Spring Security Tag Library

The Spring Security features into your web pages, you often use JSP (JavaServer Pages), Thymeleaf, or other templating engines. Here’s how you can incorporate Spring Security-related functionality:

1. JSP (JavaServer Pages):
JSP is a standard view technology that can be used to render HTML. To use Spring Security features in JSP, you can utilize the JSTL (JavaServer Pages Standard Tag Library) and access Spring Security attributes via EL (Expression Language).

Example JSP code:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<c:if test="${not empty #request.userPrincipal}">
    Welcome, ${#request.userPrincipal.name}!
    <c:if test="${request.isUserInRole('ROLE_ADMIN')}">
        You have admin privileges.
    </c:if>
</c:if>

2. Thymeleaf:
Thymeleaf is a modern server-side Java template engine. To utilize Spring Security with Thymeleaf, you typically use Thymeleaf’s attributes, such as th:if and th:unless, along with Spring Security expressions.

Example Thymeleaf code:

<div th:if="${#authentication.principal != null}">
    Welcome, <span th:text="${#authentication.principal.name}"></span>!
    <div th:if="${#authorization.expression('hasRole(''ROLE_ADMIN'')')}">
        You have admin privileges.
    </div>
</div>

Remember to configure your Spring Security properly so that authentication and authorization information is available in your templates. Also, note that these examples are simple and may need adjustments based on your application’s exact configuration.

Please check the official Spring Security documentation and the documentation for your chosen templating engine for the latest information and best practices, as there might have been developments since my last update.