如何用jsp+mysql实现网页的分页查询-编程学习网

本篇内容介绍了“如何用jsp+mysql实现网页的分页查询”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！

一、实现分页查询的核心sql语句

（1）查询数据库的记录总数的sql语句：

select count(*) from +（表名）;

（2）每次查询的记录数的sql语句：

其中：0是搜索的索引，2是每次查找的条数。

select * from 表名 limit 0,2;

二、代码实现

*上篇写过这两个类， DBconnection类：用于获取数据库连接，Author对象类。这两个类的代码点击连接查看。点击链接查看 DBconnection类和Author对象类

（1）登录页面：index.jsp。

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%><!DOCTYPE html><html><head><meta charset="utf-8"><title>Insert title here</title></head><body>    <a href="AuthorListPageServlet">用户列表分页查询</a></body></html>

（2）显示页面：userlistpage.jsp。

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html><html><head><meta charset="utf-8"><title>查询页面</title></head><body><table border="1">  <tr>    <td>编号</td>    <td>名称</td>    <td>价格</td>    <td>数量</td>    <td>日期</td>    <td>风格</td>  </tr>  <c:forEach items="${pageBean.list}" var="author">  <tr>    <td>${author.id}</td>    <td>${author.name }</td>    <td>${author.price }</td>    <td>${author.num }</td>    <td>${author.dates}</td>    <td>${author.style}</td>  </tr>  </c:forEach></table><c:if test="${ pageBean.record>0}"><div>            <c:if test="${pageBean.currentPage <= 1}">      <span>首页</span>      <span>上一页</span>      <a href ="AuthorListPageServlet?currPage=${pageBean.currentPage + 1 }">下一页</a>      <a href ="AuthorListPageServlet?currPage=${pageBean.totalPage }">尾页</a>      </c:if>            <c:if test="${pageBean.currentPage > 1 && pageBean.currentPage < pageBean.totalPage  }">       <a href ="AuthorListPageServlet?currPage=1">首页</a>      <a href ="AuthorListPageServlet?currPage=${pageBean.currentPage - 1 }">上一页</a>      <a href ="AuthorListPageServlet?currPage=${pageBean.currentPage + 1 }">下一页</a>      <a href ="AuthorListPageServlet?currPage=${pageBean.totalPage }">尾页</a>      </c:if>          <c:if test="${ pageBean.currentPage >= pageBean.totalPage}">      <a href ="AuthorListPageServlet?currPage=1">首页</a>      <a href ="AuthorListPageServlet?currPage=${pageBean.currentPage - 1 }">上一页</a>     <span>下一页</span>     <span>尾页</span>     </c:if></div></c:if></body></html>

（3）功能实现：AuthorDao.java。

package com.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.entity.Author;public class AuthorDao {         public  Author check(String username ,int  password ) {                  Author obj = null ;         try {            DBConnection db = new DBConnection();            //获取数据库连接            Connection conn = db.getConn();                        String sql="select *from furnitures where name = ? and id = ?";                        PreparedStatement ps=conn.prepareStatement(sql);            //设置用户名和密码作为参数放入sql语句            ps.setString(1,username);            ps.setInt(2,password);            //执行查询语句            ResultSet rs = ps.executeQuery();            //用户名和密码正确，查到数据  欧式风格  茶几            if(rs.next()) {                obj = new Author();                obj.setId(rs.getInt(1));                obj.setName(rs.getString(2));                obj.setPrice(rs.getInt(3));                obj.setNum(rs.getInt(4));                obj.setDates(rs.getString(5));                obj.setStyle(rs.getString(6));            }        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }         return obj;     }          public List<Author> queryAuthorList(){         Author obj = null ;         List<Author> list = new ArrayList<Author>();         try {            DBConnection db = new DBConnection();            //获取数据库连接            Connection conn = db.getConn();                        String sql="select *from furnitures";                        PreparedStatement ps=conn.prepareStatement(sql);                //执行查询语句            ResultSet rs = ps.executeQuery();            //用户名和密码正确，查到数据  欧式风格  茶几            //循环遍历获取用户信息            while(rs.next()) {                                obj = new Author();                obj.setId(rs.getInt(1));                obj.setName(rs.getString(2));                obj.setPrice(rs.getInt(3));                obj.setNum(rs.getInt(4));                obj.setDates(rs.getString(5));                obj.setStyle(rs.getString(6));                //将对象加入list里边                list.add(obj);            }        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }         return list;     }                    public int queryUserListCount() {         DBConnection db;        try {             db = new DBConnection();             Connection conn = db.getConn();             String sql = "select count(*) from furnitures";                          PreparedStatement ps = conn.prepareStatement(sql);             ResultSet rs = ps.executeQuery();                                       if(rs.next()) {                 return rs.getInt(1);             }                                  } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }                 return 0;     }          public List<Author>queryUserListPage(int pageIndex,int pageSize){                  Author obj = null;         List<Author> list = new ArrayList<Author>();                  try {            Connection conn = new DBConnection().getConn();            String sql = "select * from furnitures limit ?,?;";            PreparedStatement ps = conn.prepareStatement(sql);            ps.setObject(1, pageIndex);            ps.setObject(2,pageSize);                        ResultSet rs = ps.executeQuery();            //遍历结果集获取用户列表数据                        while(rs.next()) {                obj = new Author();                                obj.setId(rs.getInt(1));                obj.setName(rs.getString(2));                obj.setPrice(rs.getInt(3));                obj.setNum(rs.getInt(4));                obj.setDates(rs.getString(5));                obj.setStyle(rs.getString(6));                                list.add(obj);            }        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }         return list;     }          public void add(Author obj) {                try {                        DBConnection db = new DBConnection();            //获取数据库连接            Connection conn = db.getConn();                        String sql="insert into furnitures values(id,?,?,?,?,?)";                        PreparedStatement ps=conn.prepareStatement(sql);            ps.setObject(1, obj.getName());            ps.setObject(2, obj.getPrice());            ps.setObject(3, obj.getNum());            ps.setObject(4,obj.getDates());            ps.setObject(5, obj.getStyle());                        //执行sql语句           ps.execute();                               } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }                 }     //删除用户     public void del(int id) {         try {                                DBConnection db = new DBConnection();                //获取数据库连接                Connection conn = db.getConn();                                String sql="delete from furnitures where id = ?";                                PreparedStatement ps=conn.prepareStatement(sql);                                ps.setObject(1, id);                                //执行sql语句               ps.execute();                                           } catch (SQLException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }                     }    }

（4）交互层：AuthorListPageServlet.java。

package com.servlet;import java.io.IOException;import java.util.List;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.dao.AuthorDao;import com.entity.Author;import com.util.PageBean;@WebServlet("/AuthorListPageServlet")public class AuthorListPageServlet extends HttpServlet {    private static final long serialVersionUID = 1L;               public AuthorListPageServlet() {        super();        // TODO Auto-generated constructor stub    }        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // TODO Auto-generated method stub        int pageSize = 2;        AuthorDao ad = new AuthorDao();        //总记录数        int record = ad.queryUserListCount();        //接收页面传入的页码        String strPage = request.getParameter("currPage");        int currPage = 1;//默认第一页        if(strPage != null) {            currPage = Integer.parseInt(strPage);            }                PageBean<Author> pb = new PageBean<Author>(currPage,pageSize,record);        //查询某一页的结果集        List<Author> list = ad.queryUserListPage(pb.getPageIndex(), pageSize);        pb.setList(list);        request.setAttribute("pageBean", pb);        request.getRequestDispatcher("userlistpage.jsp").forward(request, response);    }        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // TODO Auto-generated method stub        doGet(request, response);    }}

（5）工具类：PageBean.java。作用是：获取结果集。

package com.util;import java.util.List;public class PageBean<T>{    private int currentPage;//当前页码    private int pageIndex;//数据起始索引    private int pageSize;//每页条数            private int record;//总记录数    private int totalPage;//总页数        private List<T>list;//每页显示的结果集        public PageBean(int currentPage,int pageSize,int record) {                this.currentPage = currentPage;        this.pageSize = pageSize;        this.record = record;                //总页数        if(record % pageSize == 0) {            //整除，没有多余的页            this.totalPage = record / pageSize;                    }        else {            //有多余的数据，在增加一页            this.totalPage = record / pageSize + 1;        }                //计算数据起始索引pageIndex        if(currentPage < 1) {            this.currentPage = 1;        }        else if(currentPage > this.totalPage) {            this.currentPage = this.totalPage;        }        this.pageIndex = (this.currentPage -1)*this.pageSize;    }        public int getCurrentPage() {        return currentPage;    }    public void setCurrentPage(int currentPage) {        this.currentPage = currentPage;    }    public int getPageIndex() {        return pageIndex;    }    public void setPageIndex(int pageIndex) {        this.pageIndex = pageIndex;    }    public int getPageSize() {        return pageSize;    }    public void setPageSize(int pageSize) {        this.pageSize = pageSize;    }    public int getRecord() {        return record;    }    public void setRecord(int record) {        this.record = record;    }    public int getTotalPage() {        return totalPage;    }    public void setTotalPage(int totalPage) {        this.totalPage = totalPage;    }    public List<T> getList() {        return list;    }    public void setList(List<T> list) {        this.list = list;    }    }