Jsp的分页操作源代码

 
一  分页操作的分析：

1．层的问题

    Com.csdn.domaim

    Com.csdn.dao

    Com.csdn.daoImpl

    Com.csdn.service 接口

    Com.csdn.serviceImpl 实现类

    Com.csdn.web 控制器

    Com.csdn.web.filter

    Com.csdn.web.listener

    Com.csdn.util

 

2．如何实现的问题

    StuentBean中定义了几个私有的属性：   id  name   age  address  

    StudentDao接口用于实现对数据库中属性的封装。

    StudntService接口：定义方法，用数据库处理的方法

    StudentServicImpl实现类

    ControllerService：控制器：接收客户端的请求

    List.jsp  显示所有的信息

 

3．分页显示：

    首先先检查是否与数据库连接，可以先把所有的都输出。

    然后要点击浏览器中的超链接来获取从数据库中读取的数据并显示，在超链接的时候要传参数，通过对servlet层的访问，在servlet层中对从数据库中的数据进行读取之后，通过判断再把参数传给浏览器并显示从数据库中调用的数据

二   代码的实现和说明

1．首先创建数据库，如图：

并从数据库中插入数据

2．在java中把数据库中的数据封装成类  StudentBean.java

public class StudentBean {
    private int id;
    private String name;
    private int age;
    private String address;
    public StudentBean() {
       super();
       // TODO Auto-generated constructor stub
    }
    public StudentBean(int id, String name,int age, String address) {
       super();
       this.id = id;
       this.name = name;
       this.age = age;
       this.address = address;
    }
    public int getId() {
       return id;
    }
    public void setId(int id) {
       this.id = id;
    }
    public String getName() {
       return name;
    }
    public void setName(String name) {
       this.name = name;
    }
    public int getAge() {
       return age;
    }
    public void setAge(int age) {
       this.age = age;
    }
    public String getAddress() {
       return address;
    }
    public void setAddress(String address) {
       this.address = address;
    }
    @Override
    public String toString() {
       return "StudentBean [address=" + address + ", age=" + age + ", id="
              + id + ", name=" + name + "]";
    }
   
}
3.创建实现对数据库数据的查找和分页的查找，首先先创建一个dao层，并在dao层写上一个接口和一个daoImpl两个java类，接口是为了在service层中与servetl成的连接，首先创建StudentDao.java

import java.util.List;

import com.hbsi.domain.StudentBean;

public interface StudentDao {

    //返回所有记录行

    public List<StudentBean> findAll();

    //返回指定页中显示的记录行（一共有多少页，共多长）

    public List<StudentBean> listPage(int currentPage,int pageSize);

    //返回所有记录的行数

    public int getSize();

}

再创建实现类  StudentDaoImpl.java

package com.hbsi.dao;

 

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.LinkedList;

import java.util.List;

 

import com.hbsi.domain.StudentBean;

//接口的实现类

public class StudentDaoImpl implements StudentDao {

 

    //声明操作的数据库对象

    private static Connection conn;

    private PreparedStatement pstmt;

    private ResultSet rs;

   

    //第一步：准备驱动程序，构造到项目路径中

    private static final String URL="jdbc:mysql://localhost:3306/demo?user=root&password=qiao&useUnicode=true&characterEncoding=utf8";

   

    static{

       try {

           //第二步：加载驱动程序

           Class.forName("com.mysql.jdbc.Driver");

           //第三步:获取连接对象

           conn = DriverManager.getConnection(URL);

       } catch (ClassNotFoundException e) {

           // TODO Auto-generated catch block

           e.printStackTrace();

       } catch (SQLException e) {

           // TODO Auto-generated catch block

           e.printStackTrace();

       }

    }

   

    private int size;//记录多少行

    public List<StudentBean> findAll() {

       //存放读取的数据

       List<StudentBean> list = new LinkedList<StudentBean>();

       try {

           pstmt = conn.prepareStatement("select * from student");

           rs = pstmt.executeQuery();

           //从结果集中读取

           while(rs.next()){

              StudentBean s = new StudentBean();

              s.setId(rs.getInt(1));

              s.setName(rs.getString(2));

              s.setAge(rs.getInt(3));

              s.setAddress(rs.getString(4));

              list.add(s);

           }

       } catch (SQLException e) {

           // TODO Auto-generated catch block

           e.printStackTrace();

       }

       size=list.size();

       return list;

    }

 

    //获取总的记录行数

    public int getSize() {

       // TODO Auto-generated method stub

       findAll();

       return size;

    }

 

    //截取的读取

    public List<StudentBean> listPage(int currentPage, int pageSize) {

       //存放读取的数据

       List<StudentBean> list = new LinkedList<StudentBean>();

       try {

           //记录行

           int recordIndex=(currentPage-1)*pageSize;

           pstmt = conn.prepareStatement("select * from student limit ?,?");

           int index =1;

           pstmt.setInt(index++, recordIndex);

           pstmt.setInt(index++, pageSize);

 

           //从结果集中读

           rs = pstmt.executeQuery();

           while(rs.next()){

              StudentBean s = new StudentBean();

              s.setId(rs.getInt(1));

              s.setName(rs.getString(2));

              s.setAge(rs.getInt(3));

              s.setAddress(rs.getString(4));

              list.add(s);

           }

       } catch (SQLException e) {

           // TODO Auto-generated catch block

           e.printStackTrace();

       }

       return list;

    }

 

}

4.service层是业务层，是是和其他接口的层

首先创建StudentService.java

package com.hbsi.service;

 

import java.util.List;

 

import com.hbsi.domain.StudentBean;

 

public interface StudentService {

    public List<StudentBean> findAll();

    public List<StudentBean> listPage(int currentPage,int pageSzie);

    //得到所有的记录行

    public int getSize();

}

再创建StudentserviceImpl.java

 

package com.hbsi.service;

 

import java.util.List;

 

import com.hbsi.dao.StudentDaoImpl;

import com.hbsi.domain.StudentBean;

 

public class StudentServceImpl implements StudentService {

 

    StudentDaoImpl dao = new StudentDaoImpl();

   

    public List<StudentBean> findAll() {

       // TODO Auto-generated method stub

       return dao.findAll();

    }

 

    public List<StudentBean> listPage(int currentPage, int pageSize) {

       // TODO Auto-generated method stub

       return dao.listPage(currentPage, pageSize);

    }

 

    public int getSize() {

       // TODO Auto-generated method stub

       return dao.getSize();

    }

 

}

5.jsp页面的实现  list.jsp

    <%@ page language="java" import="java.util.*,com.hbsi.domain.*"
    pageEncoding="utf-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
           + request.getServerName() + ":" + request.getServerPort()
           + path + "/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
       <base href="<%=basePath%>">
 
       <title>My JSP 'list.jsp' starting page</title>
 
       <meta http-equiv="pragma" content="no-cache">
       <meta http-equiv="cache-control" content="no-cache">
       <meta http-equiv="expires" content="0">
       <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
       <meta http-equiv="description" content="This is my page">
       <!--
    <link rel="stylesheet" type="text/css"
href="styles.css">
    -->
 
    </head>
 
    <body>
       <!-- 读取集合中 的数据 -->
       <%
           List<StudentBean> list = (List<StudentBean>) request.getAttribute("list");
           int pageNo = Integer.parseInt(request.getParameter("pageNo"));
       %>
       <h3>
           学生信息表
       </h3>
       <!-- 读取 -->
       <table>
       <%
           for (int i = 0; i < list.size(); i++) {
       %>
 
       <tr>
           <td><%=list.get(i).getId() %></td>
           <td><%=list.get(i).getName() %></td>
           <td><%=list.get(i).getAge()%></td>
           <td><%=list.get(i).getAddress() %></td>
       </tr>
       <%
           }
       %>
   
 
       </table><br/>
       <a href="listStudent?pageNo=1">第一页</a> <a href="listStudent?pageNo=<%=pageNo-1 %>">上一页</a> <a href="listStudent?pageNo=<%=pageNo+1 %>">下一页</a> <a href="">最后页</a>
    </body>
</html>
6.servlet层的实现  ControllerServlet.java

package com.hbsi.web;

 

import java.io.IOException;

import java.util.List;

 

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import com.hbsi.domain.StudentBean;

import com.hbsi.service.StudentServceImpl;

 

public class ControllerServlet extends HttpServlet {

 

    /**

     *

     */

    private static final long serialVersionUID = 1L;

 

    public ControllerServlet() {

       super();

    }

 

    public void destroy() {

       super.destroy(); // Just puts "destroy" string in log

       // Put your code here

    }

 

    public void doGet(HttpServletRequest request, HttpServletResponse response)

           throws ServletException, IOException {

 

       doPost(request, response);

    }

 

    public void doPost(HttpServletRequest request, HttpServletResponse response)

           throws ServletException, IOException {

       // 通过服务层得到数据

       StudentServceImpl service = new StudentServceImpl();

       // List<StudentBean> list = service.findAll();

 

       // 分页的操作

       // 计算一下一共有多少页

       int total = service.getSize();// 一共有多少行记录

       int pageSize = 3;// 每页显示的记录行数

       int totalPages = total / pageSize;//共有多少个页面显示

       totalPages = (total % pageSize == 0) ? totalPages : totalPages + 1;// 总共有total页

      

       //显示的页数

       int currentPage = 1;

       if (request.getParameter("pageNo") != null) {

           currentPage = Integer.parseInt(request.getParameter("pageNo"));

       }

       if (currentPage < 1) {

           currentPage = 1;

       }

       if(currentPage>totalPages){

           currentPage=totalPages;

       }

      

       List<StudentBean> list =service.listPage(currentPage, pageSize);

       // servlt和jsp的桥梁,设置作用域的范围

       request.setAttribute("list", list);

 

       // 通过jsp页面显示所有的数据,请求的转向

       RequestDispatcher rd = request.getRequestDispatcher("list.jsp?pageNo="+currentPage);

       rd.forward(request, response);

 

    }

 

    public void init() throws ServletException {

       // Put your code here

    }

}

 

 

这样简单的分页就做好了，大家好好看看吧！！本人是jsp的初学者，希望多多指点！