” URI. We use the UserRegistrationDto to process and validate the user registration form and inject it using the @ModelAttribute('user') annotation. When the form is submitted it’s automatically validated and errors are available in the BindingResult. Next, we check if a user doesn’t already exist with the submitted email. If the form has any errors, we return to the registration page.

Otherwise, we redirect and inform the user the registration procedure is complete.

Springorg.springframework.web.servlet.DispatcherServlet1spring/org.springframework.web.context.ContextLoaderListenercontextConfigLocation/WEB-INF/spring-security.xmlspringSecurityFilterChainorg.springframework.web.filter.DelegatingFilterProxyspringSecurityFilterChain/.Step 4: Add security specific configuration in spring-security.xmlLet's create spring-security.xml under WEB-INF folder to add spring security configuration.spring-security.xml. In the above security configuration xml file we have used element.

Spring Thymeleaf Example

/WEB-INF/views/.jspStep 6: Creating Spring MVC ControllerCreate the LoginController class to map the requests.