jsp实现分页和页面跳转功能

      本文主要介绍在jsp中实现分页功能和页面跳转功能，能够实现数据的分页显示和跳转到指定页面的功能，具体效果如图

                       

由于该功能是一个书城项目的一部分，所以数据来源于该项目，具体数据库(数据库方面采用c3p0连接池，使用的是mysql数据库)文件可以在点击打开链接下载，整个项目可以在点击打开链接下载（不过由于使用的是MyeElipse2013,所以请使用此版本或者更高版本导入工程）。

下面具体介绍一下这个小功能

1. 这个项目的目录结构：

2.显示的数据主要是图书的相关信息因此Bean类是图书Book的相关信息即com.page.book.domain中Book类的相关信息如下

package com.page.book.domain;import org.apache.log4j.Category;public class Book {private String bid;//主键private String bname;//图名private String author;//作者private double price;//定价private double currPrice;//当前价private double discount;//折扣private String press;//出版社private String publishtime;//出版时间private int edition;//版次private int pageNum;//页数private int wordNum;//字数private String printtime;//刷新时间private int booksize;//开本private String paper;//纸质private Category category;//所属分类private String image_w;//大图路径private String image_b;//小图路径public String getBid() {return bid;}public void setBid(String bid) {this.bid = bid;}public String getBname() {return bname;}public void setBname(String bname) {this.bname = bname;}public String getAuthor() {return author;}public void setAuthor(String author) {this.author = author;}public double getPrice() {return price;}public void setPrice(double price) {this.price = price;}public double getCurrPrice() {return currPrice;}public void setCurrPrice(double currPrice) {this.currPrice = currPrice;}public double getDiscount() {return discount;}public void setDiscount(double discount) {this.discount = discount;}public String getPress() {return press;}public void setPress(String press) {this.press = press;}public String getPublishtime() {return publishtime;}public void setPublishtime(String publishtime) {this.publishtime = publishtime;}public int getEdition() {return edition;}public void setEdition(int edition) {this.edition = edition;}public int getPageNum() {return pageNum;}public void setPageNum(int pageNum) {this.pageNum = pageNum;}public int getWordNum() {return wordNum;}public void setWordNum(int wordNum) {this.wordNum = wordNum;}public String getPrinttime() {return printtime;}public void setPrinttime(String printtime) {this.printtime = printtime;}public int getBooksize() {return booksize;}public void setBooksize(int booksize) {this.booksize = booksize;}public String getPaper() {return paper;}public void setPaper(String paper) {this.paper = paper;}public Category getCategory() {return category;}public void setCategory(Category category) {this.category = category;}public String getImage_w() {return image_w;}public void setImage_w(String image_w) {this.image_w = image_w;}public String getImage_b() {return image_b;}public void setImage_b(String image_b) {this.image_b = image_b;}}

3.dao层的实现

package com.page.book.dao;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import org.apache.commons.dbutils.QueryRunner;import org.apache.commons.dbutils.handlers.BeanListHandler;import org.apache.commons.dbutils.handlers.ScalarHandler;import cn.itcast.jdbc.TxQueryRunner;import com.page.book.domain.Book;import com.page.pager.Expression;import com.page.pager.PageBean;import com.page.pager.PageConstants;public class BookDao {private QueryRunner qr = new TxQueryRunner();/** * 按分类查询 * @param cid * @param pc * @return * @throws SQLException  */public PageBean<Book> findByCategory(String cid, int pc) throws SQLException {List<Expression> exprList = new ArrayList<Expression>();exprList.add(new Expression("cid", "=", cid));return findByCriteria(exprList, pc);}/** * 通用的查询方法 * @param exprList * @param pc * @return * @throws SQLException  */private PageBean<Book> findByCriteria(List<Expression> exprList, int pc) throws SQLException {/* * 1. 得到ps * 2. 得到tr * 3. 得到beanList * 4. 创建PageBean，返回 *//* * 1. 得到ps */int ps = PageConstants.BOOK_PAGE_SIZE;//每页记录数/* * 2. 通过exprList来生成where子句 */StringBuilder whereSql = new StringBuilder(" where 1=1"); List<Object> params = new ArrayList<Object>();//SQL中有问号，它是对应问号的值for(Expression expr : exprList) {/* * 添加一个条件上， * 1) 以and开头 * 2) 条件的名称 * 3) 条件的运算符，可以是=、!=、>、< ... is null，is null没有值 * 4) 如果条件不是is null，再追加问号，然后再向params中添加一与问号对应的值 */whereSql.append(" and ").append(expr.getName()).append(" ").append(expr.getOperator()).append(" ");// where 1=1 and bid = ?if(!expr.getOperator().equals("is null")) {whereSql.append("?");params.add(expr.getValue());}}/* * 3. 总记录数  */String sql = "select count(*) from t_book" + whereSql;Number number = (Number)qr.query(sql, new ScalarHandler(), params.toArray());int tr = number.intValue();//得到了总记录数/* * 4. 得到beanList，即当前页记录 */sql = "select * from t_book" + whereSql + " order by orderBy limit ?,?";params.add((pc-1) * ps);//当前页首行记录的下标params.add(ps);//一共查询几行，就是每页记录数List<Book> beanList = qr.query(sql, new BeanListHandler<Book>(Book.class), params.toArray());/* * 5. 创建PageBean，设置参数 */PageBean<Book> pb = new PageBean<Book>();/* * 其中PageBean没有url，这个任务由Servlet完成 */pb.setBeanList(beanList);pb.setPc(pc);pb.setPs(ps);pb.setTr(tr);return pb;}}

4.service层的实现

package com.page.book.service;import java.sql.SQLException;import com.page.book.dao.BookDao;import com.page.book.domain.Book;import com.page.pager.PageBean;public class BookService {private BookDao bookDao = new BookDao();/** * 按分类查 * @param cid * @param pc * @return */public PageBean<Book> findByCategory(String cid, int pc) {try {return bookDao.findByCategory(cid, pc);} catch (SQLException e) {throw new RuntimeException(e);}}}

5.servlet的实现

package com.page.book.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.itcast.servlet.BaseServlet;import com.page.book.domain.Book;import com.page.book.service.BookService;import com.page.pager.PageBean;public class BookServlet extends BaseServlet {/** *  */private static final long serialVersionUID = 1L;private BookService bookService = new BookService();/** * 获取当前页码 * @param req * @return */private int getPc(HttpServletRequest req) {int pc = 1;String param = req.getParameter("pc");if(param != null && !param.trim().isEmpty()) {try {pc = Integer.parseInt(param);} catch(RuntimeException e) {}}return pc;}/** * 截取url，页面中的分页导航中需要使用它做为超链接的目标！ * @param req * @return *//* * http://localhost:8080/goods/BookServlet?methed=findByCategory&cid=xxx&pc=3 * /goods/BookServlet + methed=findByCategory&cid=xxx&pc=3 */private String getUrl(HttpServletRequest req) {String url = req.getRequestURI() + "?" + req.getQueryString();System.out.println("url:"+url);/* * 如果url中存在pc参数，截取掉，如果不存在那就不用截取。 */int index = url.lastIndexOf("&pc=");if(index != -1) {url = url.substring(0, index);}return url;}public String findByCategory(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {/* * 1. 得到pc：如果页面传递，使用页面的，如果没传，pc=1 */int pc = getPc(req);/* * 2. 得到url：... */String url = getUrl(req);System.out.println("url----"+url);/* * 3. 获取查询条件，本方法就是cid，即分类的id */String cid = req.getParameter("cid");/* * 4. 使用pc和cid调用service#findByCategory得到PageBean */PageBean<Book> pb = bookService.findByCategory(cid, pc);/* * 5. 给PageBean设置url，保存PageBean，转发到/jsps/book/list.jsp */pb.setUrl(url);req.setAttribute("pb", pb);return "f:/pager/pager.jsp";//f代表转发}}

6.关于分页的相关类的实现

package com.page.pager;public class PageConstants {public static final int BOOK_PAGE_SIZE = 12;//图书每页记录数}

7.pageBean的实现

package com.page.pager;import java.util.List;/** * 分页Bean，它会在各层之间传递 * * @param <T> */public class PageBean<T> {private int pc;//当前页码private int tr;//总记录数private int ps;//每页记录数private String url;//请求路径和参数，例如BookServlet?method=findXXX&cid=1&bname=2private List<T> beanList;// 计算总页数public int getTp() {int tp = tr / ps;return tr % ps == 0 ? tp : tp + 1;}public int getPc() {return pc;}public void setPc(int pc) {this.pc = pc;}public int getTr() {return tr;}public void setTr(int tr) {this.tr = tr;}public int getPs() {return ps;}public void setPs(int ps) {this.ps = ps;}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}public List<T> getBeanList() {return beanList;}public void setBeanList(List<T> beanList) {this.beanList = beanList;}}

8.数据库辅助类

package com.page.pager;public class Expression {private String name;private String operator;private String value;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getOperator() {return operator;}public void setOperator(String operator) {this.operator = operator;}public String getValue() {return value;}public void setValue(String value) {this.value = value;}@Overridepublic String toString() {return "Expression [name=" + name + ", operator=" + operator+ ", value=" + value + "]";}public Expression() {super();// TODO Auto-generated constructor stub}public Expression(String name, String operator, String value) {super();this.name = name;this.operator = operator;this.value = value;toString();}}

9.c3p0文件的配置

<?xml version="1.0" encoding="UTF-8" ?><c3p0-config><default-config> <property name="jdbcUrl"><![CDATA[jdbc:mysql://localhost:3306/goods?useUnicode=true&characterEncoding=UTF8&useServerPrepStmts=true&prepStmtCacheSqlLimit=256&cachePrepStmts=true&prepStmtCacheSize=256&rewriteBatchedStatements=true]]></property><property name="driverClass">com.mysql.jdbc.Driver</property><property name="user">root</property><property name="password">906363842aq</property><property name="acquireIncrement">3</property><property name="initialPoolSize">10</property><property name="minPoolSize">2</property><property name="maxPoolSize">10</property></default-config></c3p0-config>

10.分页前端的操作

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><link rel="stylesheet" type="text/css" href="<c:url value='/pager/pager.css'/>" /><script type="text/javascript" src="<c:url value='/pager/jquery-1.5.1.js'/>"></script><script type="text/javascript">function _go() {var pc = $("#pageCode").val();//获取文本框中的当前页码if(!/^[1-9]\d*$/.test(pc)) {//对当前页码进行整数校验alert('请输入正确的页码！');return;}if(pc > ${pb.tp}) {//判断当前页码是否大于最大页alert('请输入正确的页码！');return;}location = "${pb.url}&pc=" + pc;}</script><table border="1"> <tr>  <th>书名</th>  <th>书价</th>  <th>折扣</th>  <th>作者</th>  <th>出版社</th>  <th>出版时间</th>  </tr>  <c:forEach items="${pb.beanList }" var="book">   <tr>  <td>${book.bname }</td>    <td>${book.price }</td>    <td>${book.discount }折</td>    <td>${book.author }</td>    <td>${book.press }</td>    <td>${book.publishtime }</td>  </tr>  </c:forEach></table><div class="divBody">  <div class="divContent">    <%--上一页 --%><c:choose><c:when test="${pb.pc eq 1 }"><span class="spanBtnDisabled">上一页</span></c:when><c:otherwise><a href="${pb.url }&pc=${pb.pc-1}" class="aBtn bold">上一页</a></c:otherwise></c:choose>                <%--我们需要计算页码列表的开始和结束位置，即两个变量begin和end计算它们需要通过当前页码！1. 总页数不足6页--> begin=1, end=最大页2. 通过公式设置begin和end，begin=当前页-1，end=当前页+33. 如果begin<1，那么让begin=1，end=64. 如果end>tp, 让begin=tp-5, end=tp --%> <c:choose> <c:when test="${pb.tp <= 6 }"> <c:set var="begin" value="1"/> <c:set var="end" value="${pb.tp }"/> </c:when> <c:otherwise> <c:set var="begin" value="${pb.pc-2 }"/> <c:set var="end" value="${pb.pc + 3}"/> <c:if test="${begin < 1 }">   <c:set var="begin" value="1"/>   <c:set var="end" value="6"/> </c:if> <c:if test="${end > pb.tp }">   <c:set var="begin" value="${pb.tp-5 }"/>   <c:set var="end" value="${pb.tp }"/> </c:if>  </c:otherwise> </c:choose>  <c:forEach begin="${begin }" end="${end }" var="i">   <c:choose>     <c:when test="${i eq pb.pc }">       <span class="spanBtnSelect">${i }</span>     </c:when>     <c:otherwise>       <a href="${pb.url }&pc=${i}" class="aBtn">${i }</a>     </c:otherwise>   </c:choose>                      </c:forEach>    <%-- 计算begin和end --%>      <%-- 如果总页数<=6，那么显示所有页码，即begin=1 end=${pb.tp} --%>        <%-- 设置begin=当前页码-2，end=当前页码+3 --%>          <%-- 如果begin<1，那么让begin=1 end=6 --%>          <%-- 如果end>最大页，那么begin=最大页-5 end=最大页 --%>        <%-- 显示点点点 --%>    <c:if test="${end < pb.tp }">      <span class="spanApostrophe">...</span>    </c:if>          <%--下一页 --%><c:choose><c:when test="${pb.pc eq pb.tp }"><span class="spanBtnDisabled">下一页</span></c:when><c:otherwise><a href="${pb.url }&pc=${pb.pc+1}" class="aBtn bold">下一页</a></c:otherwise></c:choose>                                  <%-- 共N页 到M页 --%>    <span>共${pb.tp }页</span>    <span>到</span>    <input type="text" class="inputPageCode" id="pageCode" value="${pb.pc }"/>    <span>页</span>    <a href="javascript:_go();" class="aSubmit">确定</a>  </div></div>

到这里就实现了分页的功能和页面跳转的功能，如果有什么问题可以留言，谢谢！