Thymleaf TemplateProcessingException Could not parse as expression:

TemplateProcessingException: Could not parse as expression:

타임리프는 표현식으로 " " 를 사용한다. 문자열로 switch case 문 작성시 'A'일때 조건식을 th:case="A" 또는 th:case = 'A'를 하면 위의 오류가 발생한다.
따라서 아래와 같이 문자열을 작은 따옴표로 감싸줘야합니다. "A" -> "'A'".....

Code

                <span th:switch="${grade}">
                    <h2 class="font-bold text-6xl mb-4" th:case="'A+'">Excellent! This web page achieves a carbon rating of A+, setting a great example for eco-friendly web design. </h2>
                    <h2 class="font-bold text-6xl mb-4" th:case="'A'">Great job! This web page has a carbon rating of A, demonstrating a strong commitment to reducing its environmental impact. </h2>
                    <h2 class="font-bold text-6xl mb-4" th:case="'B'">Well done! Your web page has earned a carbon rating of B, showing good eco-friendly practices. </h2>
                    <h2 class="font-bold text-6xl mb-4" th:case="'C'">Good effort! This web page has a carbon rating of C. There's room for improvement, but you're on the right track. </h2>
                    <h2 class="font-bold text-6xl mb-4" th:case="'D'">A decent start! This web page has a carbon rating of D. Consider optimizing further to reduce your carbon footprint. </h2>
                    <h2 class="font-bold text-6xl mb-4" th:case="'E'">Needs improvement. This web page has a carbon rating of E. Look into more eco-friendly options to enhance your rating. </h2>
                    <h2 class="font-bold text-6xl mb-4" th:case="'F'">Oh no! This web page achieves a carbon rating of F. It's time to rethink and implement greener web solutions. </h2>
                </span>