jsp实现分页（限定显示指定页数）和页面跳转功能 |
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jsp实现分页（限定显示指定页数）和页面跳转功能
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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 [java] view plain copy print ? 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; } }
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
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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 findByCategory(String cid, int pc) throws SQLException { List exprList = new ArrayList(); 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 findByCriteria(List 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 params = new ArrayList();//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 beanList = qr.query(sql, new BeanListHandler(Book.class),
params.toArray());
/*
* 5. 创建PageBean，设置参数
*/
PageBean pb = new PageBean();
/*
* 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
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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 findByCategory(String cid, int pc) { try { return bookDao.findByCategory(cid, pc); } catch (SQLException e) { throw new RuntimeException(e); } } }
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 findByCategory(String cid, int pc) {
try {
return bookDao.findByCategory(cid, pc);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
5.servlet的实现
[java]
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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 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 } }
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 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
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package com.page.pager; public class PageConstants { public static final int BOOK_PAGE_SIZE = 12;//图书每页记录数 }
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
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package com.page.pager; import java.util.List; /** * 分页Bean，它会在各层之间传递 * * @param */ public class PageBean { 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 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 getBeanList() { return beanList; } public void setBeanList(List beanList) { this.beanList = beanList; } }
package com.page.pager;
import java.util.List;
/**
* 分页Bean，它会在各层之间传递
*
* @param
*/
public class PageBean {
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 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 getBeanList() {
return beanList;
}
public void setBeanList(List beanList) {
this.beanList = beanList;
}
}
8.数据库辅助类
[java]
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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(); } }
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
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jdbc:mysql://localhost:3306/goods?useUnicode=true&characterEncoding=UTF8&useServerPrepStmts=true&prepStmtCacheSqlLimit=256&cachePrepStmts=true&prepStmtCacheSize=256&rewriteBatchedStatements=true ]]> com.mysql.jdbc.Driver root 906363842aq 3 10 2 10
com.mysql.jdbc.Driver
root
906363842aq
3
10
2
10
10.分页前端的操作
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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; } 书名 书价 折扣 作者 出版社 出版时间 ${book.bname } ${book.price } ${book.discount }折 ${book.author } ${book.press } ${book.publishtime } 上一页 上一页 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begintp, 让begin=tp-5, end=tp --%> ${i } ${i }
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;
}
书名
书价
折扣
作者
出版社
出版时间
${book.bname }
${book.price }
${book.discount }折
${book.author }
${book.press }
${book.publishtime }
上一页
上一页
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begintp, 让begin=tp-5, end=tp
--%>
${i }
${i }
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