(jsp 和 servlet功能篇) jsp+servlet+javaBean 实现分页代码（mysql 数据库）

- 日理万妓 2023-10-18 22:07 126阅读 0赞

实例代码：

JavaBean
    
    package Bean;
    //物品类
    public class Goods
    {
     private int goodsid;  // 物品编号
     public String goodsname;   // 物品名称
     private float price;        // 物品单件
    
     public void setGoodsid(int goodsid)
     {
      this.goodsid = goodsid;
     }
     public int getGoodsid()
     {
      return goodsid;
     }
     // 物品名称
     public void setGoodsname(String goodsname)
     {
      this.goodsname = goodsname;
     }
     public String getGoodsname()
     {
      return goodsname;
     }
     // 物品价格
     public void setPrice(float price)
     {
      this.price = price;
     }
     public float getPrice()
     {
      return price;
     }
    }

数据库（单列模式）

单例类
    
    package util;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    
    public class DbConnection {
     private static Connection conn=null;
     private String driver="com.mysql.jdbc.Driver";
     private String url="jdbc:mysql://localhost:3306/mydata";
     private String user="root";
     private String password="1234567";
     
     private DbConnection(){
      try {
       Class.forName(driver);
       conn=DriverManager.getConnection(url, user, password);
      } catch (ClassNotFoundException e) {
       e.printStackTrace();
      } catch (SQLException e) {
       e.printStackTrace();
      }
     }
     
     public static Connection getConnection() {
      if(conn==null){
       new DbConnection();
      }
      return conn;
     }
    }

数据库操作逻辑代码：

数据库访问实现
    
    package DAO;
    
    import java.sql.Connection;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.ArrayList;
    
    import Bean.Goods;
    
    import util.DbConnection;
    
    public class Dao {
     private static Connection conn;
     private static ResultSet rs;
     private static Statement stmt;
     private static int pagesize=5;
     static{
      conn=DbConnection.getConnection();
     }
     
     //通用的查询方法
     public static ResultSet ExecuteQuery(String sql) {
      try {
       stmt=conn.createStatement();
       rs=stmt.executeQuery(sql);
      } catch (SQLException e) {
       e.printStackTrace();
      }
      return rs;
     }
     
     //分页逻辑
     public static ArrayList<Goods> getGoodsList(int currentpageno){
      ArrayList<Goods> GoodsList=new ArrayList<Goods>();
      int BeginRecord=(currentpageno-1)*pagesize;
      int EndRecord=currentpageno*pagesize;
      rs=ExecuteQuery("select * from goods limit "+BeginRecord+","+EndRecord);
      try {
       while(rs.next()){
        Goods goods=new Goods();
        goods.setGoodsid(rs.getInt(1));
        goods.setGoodsname(rs.getString(2));
        goods.setPrice(rs.getFloat(3));
        GoodsList.add(goods);
       }
      } catch (SQLException e) {
       e.printStackTrace();
      }
      return GoodsList;
     }
     
     //统计记录数
     public static int getPageCount(){
      int total=0;
      int PageCount=0;
      rs=ExecuteQuery("select count(*) from goods");
      try {
       if(rs.next()){
        total=rs.getInt(1);
        PageCount=(total-1)/pagesize+1;
       }
      } catch (SQLException e) {
       e.printStackTrace();
      }
      return PageCount;
     }
    }

servlet控制器

servlet控制器
    
    package servlet;
    
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.util.ArrayList;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import Bean.Goods;
    import DAO.Dao;
    
    public class GetLimiteGoods extends HttpServlet {
     private static final long serialVersionUID = 1L;
     public void doGet(HttpServletRequest request, HttpServletResponse response)
       throws ServletException, IOException {
      response.setContentType("text/html");
      String pageno= request.getParameter("currentpageno");
      int currentpageno=1;
      if(pageno!=null){
       currentpageno=Integer.parseInt(pageno);
      }
      ArrayList<Goods> GoodsList=Dao.getGoodsList(currentpageno);
      request.setAttribute("GoodsList", GoodsList);
      request.setAttribute("currentpageno", currentpageno);
      request.setAttribute("PageCount", Dao.getPageCount());
      request.getRequestDispatcher("/LimiteGoods.jsp").forward(request, response);
     }
    
     public void doPost(HttpServletRequest request, HttpServletResponse response)
       throws ServletException, IOException {
               doGet(request,rsponse);
     }
    }

配置文件

xml配置：
    
    <?xml version="1.0" encoding="UTF-8"?>
    <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
     http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
      <servlet>
        <description>This is the description of my J2EE component</description>
        <display-name>This is the display name of my J2EE component</display-name>
        <servlet-name>GetLimiteGoods</servlet-name>
        <servlet-class>servlet.GetLimiteGoods</servlet-class>
      </servlet>
    
      <servlet-mapping>
        <servlet-name>GetLimiteGoods</servlet-name>
        <url-pattern>/servlet/GetLimiteGoods</url-pattern>
      </servlet-mapping>
    </web-app>

jsp代码：

表现层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 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>
     </head>
     <body>
     <center>
     <c:if test="${currentpageno>=1}">
       <a href="GetLimiteGoods?currentpageno=1">首页</a>
       <a href="GetLimiteGoods?currentpageno=${currentpageno-1}">上一页</a>
      </c:if>
      <c:if test="${currentpageno==1}">
       <a href="GetLimiteGoods?currentpageno=${currentpageno+1}">下一页</a>
       <a href="GetLimiteGoods?currentpageno=${PageCount}">尾页</a>
      </c:if>
      <table width="80%" border="1" height="56">
       <tr align="center">
        <td>
         商品编号
        </td>
        <td>
         商品名称
        </td>
        <td>
         商品价格
        </td>
       </tr>
       <c:forEach var="goods" items="${GoodsList}">
        <tr align="center">
         <td>
          ${goods.goodsid}
         </td>
         <td>
          ${goods.goodsname}
         </td>
         <td>
          ${goods.price}
         </td>
        </tr>
       </c:forEach>
      </table>
      </center>
     </body>
    </html>