javabean servlet jsp实现分页功能代码解析

摘要：前端实现用ligerUI实现分页，感觉用框架确实简单，闲着无聊，模拟着liger的分页界面实现了一遍（只要是功能，样式什么无视）这里用基础的...

前端实现用ligerUI实现分页，感觉用框架确实简单，闲着无聊，模拟着liger的分页界面实现了一遍（只要是功能，样式什么无视）

这里用基础的三层架构+servlet+jsp实现，思路很简单，把所有分页相关信息写入到一个pagebean类里面，service返回这个bean类，每次分页查询时都从该bean里查找信息。只是其中的细节问题比较繁琐，如边界处理（前端和后台边界都要处理），下拉框跳转后要显示当前页等等

这是ligerUI实现的分页样式（实现过程我的上一篇博客有写：http://www.jb51.net/article/92850.htm）

javabean servlet jsp实现分页功能代码解析1

模拟实现过程：

目录结构

javabean servlet jsp实现分页功能代码解析2

数据库（mysql）

javabean servlet jsp实现分页功能代码解析3

model层,一个数据库对应的model（Blog），还有一个pageBean(BlogPage)

import java.sql.Date; public class Blog { private int id; private int category_id; private String title; private String content; private Date created_time; //getter和setter方法 @Override public String toString() { return "Blog [id=" + id + ", category_id=" + category_id + ", title=" + title + ", content=" + content + ", created_time=" + created_time + "]"; } }

public class BlogPage { private List<Blog> pagerecord;//每页记录 private int pageno;//当前页 private int pagenostart;//每页开始索引 private int pagesize=5;//每页多少数据 private int totalrecord;//总记录数 private int totalpage;//总页数 public BlogPage(int pageno,int totalrecord){ //pageno totalrecord都可以当做已有信息 this.totalrecord=totalrecord; //计算总页数 totalpage=(totalrecord%pagesize==0)?totalrecord/pagesize:totalrecord/pagesize+1; //pageno的边界处理 if(pageno<=1) this.pageno=1; else if(pageno>=totalpage) this.pageno=totalpage; else this.pageno=pageno; //计算每页开始索引，即每页第一个数据的索引，用于分页查询 pagenostart=(this.pageno-1)*pagesize; } public int getPagenostart() { return pagenostart; } public void setPagenostart(int pagenostart) { this.pagenostart = pagenostart; } public List<Blog> getPagerecord() { return pagerecord; } public void setPagerecord(List<Blog> pagerecord) { this.pagerecord = pagerecord; } public int getPageno() { return pageno; } public void setPageno(int pageno) { this.pageno = pageno; } public int getPagesize() { return pagesize; } public void setPagesize(int pagesize) { this.pagesize = pagesize; } public int getTotalrecord() { return totalrecord; } public void setTotalrecord(int totalrecord) { this.totalrecord = totalrecord; } public int getTotalpage() { return totalpage; } public void setTotalpage(int totalpage) { this.totalpage = totalpage; } }

dao层

JDBCUtil封装了jdbc的连接和释放操作

public class JDBCUtil { private static String url = "jdbc:mysql://localhost:3306/blogs_stu"; private static String username = "root"; private static String password = ""; static { try { Class.forName("com.mysql.jdbc.Driver"); } catch (Exception e) { e.printStackTrace(); } } public static Connection getConnection(){ Connection conn; try { conn= DriverManager.getConnection(url, username, password); return conn; } catch (SQLException e) { e.printStackTrace(); } return null; } public static void release(ResultSet rs,PreparedStatement ps,Connection conn){ if(rs!=null){ try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } if(ps!=null){ try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } } if(conn!=null){ try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } }

public class BlogDao { //每页的记录，传入每页开始索引和每页大小用于分页，即limit的两个参数（mysql分页用limit） public List<Blog> getPageRecord(int pagenostart, int pagesize) { Connection conn = JDBCUtil.getConnection(); PreparedStatement ps = null; ResultSet rs = null; String sql = "select * from blog limit "; List<Blog> list = new ArrayList<Blog>(); try { ps = conn.prepareStatement(sql); ps.setInt(1, pagenostart); ps.setInt(2, pagesize); rs = ps.executeQuery(); while (rs.next()) { Blog blog = new Blog(); blog.setId(rs.getInt("id")); blog.setCategory_id(rs.getInt("category_id")); blog.setTitle(rs.getString("title")); blog.setContent(rs.getString("content")); blog.setCreated_time(rs.getDate("created_time")); list.add(blog); } return list; } catch (SQLException e) { e.printStackTrace(); } finally { JDBCUtil.release(rs, ps, conn); } return null; } //总记录数 public int getTotal() { Connection conn = JDBCUtil.getConnection(); PreparedStatement ps = null; ResultSet rs = null; try { ps = conn.prepareStatement("select count(*) from blog"); rs = ps.executeQuery(); if (rs.next()) { return rs.getInt(1); } } catch (SQLException e) { e.printStackTrace(); } finally { JDBCUtil.release(rs, ps, conn); } return 0; } }

service层

public class BlogService { BlogDao blogDao = new BlogDao(); //返回pagebean,所有分页需要的信息都去pagebean里查找 public BlogPage findPageRecord(int pageno) { int totalrecord = blogDao.getTotal(); BlogPage blogpage = new BlogPage(pageno, totalrecord); List<Blog> list = blogDao.getPageRecord(blogpage.getPagenostart(),blogpage.getPagesize()); blogpage.setPagerecord(list); return blogpage; } }

servlet类

@WebServlet("/BlogSplitServlet") public class BlogSplitServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); response.setContentType("text/html; charset=utf-8"); String pagenostr=request.getParameter("pageno"); //首次访问servletpagenostr为null，给一个初始值，即默认访问第一页 int pageno=1; if(pagenostr!=null) pageno=Integer.parseInt(pagenostr); BlogService service=new BlogService(); BlogPage blogPage=service.findPageRecord(pageno); request.setAttribute("blogPage", blogPage); request.getRequestDispatcher("/blogPage.jsp").forward(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }

这样所有的分页信息就封装到pagebean里了

jsp实现只需要将pagebean里的信息取出来就行了

下面给出我的jsp实现（模拟ligerUI）

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <%@page import="java.util.*,model.Blog,model.BlogPage"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Insert title here</title> <script type="text/javascript"> window.onload = function() { //保证select的option与当前页显示一致 select = document.getElementById("select"); pageno = '${blogPage.pageno}'; select.options[pageno - 1].selected = 'selected'; } //select下拉列表跳转 function selectjump() { var pageno = select.selectedIndex + 1; window.location.href = "http://localhost/jspPageSplit/BlogSplitServlet" + pageno; } //text跳转，onblur事件，输入框失去焦点是发生 function textjump() { var pageno = document.getElementById("text").value; window.location.href = "http://localhost/jspPageSplit/BlogSplitServlet" + pageno; } </script> </head> <body> <% BlogPage blogPage = (BlogPage) request.getAttribute("blogPage"); List<Blog> list = blogPage.getPagerecord(); // 尾页填充空白行，若不填充，尾页表格tr行数与前面不一致很难看 if (list.size() < blogPage.getPagesize()) { for (int i = list.size(); i < blogPage.getPagesize(); i++) list.add(null); } %> <div> <table border="1" cellspacing="0" width="100%" bgcolor="#CEF0C5"> <tr height="40px"> <td>id</td><td>标题</td><td>内容</td><td>创建时间</td> </tr> <% for (Blog blog : list) { if (blog != null) { %> <tr height="50px"> <td width="10%"><%=blog.getId()%></td> <td width="20%"><%=blog.getTitle()%></td> <td width="40%"><%=blog.getContent()%></td> <td width="30%"><%=blog.getCreated_time()%></td> </tr> <> <%} else {%> <tr height="50px"> <td width="10%"></td> <td width="20%"></td> <td width="40%"></td> <td width="30%"></td> </tr> <%}}%> </table> <div> <> <select id="select"> <%for (int i = 1; i <= blogPage.getTotalpage(); i++) {%> <option><%=i%></option> <%}%> </select> <a href="${pageContext.request.contextPath}/BlogSplitServlet">首页</a> <a href="${pageContext.request.contextPath}/BlogSplitServlet?pageno=<%=blogPage.getPageno()-1<1?blogPage.getPageno():blogPage.getPageno()-1%>">上一页</a> <input type="text" id="text" size="1px" value="${blogPage.pageno}" onblur="textjump()">/${blogPage.totalpage} <a href="${pageContext.request.contextPath}/BlogSplitServlet?pageno=<%=blogPage.getPageno()+1>blogPage.getTotalpage()?blogPage.getPageno():blogPage.getPageno()+1%>">下一页</a> <a href="${pageContext.request.contextPath}/BlogSplitServlet?pageno=<%=blogPage.getTotalpage()%>">尾页</a> <div> 显示从${blogPage.pagenostart+1}到${blogPage.pageno==blogPage.totalpage?blogPage.totalrecord:blogPage.pagesize}, 共${blogPage.totalrecord}条. 每页显示${blogPage.pagesize}条 </div> </div> </div> </body> </html>

这是最后的样子，样式粗略的调了下，功能跟ligerUI默认的分页一模一样

将JSP中代码改为标签（JSTL，需引入相应的jar包）并将JSP中的尾页补白放在servlet中后

servlet中加入

// 尾页填充空白行，若不填充，尾页表格tr行数与前面不一致很难看 List<Blog> list = blogPage.getPagerecord(); if (list.size() < blogPage.getPagesize()) { for (int i = list.size(); i < blogPage.getPagesize(); i++) list.add(null); } blogPage.setPagerecord(list);

jsp页面

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <%@page import="java.util.*,model.Blog,model.BlogPage"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>Insert title here</title> <script type="text/javascript"> //select下拉列表跳转 function selectjump() { var select = document.getElementById("select"); var pageno = select.selectedIndex + 1; window.location.href = "http://localhost/jspPageSplit/BlogSplitServlet" + pageno; } //text跳转，onblur事件，输入框失去焦点时发生 function textjump() { var pageno = document.getElementById("text").value; window.location.href = "http://localhost/jspPageSplit/BlogSplitServlet" + pageno; } </script> </head> <body> <div> <table border="1" cellspacing="0" width="100%" bgcolor="#CEF0C5"> <tr height="40px"> <td>id</td><td>标题</td><td>内容</td><td>创建时间</td> </tr> <c:forEach items="${blogPage.pagerecord}" var="c" varStatus="vs"> <c:if test="${c!=null}"> <tr height="50px"> <td width="10%">${c.id}</td> <td width="20%">${c.title}</td> <td width="40%">${c.content}</td> <td width="30%">${c.created_time}</td> </tr> </c:if> <> <c:if test="${c==null}"> <tr height="50px"> <td width="10%"></td> <td width="20%"></td> <td width="40%"></td> <td width="30%"></td> </tr> </c:if> </c:forEach> </table> <div> <> <select id="select"> <c:forEach begin="1" end="${blogPage.totalpage}" var="i"> <option value="${i}" ${blogPage.pageno==i"selected"':''}>${i}</option> </c:forEach> </select> <a href="${pageContext.request.contextPath}/BlogSplitServlet">首页</a> <a href="${pageContext.request.contextPath}/BlogSplitServlet?pageno=${blogPage.pageno-1<1?blogPage.pageno:blogPage.pageno-1}">上一页</a> <input type="text" id="text" size="1px" value="${blogPage.pageno}" onblur="textjump()">/${blogPage.totalpage} <a href="${pageContext.request.contextPath}/BlogSplitServlet?pageno=${blogPage.pageno+1>blogPage.totalpage?blogPage.pageno:blogPage.pageno+1}">下一页</a> <a href="${pageContext.request.contextPath}/BlogSplitServlet?pageno=${blogPage.totalpage}">尾页</a> <div> 显示从${blogPage.pagenostart+1}到${blogPage.pageno==blogPage.totalpage?blogPage.totalrecord:blogPage.pagesize}, 共${blogPage.totalrecord}条. 每页显示${blogPage.pagesize}条 </div> </div> </div> </body> </html>

实际运用中可以根据需求编写jsp页面，但是后台代码基本是通用的

javabean servlet jsp实现分页功能代码解析4