jsp实现分页和页面跳转功能

时间：2022-09-20 21:03:01

      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

                       jsp实现分页和页面跳转功能jsp实现分页和页面跳转功能

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：

jsp实现分页和页面跳转功能

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=2
	private 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;
	}
	@Override
	public 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+3
3. 如果begin<1，那么让begin=1，end=6
4. 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！

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