JavaWeb分頁技術（jsp+servlet+dao+javabean）

記錄整理期末實訓項目中的分頁功能實現，以備不時之需，直接上代碼：

0.建表（準備測試數據）

/*
Navicat MySQL Data Transfer
Date: 2019-12-24 15:21:58
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for books
-- ----------------------------
DROP TABLE IF EXISTS `books`;
CREATE TABLE `books` (
  `id` varchar(200) NOT NULL,
  `name` varchar(100) NOT NULL,
  `price` double DEFAULT NULL,
  `pnum` int(11) DEFAULT NULL,
  `category` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of books
-- ----------------------------
INSERT INTO `books` VALUES ('1001', 'java編程思想', '98', '100', '計算機');
INSERT INTO `books` VALUES ('1002', '西遊記', '10', '50', '文學');
INSERT INTO `books` VALUES ('1003', '九陰真經', '20', '30', '武俠');
INSERT INTO `books` VALUES ('1004', '365夜睡前好故事', '19.8', '50', '少兒');
INSERT INTO `books` VALUES ('1006', '三隻小豬', '9.8', '50', '少兒');
INSERT INTO `books` VALUES ('1007', '中華上下五千年', '28', '100', '少兒');
INSERT INTO `books` VALUES ('1008', '三國演義', '9.8', '50', '文學');

1.DBUtil（數據庫連接封裝類）

package com.ambow.util;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Connection;  
import java.sql.PreparedStatement;  
import java.sql.Statement;  
public class DBUtil {
    private static String driver = "com.mysql.jdbc.Driver";
    private static String url = "jdbc:mysql://localhost:3306/bookstore";
    private static String username = "root";
    private static String password = "root";
    static {
        try {
            /**
             * 加載驅動
             */
            Class.forName(driver);
        }catch(Exception ex) {
            ex.printStackTrace();
        }
    }
    public static Connection getConnection() {
        /**
         * 創建連接對象
         */
        Connection conn=null;
        try {
            conn=(Connection) DriverManager.getConnection(url,username,password);
        }catch(Exception ex) {
            ex.printStackTrace();
        }
        return conn;
    }
    /**
     * 關閉相關流
     */
    public static void close(ResultSet rs,Statement st,Connection conn) {
        try {
            if(rs!=null) {
                rs.close();
            }
            if(st!=null) {
                st.close();
            }
            if(conn!=null) {
                conn.close();
            }
        }catch(SQLException e) {
            e.printStackTrace();
        }
    }
    public static void closePst(ResultSet rs,PreparedStatement pst,Connection conn) {
        try {
            if(rs!=null) {
                rs.close();
            }
            if(pst!=null) {
                pst.close();
            }
            if(conn!=null) {
                conn.close();
            }
        }catch(SQLException e) {
            e.printStackTrace();
        }
    }


}

2.Book（實體類）

package com.ambow.domain;

public class Book {
    private int id;
    private String name;
    private float price;
    private int pnum;
    private String category;

    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 float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        this.price = price;
    }

    public int getPnum() {
        return pnum;
    }

    public void setPnum(int pnum) {
        this.pnum = pnum;
    }

    public String getCategory() {
        return category;
    }

    public void setCategory(String category) {
        this.category = category;
    }
}

3.PageModel（分頁模型類）

package com.ambow.domain;

import java.util.List;  

/** 
 * 封裝分頁信息 
 * @author Administrator 
 * 
 */  
public class PageModel<E> {  
    //結果集  
    private List<E> list;  
    //查詢記錄數  
    private int totalRecords;   
    //每頁多少條數據  
    private int pageSize;  
    //第幾頁  
    private int pageNo;  
      
    /** 
     * 總頁數 
     * @return 
     */  
    public int getTotalPages() {  
        return (totalRecords + pageSize - 1) / pageSize;  
    }  
      
    /** 
     * 取得首頁 
     * @return 
     */  
    public int getTopPageNo() {  
        return 1;  
    }  
      
    /** 
     * 上一頁 
     * @return 
     */  
    public int getPreviousPageNo() {  
        if (pageNo <= 1) {  
            return 1;  
        }  
        return pageNo - 1;  
    }  
      
    /** 
     * 下一頁 
     * @return 
     */  
    public int getNextPageNo() {  
        if (pageNo >= getBottomPageNo()) {  
            return getBottomPageNo();  
        }  
        return pageNo + 1;    
    }  
      
    /** 
     * 取得尾頁 
     * @return 
     */  
    public int getBottomPageNo() {  
        return getTotalPages();  
    }  
    /**
     * get set函數  
     * @return
     */
    public List<E> getList() {  
        return list;  
    }  
  
    public void setList(List<E> list) {  
        this.list = list;  
    }  
  
    public int getTotalRecords() {  
        return totalRecords;  
    }  
  
    public void setTotalRecords(int totalRecords) {  
        this.totalRecords = totalRecords;  
    }  
  
    public int getPageSize() {  
        return pageSize;  
    }  
  
    public void setPageSize(int pageSize) {  
        this.pageSize = pageSize;  
    }  
  
    public int getPageNo() {  
        return pageNo;  
    }  
  
    public void setPageNo(int pageNo) {  
        this.pageNo = pageNo;  
    }  
}

4.BookDao（業務邏輯層，操作數據庫等操作，返回值爲PageModel對象）

package com.ambow.dao;

import java.sql.Connection;  
import java.sql.PreparedStatement;  
import java.sql.ResultSet;  
import java.sql.SQLException;  
import java.util.ArrayList;  
import java.util.List;

import com.ambow.domain.Book;
import com.ambow.domain.PageModel;
import com.ambow.util.DBUtil;
  
public class BookDao {
    public PageModel<Book> findData(String pageNo, String pageSize){
        PageModel<Book> pageModel=null;
        Connection conn= DBUtil.getConnection();
        String sql="select * from books limit ?,?";
        PreparedStatement pst=null;  
        ResultSet rs=null;
        Book rec=null;
        List<Book> list=new ArrayList<Book>();
        try {  
              pst=conn.prepareStatement(sql); 
              //pstm.setInt(1, (pageNo-1)*pageSize); 
              //pstm.setInt(2, pageNo*pageSize);
              pst.setInt(1, (Integer.parseInt(pageNo)-1)*Integer.parseInt(pageSize));  
              pst.setInt(2, Integer.parseInt(pageSize));  
              rs=pst.executeQuery();
              while(rs.next()){  
                  rec=new Book();
                  rec.setId(rs.getInt("id"));  
                  rec.setName(rs.getString("name"));
                  rec.setPrice(rs.getFloat("price"));
                  rec.setPnum(rs.getInt("pnum"));
                  rec.setCategory(rs.getString("category"));
                  list.add(rec);
               }  
               ResultSet rs2=pst.executeQuery("select count(*) from books");
               int total=0;  
               if(rs2.next()){  
                   total=rs2.getInt(1);//總的數據條數 
               }  
                pageModel=new PageModel<Book>();
                pageModel.setPageNo(Integer.parseInt(pageNo));  
                pageModel.setPageSize(Integer.parseInt(pageSize));  
                pageModel.setTotalRecords(total);  
                pageModel.setList(list); 
            } catch (SQLException e) {  
                e.printStackTrace();  
            }finally{  
               DBUtil.closePst(rs, pst, conn);
            } 
        return pageModel;  
    }  
      
    public static void main(String[] args) {
        BookDao client=new BookDao();
        PageModel<Book> pageModel=client.findData("2","4");
        List<Book> list=pageModel.getList();
        for(Book a:list){
            System.out.print("ID:"+a.getId()+",名稱:"+a.getName()+",價格:"+a.getPrice());
            System.out.println();  
        }  
        System.out.print("當前頁:"+pageModel.getPageNo()+" ");  
        System.out.print("共"+pageModel.getTotalPages()+"頁  ");  
        System.out.print("首頁:"+pageModel.getTopPageNo()+" ");  
        System.out.print("上一頁:"+pageModel.getPreviousPageNo()+" ");  
        System.out.print("下一頁:"+pageModel.getNextPageNo()+" ");  
        System.out.print("尾頁:"+pageModel.getBottomPageNo()+" ");  
        System.out.print("共"+pageModel.getTotalRecords()+"條記錄");  
        System.out.println();  
    }
  
}

5.BookServlet（控制層，servlet，連接前端和業務層，獲得PageModel對象後跳轉到新頁面展示分頁數據信息）

package com.ambow.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.ambow.dao.BookDao;
import com.ambow.domain.Book;
import com.ambow.domain.PageModel;


/**
 * Servlet implementation class recomment
 */
@WebServlet("/getBook")
public class BookServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        String pageSize = request.getParameter("pageSize");// 每頁顯示行數
        String pageNo = request.getParameter("pageNo");// 當前顯示頁次
        if (pageSize == null) {// 爲空時設置默認頁大小爲10
            pageSize = "10";
        }
        if (pageNo == null) {// 爲空時設置默認爲第1頁
            pageNo = "1";
        }
        //System.out.println("pageNo="+pageNo+"pageSize="+pageSize);
        // 保存分頁參數，傳遞給下一個頁面
        request.setAttribute("pageSize", pageSize);
        request.setAttribute("pageNo", pageNo);
        //新建Dao對象，獲取pageModel
        BookDao client=new BookDao();
        PageModel<Book> pageModel=client.findData(pageNo,pageSize);
        request.setAttribute("pageModel", pageModel);//前端獲取這個值
        request.getRequestDispatcher("result.jsp").forward(request, response);
    }

}

6.index.jsp（程序入口，調到servlet層）

<%@ page language="java" contentType="text/html; charset=utf-8"
         pageEncoding="utf-8"%>
<!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=ISO-8859-1">
  <title>Insert title here</title>
</head>
<body>
<a href="${pageContext.request.contextPath}/getBook">查看所有圖書信息</a>
</body>
</html>

7.result.jsp（展示分頁結果的頁面）

<%@ page language="java" contentType="text/html; charset=utf-8"
         pageEncoding="utf-8"%>
<%@ page import="java.util.*" %>
<%@ page import="com.ambow.domain.Book" %>
<%@ page import="com.ambow.domain.PageModel" %>

<%
    String pageSize = (String) request.getAttribute("pageSize");
    String pageNo = (String) request.getAttribute("pageNo");
    PageModel<Book> pageModel=(PageModel<Book>) request.getAttribute("pageModel");
    List<Book> list=pageModel.getList();
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <!-- <script src="/haha/js/jquery.min.js" type="text/javascript"></script> -->
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <title>Insert title here</title>
    <style type="text/css">
        table{
            width: 60%;
            margin: auto;
            border: solid 1px sandybrown;
        }
        caption{
            font-weight: bold;
            font-size: 24px;
        }
        #dataTable td{
            border: solid 1px sandybrown;
        }
        #pageTable{
            margin-top: 10px;
        }
    </style>
</head>
<body>
<table id="dataTable">
    <caption>所有信息</caption>
    <tr align="center">
        <td><b>ID</b></td>
        <td><b>圖書名稱</b></td>
        <td><b>圖書價格</b></td>
        <td><b>圖書數量</b></td>
        <td><b>圖書類別</b></td>
    </tr>

    <%
        if(list==null||list.size()<1){
    %><p align="center">還沒有任何數據！</p>
    <%}else{
        for(Book rec:list){
    %>
    <tr>
        <td><%=rec.getId() %></td>
        <td><%=rec.getName() %></td>
        <td><%=rec.getPrice() %></td>
        <td><%=rec.getPnum() %></td>
        <td><%=rec.getCategory() %></td>
    </tr>
    <%
            }
        }
    %>

</table>
<form name="form1" action="${pageContext.request.contextPath}/getBook" method="post">
    <TABLE id="pageTable">
        <TR>
            <TD align="left">
                共<%=pageModel.getTotalRecords()%>條/<a>每頁</a>
                <select name="pageSize"
                        onchange="document.all.pageNo.value='1';document.all.form1.submit();">
                    <option value="5" <%if(pageSize.equals("5")){%>
                            selected="selected" <%}%>>5</option>
                    <option value="10" <%if(pageSize.equals("10")){%>
                            selected="selected" <%}%>>10</option>
                    <option value="20" <%if(pageSize.equals("20")){%>
                            selected="selected" <%}%>>20</option>
                    <option value="30" <%if(pageSize.equals("30")){%>
                            selected="selected" <%}%>>30</option>
                </select>條</TD>
            <TD align="right">
                <a href="javascript:document.all.pageNo.value='<%= pageModel.getTopPageNo() %>';document.all.form1.submit();">首頁</a>
                <a href="javascript:document.all.pageNo.value='<%= pageModel.getPreviousPageNo() %>';document.all.form1.submit();">上一頁</a>
                <a href="javascript:document.all.pageNo.value='<%= pageModel.getNextPageNo()%>';document.all.form1.submit();">下一頁</a>
                <a href="javascript:document.all.pageNo.value='<%= pageModel.getBottomPageNo()%>';document.all.form1.submit();">尾頁</a>
                <a>第</a>
                <select name="pageNo" onchange="document.all.form1.submit();">
                    <%
                        int pageCount = pageModel.getTotalPages();
                    %>
                    <%
                        for (int i = 1; i <= pageCount; i++) {
                    %>
                    <option value="<%=i%>" <%if(pageNo.equals(i+"")){%>
                            selected="selected" <%}%>><%=i%></option>
                    <%
                        }
                    %>
                </select><a>頁</a>/共<%=pageModel.getTotalPages()%>頁</TD>
        </TR>
    </TABLE>

</form>
</body>
</html>

9.展示效果

項目源碼：下載地址