JavaWeb---数据分页

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数据分页

这个东西就像是百度最下端的那个东西一样的功能的，如下：

功能说明：

1、在不使用上方搜索功能时，能够查看到所有的数据

2、下面的分页功能将数据分成了许多页，下方的分页我规定只让他显示十页(总共不止十页，后面的要所在页面移动才能够显示出其他的页面，就像百度的分页功能一样的)，每一页只显示十行数据

3、上面的查询功能也是借用了数据库的模糊查询功能实现的

当然了，这个小项目还需要使用到三个jar包：c3p0-0.9.1.2.jar、commons-dbutils-1.4.jar、mysql-connector-java-5.1.5-bin.jar

下面是代码：

配置文件：c3p0-config.xml

<c3p0-config><!-- 默认配置，如果没有指定则使用这个配置 --><default-config><property name="driverClass">com.mysql.jdbc.Driver</property><property name="jdbcUrl"><![CDATA[jdbc:mysql://127.0.0.1:3306/mydata?useUnicode=true&characterEncoding=UTF-8]]></property><property name="user">root</property><property name="password"></property><!-- 初始化池大小 --><property name="initialPoolSize">2</property><!-- 最大空闲时间 --><property name="maxIdleTime">30</property><!-- 最多有多少个连接 --><property name="maxPoolSize">10</property><!-- 最少几个连接 --><property name="minPoolSize">2</property><!-- 每次最多可以执行多少个批处理语句 --><property name="maxStatements">50</property></default-config> <!-- 命名的配置 --><named-config name="hncu"><property name="driverClass">com.mysql.jdbc.Driver</property><property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/mydb</property><property name="user">root</property><property name="password"></property><property name="acquireIncrement">5</property><!-- 如果池中数据连接不够时一次增长多少个 --><property name="initialPoolSize">100</property><property name="minPoolSize">50</property><property name="maxPoolSize">1000</property><property name="maxStatements">0</property><property name="maxStatementsPerConnection">5</property> <!-- he's important, but there's only one of him --></named-config></c3p0-config>

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>PagesDivided</title>  </head>    <body>    <a href="<c:url value='PageServlet2'/>">数据分页的分页</a>  </body></html>

show2.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>showDividedPage</title>    <link rel="stylesheet" href="<c:url value='/css/table.css'/>"/>    <script type="text/javascript">    function change(obj){    window.location.href="<c:url value='/PageServlet2?page='/>"+obj.value;    }    </script>  </head>    <body>  <h3>数据查询</h3>  <form action='<c:url value="/PageServlet2"/>' method="post">  ID:<input type="text" name="id" value="${stud.id}"/>   Name:<input type="text" name="name" value="${stud.name}"/>   <input type="submit" value="模糊查询"/>  </form>  <hr/>    <h3 align="center">当前页面内容</h3>    <table>    <tr><th>学号</th><th>姓名</th></tr>    <c:forEach items="${result.datas}" var="map">    <tr>    <td>${map.id}</td>    <td>${map.name}</td>    </tr>    </c:forEach>    </table>    <br/><br/>    <c:if test="${1!=result.currentPage}">    <a href="<c:url value='/PageServlet2?page=${result.currentPage-1}'/>">上一页</a>    </c:if>   <c:forEach begin="${showStart}" end="${showEnd}" var="idx">   <c:if test="${idx==result.currentPage}">   ${idx}   </c:if>   <c:if test="${idx!=result.currentPage}">   <span id="unselectedPage">   <a href="<c:url value='/PageServlet2?page=${idx}'/>">${idx}</a>   </span>   </c:if>       </c:forEach>    <c:if test="${result.pageCount!=result.currentPage}">    <a href="<c:url value='/PageServlet2?page=${result.currentPage+1}'/>">下一页</a>    </c:if>        <select onchange="change(this)">    <c:forEach begin="1" end="${result.pageCount}" var="idx">    <option <c:if test="${idx==result.currentPage}">selected</c:if> value="${idx}">    第${idx}页    </option>    </c:forEach>    </select>  </body></html>

table.css

table{clear:left;border: 1px solid blue;width:500px;border-collapse: collapse;margin: auto;}td{border: 1px solid blue;text-align: center;}th{border: 1px solid blue;}body{text-align: center;}a{text-decoration: none;}#unselectedPage{border: 1px solid blue;width:500px;margin: auto;}

公共类C3p0Pool.java

package cn.hncu.pubs;import java.sql.Connection;import java.sql.SQLException;import javax.sql.DataSource;import com.mchange.v2.c3p0.ComboPooledDataSource;//我们的这个包装，只是为了把c3p0池做成让每个线程(客户端)获得的是同一个连接，方便做b/s框架下的事务public class C3p0Pool {private static DataSource pool;private static ThreadLocal<Connection> t=new ThreadLocal<Connection>();static {pool=new ComboPooledDataSource();}public static DataSource getDataSource(){return pool;}public static Connection getConnection() throws SQLException{Connection con=t.get();if (con==null){con=pool.getConnection();t.set(con);}return con;}}

DAO层

接口：IPageDAO2.java

package cn.hncu.page2.dao;import java.util.Map;import cn.hncu.page2.domain.Stud;public interface IPageDAO2 {public Map<String, Object> query(Integer pageNo, Stud stud) throws Exception;}

实现类：PageJdbc2.java

package cn.hncu.page2.dao;import java.util.HashMap;import java.util.List;import java.util.Map;import org.apache.commons.dbutils.QueryRunner;import org.apache.commons.dbutils.handlers.MapListHandler;import org.apache.commons.dbutils.handlers.ScalarHandler;import cn.hncu.page2.domain.Stud;import cn.hncu.pubs.C3p0Pool;public class PageJdbc2 implements IPageDAO2 {private final int pageSize=10;@Overridepublic Map<String, Object> query(Integer pageNo, Stud stud) throws Exception {Map<String, Object> result=new HashMap<String, Object>();//总行数String sql="select count(1) from dbutilsstud where 1=1 ";//查总行数String sql2="select * from dbutilsstud where 1=1 ";//查内容if (stud.getId()!=null&&stud.getId().trim().length()!=0){sql+="and id like '%"+stud.getId()+"%'";sql2+="and id like '%"+stud.getId()+"%'";}if (stud.getName()!=null&&stud.getName().trim().length()!=0){sql+="and name like '%"+stud.getName()+"%'";sql2+="and name like '%"+stud.getName()+"%'";}QueryRunner run=new QueryRunner(C3p0Pool.getDataSource());int rows=Integer.parseInt(""+run.query(sql, new ScalarHandler()));//总页数int pageCount=rows/pageSize + (rows%pageSize==0 ? 0:1);result.put("pageCount", pageCount);//分页面内容int startNo=(pageNo-1)*pageSize;sql2=sql2+" limit "+startNo+", "+pageSize;List<Map<String, Object>> datas=run.query(sql2, new MapListHandler());result.put("datas", datas);return result;}}

service层

接口：IPageService2.java

package cn.hncu.page2.service;import java.util.Map;import cn.hncu.page2.domain.Stud;public interface IPageService2 {public Map<String, Object> query(Integer pageNo, Stud stud) throws Exception;}

实现类：PageServiceImpl2.java

package cn.hncu.page2.service;import java.util.Map;import cn.hncu.page2.dao.IPageDAO2;import cn.hncu.page2.dao.PageJdbc2;import cn.hncu.page2.domain.Stud;public class PageServiceImpl2 implements IPageService2 {//注入daoIPageDAO2 dao=new PageJdbc2();@Overridepublic Map<String, Object> query(Integer pageNo, Stud stud) throws Exception {return dao.query(pageNo, stud);}}

servlet ：PageServlet2.java

package cn.hncu.page2.servlet;import java.io.IOException;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.hncu.page2.domain.Stud;import cn.hncu.page2.service.IPageService2;import cn.hncu.page2.service.PageServiceImpl2;public class PageServlet2 extends HttpServlet {//注入serviceIPageService2 service=new PageServiceImpl2();public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String pageNo=request.getParameter("page");if (pageNo==null||pageNo.trim().length()==0){pageNo="1";}Stud stud=null;if (request.getMethod().equalsIgnoreCase("GET")){stud=(Stud) request.getSession().getAttribute("stud");if (stud==null){stud=new Stud();}} else {stud=new Stud();String id=request.getParameter("id");String name=request.getParameter("name");stud.setId(id);stud.setName(name);request.getSession().setAttribute("stud", stud);}try {Integer iPageNo=Integer.parseInt(pageNo);Map<String, Object> result=service.query(iPageNo,stud);//给结果集补一个数据: currentPageresult.put("currentPage", iPageNo);//把结果集放入容器中request.setAttribute("result", result);int showSize=10;int showStart=0;int showEnd=0;int pageCount=Integer.parseInt(""+result.get("pageCount"));if (pageCount<showSize){showStart=1;showEnd=pageCount;} else {if (iPageNo<=(showSize/2+(showSize%2==0?0:1))){showStart=1;showEnd=showSize;} else {showStart=iPageNo-showSize/2;showEnd=showStart+showSize-1;}if (showEnd>pageCount){showEnd=pageCount;showStart=showEnd-showSize+1;}}request.setAttribute("showStart", showStart);request.setAttribute("showEnd", showEnd);//转到结果页面request.getRequestDispatcher("/jsps/show2.jsp").forward(request, response);} catch (NumberFormatException e) {throw new RuntimeException("当前页格式转换错误", e);} catch (Exception e) {e.printStackTrace();}}}

值对象层：Stud.java

package cn.hncu.page2.domain;public class Stud {private String id;private String name;public Stud() {}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic int hashCode() {final int prime = 31;int result = 1;result = prime * result + ((id == null) ? 0 : id.hashCode());return result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;Stud other = (Stud) obj;if (id == null) {if (other.id != null)return false;} else if (!id.equals(other.id))return false;return true;}}

具体的分包图像如下：

这个小项目我是放在了page2这个包里面的，page1是这个项目的另一个版本，就没贴上来了；另外下面的show.jsp也是给另一个用的，这个项目使用的是show2.jsp

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