利用MySQL实现分页的web小项目
1、准备工作：
1.1、背景：
以一个网上书城为背景，每页展示5本待售的书籍，展示给用户的内容包括：书籍的名字、作者、售价。要求实现基本的页面跳转功能。
1.2、数据源：
在MySQL中新建一个test的数据库，里面新建一张表，表名：book ，涉及到字段有：id、name、author、price
1.3、需要导入的jar包：
针对MySQL数据库：mysql-connector-java-5.1.7-bin.jar、c3p0-0.9.2.1.jar、mchange-commons-java-0.2.3.4.jar
针对前台页面：jstl-1.0.2.jar、standard-1.0.1.jar（依赖包）
补充：jquery-1.7.2.js（前台jquery使用）、c3p0-config.xml（配置c3p0数据库连接池使用）
2、开发过程
2.1、后台：
2.1.1、Javabeans：Book.java和page.java
下面是Book.java(用来封装关于书籍book的类)
package com.xiaojie.beans;
public class Book {
private Integer id;
private String name;
private String author;
private Integer price;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public Integer getPrice() {
return price;
}
public void setPrice(Integer price) {
this.price = price;
}
@Override
public String toString() {
return "Book [id=" + id + ", name=" + name + ", author=" + author + ", price=" + price + "]";
}
public Book(Integer id, String name, String author, Integer price) {
super();
this.id = id;
this.name = name;
this.author = author;
this.price = price;
}
public Book() {
super();
}
}
package com.xiaojie.beans;
import java.util.List;
public class Page {
private int pageno;
private List books;
private int pagesize=5;
private long totalitemnumner;
public Page(int pageno) {
super();
this.pageno = pageno;
}
public int getPageno() {
if(pageno<0){
pageno=1;
}
if(pageno>getTotalpagenumber()){
pageno=getTotalpagenumber();
}
return pageno;
}
public int getPagesize() {
return pagesize;
}
public void setBooks(List books) {
this.books = books;
}
public List getBooks() {
return books;
}
//得到总共有多少页
public int getTotalpagenumber(){
int totalpagenumber=(int) (totalitemnumner/pagesize);
if(totalitemnumner%pagesize!=0){
totalpagenumber++;
}
return totalpagenumber;
}
public void setTotalitemnumner(long totalitemnumner) {
this.totalitemnumner = (int) totalitemnumner;
}
//判断是否有下一页
public boolean ishasnext(){
if(getPageno()1){
return true;
}
return false;
}
//得到上一页的页码
public int getprevpage(){
if(ishasprev()){
return getPageno()-1;
}
return getPageno();
}
//得到下一页的页码
public int getnextpage(){
if(ishasnext()){
return getPageno()+1;
}
return getPageno();
}
@Override
public String toString() {
return "Page [pageno=" + pageno + ", books=" + books+ ", pagesize=" + pagesize + ", totalitemnumner="
+ totalitemnumner + "]";
}
}
2.1.2、DAO模块：jdbctools、BookDao、Bookimp
jdbctools（获取数据库连接、释放连接）package com.xiaojie.dao;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.DataSource;
import com.mchange.v2.c3p0.ComboPooledDataSource;
public class Jdbctools {
private static DataSource ds=null;
static{
ds=new ComboPooledDataSource("helloc3p0");
}
public static Connection getConnection() throws ClassNotFoundException, SQLException, IOException{
return ds.getConnection();
}
public static void shifanglianjie(Connection ct, PreparedStatement ps,ResultSet rs) {
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(ps!=null){
try {
ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(ct!=null){
try {
ct.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
BookDao(这里我们只需要两个功能：展示所有的books、查询出数据库中究竟有多少条记录)
package com.xiaojie.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import com.xiaojie.beans.Book;
import com.xiaojie.dao.Jdbctools;
public class BookDao {
public List querylist(String sql,Object...args){
Book book=null;
Connection ct=null;
PreparedStatement ps=null;
ResultSet rs=null;
Listbooks=new ArrayList();
try {
ct=Jdbctools.getConnection();
System.out.println("获取到连接了");
ps=ct.prepareStatement(sql);
for(int i=0;i Bookimp（传sql 语句等参数以实现BookDao里的两大功能）
package com.xiaojie.dao;
import java.util.ArrayList;
import java.util.List;
import com.xiaojie.beans.Book;
public class Bookimp extends BookDao{
public Listgetbooks(int pageno,int pagesize){
String sql="select * from book limit ?,?";
return querylist(sql, (pageno-1)*5,5);
}
public long getTotalBookNumber() {
String sql="select count(id) from book ";
return getForValue(sql);
}
}
2.1.3、service模块：BookService(业务部分)
BookService的作用是：用页码（pageno）、当前要展示的书籍（books）、总共有多少本书（totalitemnumner）封装成一个page对象。即这个page对象要携带它本该具备的所有属性的值。这样的目的就是为了，便于将来servlet调用后展示在前台页面。package com.xiaojie.service;
import com.xiaojie.beans.Page;
import com.xiaojie.dao.Bookimp;
public class BookService {
private Bookimp bookimp=new Bookimp();
public Page getpage(int pageno){
Page page=new Page(pageno);
page.setBooks(bookimp.getbooks(pageno, 5));
page.setTotalitemnumner(bookimp.getTotalBookNumber());
System.out.println(page+"service");
return page;
}
}
2.1.4、servlet模块：PageServlet(控制器部分)
package com.xiaojie.servlet;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.ArrayList;
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.xiaojie.beans.Book;
import com.xiaojie.beans.Page;
import com.xiaojie.service.BookService;
/**
* Servlet implementation class PageServlet
*/
@WebServlet("/pageservlet")
public class PageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String methodname=request.getParameter("method");
try {
Method method=getClass().getDeclaredMethod(methodname,HttpServletRequest.class,HttpServletResponse.class);
method.invoke(this, request,response);//调用各自的方法
} catch (Exception e) {
e.printStackTrace();
}
}
private BookService bookservice=new BookService();
protected void getpage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("getpage进来了");
String pagenoStr=request.getParameter("pageno");
int pageno=1;
try {
pageno=Integer.parseInt(pagenoStr);
} catch (Exception e) {
// TODO: handle exception
}
Page page=new Page(pageno);
page=bookservice.getpage(pageno);
request.setAttribute("bookpage", page);
request.getRequestDispatcher("/WEB-INF/pages/page.jsp").forward(request, response);
}
}
2.2、前台：
index.jsp(启动控制器servlet)
<% response.sendRedirect(request.getContextPath()+"/pageservlet?method=getpage");%><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core_rt" %>
MySQL实现分页的web小项目
以下是一个分页展示
书名
作者
单价
${book.name }
${book.author }
${book.price }
共${bookpage.totalpagenumber }页
当前第${bookpage.pageno }页
首页
上一页
下一页
末页
转到页