Spring with Thymeleaf Pagination for a List(Phân trang với spring và thymeleaf)

<dependency>
    <groupId>org.thymeleaf</groupId>
    <artifactId>thymeleaf-spring5</artifactId>
    <version>3.0.11.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-commons</artifactId>
    <version>2.3.2.RELEASE</version>
</dependency>

package com.example.templatecourseadmin.model;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import java.util.List;

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class Course {
    private int id;
    private String title;
    private String description;
    private String type;
    private String image;
    private List<String> topics;
    private int supporterId;
}

public Page<Course> findPaginated(Pageable pageable) {
        int pageSize = pageable.getPageSize();
        int currentPage = pageable.getPageNumber();
        int startItem = currentPage * pageSize;
        List<Course> list;

        if (FakeDB.courses.size() < startItem) {
            list = Collections.emptyList();
        } else {
            int toIndex = Math.min(startItem + pageSize, FakeDB.courses.size());
            list = FakeDB.courses.subList(startItem, toIndex);
        }

        Page<Course> coursePage
                = new PageImpl<Course>(list, PageRequest.of(currentPage, pageSize), FakeDB.courses.size());

@RequestMapping(value = "/", method = RequestMethod.GET)
    public String listBooks(
            Model model,
            @RequestParam("page") Optional<Integer> page,
            @RequestParam("size") Optional<Integer> size) {
        int currentPage = page.orElse(1);
        int pageSize = size.orElse(5);

        Page<Course> coursePage = courseService.findPaginated(PageRequest.of(currentPage - 1, pageSize));

        model.addAttribute("coursePage", coursePage);

        int totalPages = coursePage.getTotalPages();
        if (totalPages > 0) {
            List<Integer> pageNumbers = IntStream.rangeClosed(1, totalPages)
                    .boxed()
                    .collect(Collectors.toList());
            model.addAttribute("pageNumbers", pageNumbers);
        }

        return "course-list";
    }

<table>
   ...
<tbody>
                        <tr th:each="course,state:${coursePage.content}" >
                                <td th:text="${coursePage.size*(coursePage.number)+(state.index+1)}">1</td>
                            <td>
                                <a th:href="@{/edit/{id}(id=${course.id})}" th:text="${course.title}">SpringBoot - Web Back End</a>
                            </td>
                            <td th:text="${course.type}"
                                th:classappend="${course.type=='onlab'?'text-info':'text-warning'}">onlab</td>
                            <td th:text="${#strings.listJoin(course.topics, ', ')}"></td>
                        </tr>
                    </tbody>
                </table>

                <nav aria-label="Page navigation example">
                    <ul class="pagination justify-content-center pagination-sm">
                        <li  th:if="${coursePage.totalPages > 0}" class="page-link"
                              th:each="pageNumber : ${pageNumbers}">
                            <a th:href="@{/(size=${coursePage.size}, page=${pageNumber})}"
                               th:text=${pageNumber}
                               th:class="${pageNumber==coursePage.number + 1} ? active"
                               class="page-link"
                            ></a>
                        </li>
                    </ul>
                </nav>