javabean servlet jsp实现分页功能代码解析

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：） 

模拟实现过程： 

目录结构

 

数据库（mysql）

 

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="
    + 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="
    + 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 style="width: 50%; height: 400px">
  <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>
   <!-- 尾页空白行填充 -->
   <%} else {%>
   <tr height="50px">
    <td width="10%"></td>
    <td width="20%"></td>
    <td width="40%"></td>
    <td width="30%"></td>
   </tr>
   <%}}%>
  </table>
  <div style="height:50px;background-color: #4b7db3;line-height: 40px;">
    
  <!-- select下拉框 -->
  <select id="select">
   <%for (int i = 1; i <= blogpage.gettotalpage(); i++) {%>
   <option onclick="selectjump()"><%=i%></option>
   <%}%>
  </select> 
  <a href="${pagecontext.request.contextpath}/blogsplitservlet?pageno=1">首页</a>
  <a href="${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 style="float: right;">
  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="
    + 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="
    + pageno;
 }
</script>
</head>
<body>
 <div style="width: 50%; height: 400px">
  <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>
   <!-- 尾页空白行填充 -->
   <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 style="height:50px;background-color: #4b7db3;line-height: 40px;">
    
  <!-- select下拉框 -->
  <select id="select">
  <c:foreach begin="1" end="${blogpage.totalpage}" var="i">
  <option value="${i}" onclick="selectjump()" ${blogpage.pageno==i?'selected="selected"':''}>${i}</option>
  </c:foreach>
  </select> 
  <a href="${pagecontext.request.contextpath}/blogsplitservlet?pageno=1">首页</a>
  <a href="${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=${blogpage.totalpage}">尾页</a>
  <div style="float: right;">
  显示从${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 

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。