步骤1：创建分页工具类（PageVo）
分页工具类是实现分页功能的核心，用于封装分页相关的属性和逻辑。
创建文件：src/cn/wolfcode/PageVo.java
package cn.wolfcode;import lombok.Data;
import java.util.ArrayList;
import java.util.List;@Data
public class PageVo<E> {private int curPage = 1; // 当前页码，默认值为1private int pageSize = 5; // 每页显示的记录数，默认值为5private int totalRows; // 总记录数private int totalPage; // 总页数private List<E> data; // 存储分页数据的集合// 设置数据并触发分页逻辑public void setData(List<E> data) {this.totalRows = data.size(); // 计算总记录数this.totalPage = (totalRows + pageSize - 1) / pageSize; // 计算总页数// 确保当前页码在有效范围内if (curPage < 1) {curPage = 1;}if (curPage > totalPage) {curPage = totalPage;}// 截取当前页的数据List<E> smallList = new ArrayList<>();for (int i = (curPage - 1) * pageSize; i < curPage * pageSize && i < totalRows; i++) {smallList.add(data.get(i));}this.data = smallList;}
}
步骤2：服务层封装分页数据
服务层负责调用数据访问层获取数据，并封装到分页对象中。
创建/修改文件：src/cn/wolfcode/service/impl/BookServiceImpl.java
@Override
public PageVo<Book> selectAllBypage(int curPage) {// 1. 查询所有图书数据List<Book> bookList = bookMapper.selectAll();// 2. 封装到PageVo对象PageVo<Book> bookPageVo = new PageVo<>();bookPageVo.setCurPage(curPage); // 设置当前页码bookPageVo.setData(bookList); // 触发分页逻辑return bookPageVo; // 返回分页对象
}
步骤3：控制器层处理分页请求
控制器层接收用户请求中的分页参数，调用服务层获取分页数据，并转发到视图。
创建/修改文件：src/cn/wolfcode/servlet/BookServlet.java
@Override
public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {// 转换为HttpServletRequest和HttpServletResponseHttpServletRequest request = (HttpServletRequest) req;HttpServletResponse response = (HttpServletResponse) res;// 设置字符编码request.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");// 1. 获取当前页码参数String curPageStr = request.getParameter("curPage");int curPage = 1; // 默认值为1if (curPageStr != null && !"".equals(curPageStr.trim())) {curPage = Integer.valueOf(curPageStr);}// 2. 调用服务层方法获取分页数据PageVo<Book> books = bookService.selectAllBypage(curPage);// 3. 将分页数据设置到请求属性中request.setAttribute("books", books);// 4. 转发到JSP视图request.getRequestDispatcher("/WEB-INF/jsp/book/bookList.jsp").forward(request, response);
}
步骤4：创建/修改JSP视图
JSP视图负责展示分页数据和分页导航链接。
创建/修改文件：web/WEB-INF/jsp/book/bookList.jsp
<%@ page import="java.util.List" %>
<%@ page import="cn.wolfcode.domain.Book" %>
<%@ page import="cn.wolfcode.PageVo" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>图书列表</title><script type="text/javascript">// 首页function first() {document.getElementById("curPage").value = 1;document.getElementById("f1").submit();}// 上一页function pre() {var curPage = parseInt(document.getElementById("curPage").value);if (curPage > 1) {document.getElementById("curPage").value = curPage - 1;document.getElementById("f1").submit();}}// 下一页function next() {var curPage = parseInt(document.getElementById("curPage").value);var totalPage = parseInt(document.getElementById("totalPage").value);if (curPage < totalPage) {document.getElementById("curPage").value = curPage + 1;document.getElementById("f1").submit();}}// 尾页function last() {var totalPage = parseInt(document.getElementById("totalPage").value);document.getElementById("curPage").value = totalPage;document.getElementById("f1").submit();}</script>
</head>
<body>
<form action="/books" method="post" id="f1"><table align="center" width="80%"><tr align="center"><th>编号</th><th>书名</th><th>作者</th><th>售价</th><th>进价</th><th>分类</th></tr><%-- 显示图书列表 --%><% PageVo<Book> books = (PageVo<Book>) request.getAttribute("books");for (Book book : books.getData()) {%><tr align="center"><td><%= book.getId() %></td><td><%= book.getBname() %></td><td><%= book.getAuthor() %></td><td><%= book.getSalePrice() %></td><td><%= book.getCostPrice() %></td><td><%= book.getClassify() == 1 ? "国外文学" : "国内文学" %></td></tr><% }%><%-- 分页导航 --%><tr align="center"><td colspan="6"><a href="#" onclick="first()">首页</a> | <a href="#" onclick="pre()">上一页</a> | <a href="#" onclick="next()">下一页</a> | <a href="#" onclick="last()">尾页</a><span>第<%= books.getCurPage() %>页，共<%= books.getTotalPage() %>页</span></td></tr><%-- 隐藏字段 --%><input type="hidden" name="curPage" id="curPage" value="<%= books.getCurPage() %>"><input type="hidden" name="totalPage" id="totalPage" value="<%= books.getTotalPage() %>"></table>
</form>
</body>
</html>