1. Overview
1.概述
In this quick tutorial, we’ll build a simple application to display a list of items with pagination using Spring and Thymeleaf.
在这个快速教程中，我们将构建一个简单的应用程序，使用Spring和Thymeleaf显示一个带分页的项目列表。
For an introduction on how to integrate Thymeleaf with Spring, please take a look at our article here.
关于如何将Thymeleaf与Spring集成的介绍，请看我们的文章这里。
2. Maven Dependencies
2.Maven的依赖性
Besides the usual Spring dependencies, we’ll add the dependencies for Thymeleaf and Spring Data Commons:
除了常见的Spring依赖关系，我们将添加Thymeleaf和Spring Data Commons的依赖关系。
<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>We can find the latest thymeleaf-spring5 and spring-data-commons dependencies in the Maven Central repository.
我们可以在Maven Central仓库中找到最新的thymeleaf-spring5和spring-data-commons依赖项。
3. Models
3.模型
Our sample application will demonstrate pagination for a list of books.
我们的示例应用程序将展示一个图书列表的分页。
First, let’s define a Book class with two fields and an all-arguments constructor:
首先，让我们定义一个有两个字段和一个全参数构造函数的Book类。
public class Book {
private int id;
private String name;
// standard constructor, setters and getters
}4. Service
4.服务
Then we’ll create a service to generate the paginated book list for the requested page using the Spring Data Commons library:
然后我们将创建一个服务，使用Spring Data Commons库为请求的页面生成分页的图书列表。
@Service
public class BookService {
final private List<Book> books = BookUtils.buildBooks();
public Page<Book> findPaginated(Pageable pageable) {
int pageSize = pageable.getPageSize();
int currentPage = pageable.getPageNumber();
int startItem = currentPage * pageSize;
List<Book> list;
if (books.size() < startItem) {
list = Collections.emptyList();
} else {
int toIndex = Math.min(startItem + pageSize, books.size());
list = books.subList(startItem, toIndex);
}
Page<Book> bookPage
= new PageImpl<Book>(list, PageRequest.of(currentPage, pageSize), books.size());
return bookPage;
}
}In the above service, we created a method to return the selected Page based on requested page, which is represented by the Pageable interface. The PageImpl class helps to filter out the paginated list of books.
在上述服务中，我们创建了一个方法来返回基于请求的页面所选择的Page，它由Pageable接口表示。PageImpl类有助于过滤出分页的书籍列表。
5. Spring Controller
5.Spring控制器
We’ll need a Spring controller to retrieve the book list of a selected page when given the page size and current page number.
我们需要一个Spring控制器来当给定页面大小和当前页码时，检索所选页面的图书列表。
To use the default values for selected page and page size, we can simply access the resource at /listBooks, without any parameters.
要使用选定页面和页面大小的默认值，我们可以简单地访问/listBooks的资源，而不需要任何参数。
If any page size or specific page is required, we can add parameters page and size.
如果需要任何页面大小或特定页面，我们可以添加参数page和size。
For example, /listBooks?page=2&size=6 will retrieve page two with six items per page:
例如，/listBooks?page=2&size=6将检索到第二页，每页有六个项目。
@Controller
public class BookController {
@Autowired
private BookService bookService;
@RequestMapping(value = "/listBooks", 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<Book> bookPage = bookService.findPaginated(PageRequest.of(currentPage - 1, pageSize));
model.addAttribute("bookPage", bookPage);
int totalPages = bookPage.getTotalPages();
if (totalPages > 0) {
List<Integer> pageNumbers = IntStream.rangeClosed(1, totalPages)
.boxed()
.collect(Collectors.toList());
model.addAttribute("pageNumbers", pageNumbers);
}
return "listBooks.html";
}
}To prepare our pagination for the view, we’ve added model attributes in the Spring controller, including the selected Page and a list of page numbers.
为了给视图准备分页，我们在Spring控制器中添加了模型属性，包括选定的Page和一个页码列表。
6. Thymeleaf Template
6.百里香树叶模板
Now it’s time to create a Thymeleaf template “listBooks.html”, which displays the list of books with pagination based on model attributes from our Spring controller.
现在是时候创建一个Thymeleaf模板“listBooks.html”，该模板根据Spring控制器的模型属性分页显示书籍列表。
First, we iterate the list of books and display them in a table. Then we show the pagination when the total number of pages is greater than zero.
首先，我们迭代图书列表，并将其显示在一个表中。然后，我们在总页数大于0时显示分页。
Every time we click and select a page, the corresponding list of books will be displayed with the current page link highlighted:
每当我们点击并选择一个页面时，相应的书籍列表就会显示出来，并突出显示当前页面的链接。
<table border="1">
<thead>
<tr>
<th th:text="#{msg.id}" />
<th th:text="#{msg.name}" />
</tr>
</thead>
<tbody>
<tr th:each="book, iStat : ${bookPage.content}"
th:style="${iStat.odd}? 'font-weight: bold;'"
th:alt-title="${iStat.even}? 'even' : 'odd'">
<td th:text="${book.id}" />
<td th:text="${book.name}" />
</tr>
</tbody>
</table>
<div th:if="${bookPage.totalPages > 0}" class="pagination"
th:each="pageNumber : ${pageNumbers}">
<a th:href="@{/listBooks(size=${bookPage.size}, page=${pageNumber})}"
th:text=${pageNumber}
th:class="${pageNumber==bookPage.number + 1} ? active"></a>
</div>7. Conclusion
7.结语
In this article, we demonstrated how we can paginate a list using Thymeleaf with the Spring framework.
在这篇文章中，我们演示了如何使用Thymeleaf和Spring框架对一个列表进行分页。
As usual, all the code samples used in the article are available over on GitHub.
像往常一样，文章中使用的所有代码样本都可以在GitHub上找到。