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：//www.jb51.net/article/92850.htm） 

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 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 getPagerecord() {
  return pagerecord;
 }
 public void setPagerecord(List 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 getPageRecord(int pagenostart, int pagesize) {
  Connection conn = JDBCUtil.getConnection();
  PreparedStatement ps = null;
  ResultSet rs = null;
  String sql = "select * from blog limit ?,?";
  List list = new ArrayList();
  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 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"%>








 <%
  BlogPage blogPage = (BlogPage) request.getAttribute("blogPage");
  List 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);
  }
 %>
 

  
   <%
    for (Blog blog : list) {
     if (blog != null) {
   %>
   
   <%} else {%>
   
   <%}}%>
  

   

    
id
标题
内容
创建时间
   

    
<%=blog.getId()%>
    
<%=blog.getTitle()%>
    
<%=blog.getContent()%>
    
<%=blog.getCreated_time()%>
   
   

    

    

    

    

   
  

    
  
  
   <%for (int i = 1; i <= blogPage.getTotalpage(); i++) {%>
   <%=i%>
   <%}%>
   
  首页
  上一页  
  /${blogPage.totalpage} 
  下一页
  尾页
  

  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
  
  
 

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 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"%>







 

  
   
      
   

   

    
id
标题
内容
创建时间
   
   

    
${c.id}
    
${c.title}
    
${c.content}
    
${c.created_time}
   
   
   
   

    

    

    

    

   
   
   
  
  

    
  
  
  
  ${i}
  
   
  首页
  上一页  
  /${blogPage.totalpage} 
  下一页
  尾页
  

  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
  
  
 

 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脚本之家。