自定义分页标签详解
关于自定义分页标签的使用，我想大家都见过许多人写过，我今天也来凑个热闹写下我见到的自定义标签的使用步骤
既然是自定义标签那么肯定少不了类和tld文件这两大因素，因为这两个才能构成标签
首先奉献上最核心的自定义分页标签类的写法PagerTag.java,前提是要继承自TagSupport类
package com.javacrazyer.web.tag;
import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;
/**
* 分页标签处理类
*/
public class PagerTag extends TagSupport {
private static final long serialVersionUID = 5729832874890369508L;
private String url; //请求URI
private int pageSize = 10; //每页要显示的记录数
private int pageNo = 1; //当前页号
private int recordCount; //总记录数
@SuppressWarnings("unchecked")
public int doStartTag() throws JspException {
int pageCount = (recordCount + pageSize - 1) / pageSize; //计算总页数
//拼写要输出到页面的HTML文本
StringBuilder sb = new StringBuilder();
sb.append("<style type=\"text/css\">");
sb.append(".pagination {padding: 5px;float:right;font-size:12px;}");
sb.append(".pagination a, .pagination a:link, .pagination a:visited {padding:2px 5px;margin:2px;border:1px solid #aaaadd;text-decoration:none;color:#006699;}");
sb.append(".pagination a:hover, .pagination a:active {border: 1px solid #ff0000;color: #000;text-decoration: none;}");
sb.append(".pagination span.current {padding: 2px 5px;margin: 2px;border: 1px solid #ff0000;font-weight: bold;background-color: #ff0000;color: #FFF;}");
sb.append(".pagination span.disabled {padding: 2px 5px;margin: 2px;border: 1px solid #eee; color: #ddd;}");
sb.append("</style>\r\n");
sb.append("<div class=\"pagination\">\r\n");
if(recordCount == 0){
sb.append("<strong>没有可显示的项目</strong>\r\n");
}else{
//页号越界处理
if(pageNo > pageCount){ pageNo = pageCount; }
if(pageNo < 1){ pageNo = 1; }
sb.append("<form method=\"post\" action=\"").append(this.url)
.append("\" name=\"qPagerForm\">\r\n");
//获取请求中的所有参数
HttpServletRequest request = (HttpServletRequest) pageContext
.getRequest();
Enumeration<String> enumeration = request.getParameterNames();
String name = null; //参数名
String value = null; //参数值
//把请求中的所有参数当作隐藏表单域
while (enumeration.hasMoreElements()) {
name = enumeration.nextElement();
value = request.getParameter(name);
// 去除页号
if (name.equals("pageNo")) {
if (null != value && !"".equals(value)) {
pageNo = Integer.parseInt(value);
}
continue;
}
sb.append("<input type=\"hidden\" name=\"")
.append(name)
.append("\" value=\"")
.append(value)
.append("\"/>\r\n");
}
// 把当前页号设置成请求参数
sb.append("<input type=\"hidden\" name=\"").append("pageNo")
.append("\" value=\"").append(pageNo).append("\"/>\r\n");
// 输出统计数据
sb.append(" 共<strong>").append(recordCount)
.append("</strong>项")
.append(",<strong>")
.append(pageCount)
.append("</strong>页: \r\n");
//上一页处理
if (pageNo == 1) {
sb.append("<span class=\"disabled\">« 上一页")
.append("</span>\r\n");
} else {
sb.append("<a href=\"javascript:turnOverPage(")
.append((pageNo - 1))
.append(")\">« 上一页</a>\r\n");
}
//如果前面页数过多,显示"..."
int start = 1;
if(this.pageNo > 4){
start = this.pageNo - 1;
sb.append("<a href=\"javascript:turnOverPage(1)\">1</a>\r\n");
sb.append("<a href=\"javascript:turnOverPage(2)\">2</a>\r\n");
sb.append("…\r\n");
}
//显示当前页附近的页
int end = this.pageNo + 1;
if(end > pageCount){
end = pageCount;
}
for(int i = start; i <= end; i++){
if(pageNo == i){ //当前页号不需要超链接
sb.append("<span class=\"current\">")
.append(i)
.append("</span>\r\n");
}else{
sb.append("<a href=\"javascript:turnOverPage(")
.append(i)
.append(")\">")
.append(i)
.append("</a>\r\n");
}
}
//如果后面页数过多,显示"..."
if(end < pageCount - 2){
sb.append("…\r\n");
}
if(end < pageCount - 1){
sb.append("<a href=\"javascript:turnOverPage(")
.append(pageCount - 1)
.append(")\">")
.append(pageCount - 1)
.append("</a>\r\n");
}
if(end < pageCount){
sb.append("<a href=\"javascript:turnOverPage(")
.append(pageCount)
.append(")\">")
.append(pageCount)
.append("</a>\r\n");
}
//下一页处理
if (pageNo == pageCount) {
sb.append("<span class=\"disabled\">下一页 »")
.append("</span>\r\n");
} else {
sb.append("<a href=\"javascript:turnOverPage(")
.append((pageNo + 1))
.append(")\">下一页 »</a>\r\n");
}
sb.append("</form>\r\n");
// 生成提交表单的JS
sb.append("<script language=\"javascript\">\r\n");
sb.append(" function turnOverPage(no){\r\n");
sb.append(" if(no>").append(pageCount).append("){");
sb.append(" no=").append(pageCount).append(";}\r\n");
sb.append(" if(no<1){no=1;}\r\n");
sb.append(" document.qPagerForm.pageNo.value=no;\r\n");
sb.append(" document.qPagerForm.submit();\r\n");
sb.append(" }\r\n");
sb.append("</script>\r\n");
}
sb.append("</div>\r\n");
//把生成的HTML输出到响应中
try {
pageContext.getOut().println(sb.toString());
} catch (IOException e) {
throw new JspException(e);
}
return SKIP_BODY; //本标签主体为空,所以直接跳过主体
}
public void setUrl(String url) {
this.url = url;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public void setPageNo(int pageNo) {
this.pageNo = pageNo;
}
public void setRecordCount(int recordCount) {
this.recordCount = recordCount;
}
}
WEB-INF/pager.tld的写法
<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd">
<tlib-version>0.9</tlib-version>
<!--标签头-->
<short-name>w</short-name>
<!--将来在页面用taglib引用时的uri属性,这部分的名字可以随便写，只要是符合HTTP网址形式的 -->
<uri>http://javacrazyer.iteye.com/tags/pager</uri>
<!-- 自定义标签的描述信息 -->
<tag>
<!-- 标签名 -->
<name>pager</name>
<!-- 对应的标签处理类全限定名 -->
<tag-class>com.javacrazyer.web.tag.PagerTag</tag-class>
<!-- 标签主体的类型 -->
<body-content>empty</body-content>
<!-- 当前页号属性的描述信息 -->
<attribute>
<!-- 属性名 -->
<name>pageNo</name>
<!-- 该属性是否为必要的 -->
<required>true</required>
<!-- 属性值是否可以在JSP运行时期动态产生 -->
<rtexprvalue>true</rtexprvalue>
<!-- 属性的数据类型 -->
<type>int</type>
</attribute>
<!-- 总记录数属性的描述信息 -->
<attribute>
<name>recordCount</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
<type>int</type>
</attribute>
<!-- 总页数属性的描述信息 -->
<attribute>
<name>pageSize</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
<type>int</type>
</attribute>
<!-- 分页标签要跳转的URI属性的描述信息 -->
<attribute>
<name>url</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
<type>java.lang.String</type>
</attribute>
</tag>
</taglib>
好了，就上面的两个基本要素就已经构成了完整的分页标签，下面就差在页面的使用方式了
一般的使用步骤为在JSP页面中：
先倒入标签库：<%@taglib uri="http://javacrazyer.iteye.com/tags/pager" prefix="w"%>
然后使用： <w:pager pageSize="${pageSize}" pageNo="${pageNo}" url="do.jsp" recordCount="${pm.recordCount}"/>
具体使用示例，上面两个类保持不变
这个例子可以说非常好的纯servlet项目的例子，大家今后编程如果没有用到任何框架的话，我希望这个例子能给你带来点启示
前提是导入所有需要的jar包：包括common-dbcp.jar(数据源需要用到)，common-dbutils-1.2.jar(数据库CURD操作需要用到，可取代最原始的JDBC操作),junit.jar(测试用到)以及数据库驱动包
关于上面的common-dbutils非常有用，尤其是在非框架项目中，后面我提供下载
首先数据库，这个数据库脚本是我用navicat导出来的
/*
Navicat MySQL Data Transfer
Source Host : localhost:3306
Source Database : jstl
Target Host : localhost:3306
Target Database : jstl
Date: 2010-11-18 14:30:30
*/
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for news
-- ----------------------------
DROP TABLE IF EXISTS `news`;
CREATE TABLE `news` (
`detail` varchar(255) DEFAULT NULL,
`name` varchar(255) DEFAULT NULL,
`id` int(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1253 DEFAULT CHARSET=utf8;
实体类News.java
package com.javacrazyer.domain;
public class News {
private int id;
private String name;
private String detail;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDetail() {
return detail;
}
public void setDetail(String detail) {
this.detail = detail;
}
@Override
public String toString() {
return "News [detail=" + detail + ", id=" + id + ", name=" + name + "]";
}
}
NewsDao.java
package com.javacrazyer.dao;
import com.javacrazyer.common.PageModel;
import com.javacrazyer.domain.News;
public interface NewsDao {
PageModel<News> findByPager(int pageNo, int pageSize);
void createNews(News news);
void update(News news);
void delete(int id);
News findbyId(int id);
int findTotalSize();
}
NewsImplDao.java
package com.javacrazyer.daoimpl;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import com.javacrazyer.common.ConnectionFactory;
import com.javacrazyer.common.DAOException;
import com.javacrazyer.common.PageModel;
import com.javacrazyer.dao.NewsDao;
import com.javacrazyer.domain.News;
public class NewsDaoImpl implements NewsDao {
private QueryRunner qr = new QueryRunner();
public void createNews(News news) {
Connection conn = null;
String sql = "insert into news(name,detail) "
+ " values(?,?)";
Object[] param = { news.getName(),news.getDetail() };
try {
conn = ConnectionFactory.getConn();
qr.update(conn, sql, param);
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException("新增新闻信息时出现异常", e);
} finally {
DbUtils.closeQuietly(conn);
}
}
public PageModel<News> findByPager(int pageNo, int pageSize) {
PageModel<News> pm=new PageModel<News>();
Connection conn=null;
String sql="select *from news limit ?,?";
Object[] param={(pageNo-1)*pageSize,pageSize};
List<News> cates=null;
int count;
try {
conn=ConnectionFactory.getConn();
cates=(List<News>)qr.query(conn, sql, new BeanListHandler(News.class), param);
pm.setDatas(cates);
pm.setRecordCount(findTotalSize());
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException("分页查询出错",e);
}finally{
DbUtils.closeQuietly(conn);
}
return pm;
}
public void delete(int id) {
Connection conn = null;
String sql = "delete from news where id=?";
Object[] param = { id };
try {
conn = ConnectionFactory.getConn();
qr.update(conn, sql, param);
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException("删除新闻信息时出现异常", e);
} finally {
DbUtils.closeQuietly(conn);
}
}
public News findbyId(int id) {
News news=null;
Connection conn=null;
String sql="select * from news where id=?";
Object[] param={id};
try {
conn=ConnectionFactory.getConn();
news=(News)qr.query(conn,sql, new BeanHandler(News.class), param);
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException("根据ID查询新闻信息时出现异常",e);
}finally{
DbUtils.closeQuietly(conn);
}
return news;
}
public void update(News news) {
Connection conn=null;
String sql="update news set name=?,detail=? where id=?";
Object[] param={news.getName(),news.getDetail(),news.getId()};
try {
conn=ConnectionFactory.getConn();
qr.update(conn, sql, param);
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException("更新新闻信息出错",e);
}finally{
DbUtils.closeQuietly(conn);
}
}
public int findTotalSize() {
Connection conn=null;
String sql="select count(id) from news";
int count=0;
try {
conn=ConnectionFactory.getConn();
count=((Long)qr.query(conn,sql,new ScalarHandler())).intValue();
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException("查询记录总数出错",e);
}finally{
DbUtils.closeQuietly(conn);
}
return count;
}
}
PageModel.java
package com.javacrazyer.common;
import java.util.List;
/**
* 分页组件(包含当前页结果数据列表和总记录数)
* 注意，它不是持久化实体类
*
*/
public class PageModel<T> {
private int recordCount;
private List<T> datas;
public int getRecordCount() {
return recordCount;
}
public void setRecordCount(int recordCount) {
this.recordCount = recordCount;
}
public List<T> getDatas() {
return datas;
}
public void setDatas(List<T> datas) {
this.datas = datas;
}
}
数据库连接工具类
package com.javacrazyer.common;
import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
import javax.sql.DataSource;
import org.apache.commons.dbcp.BasicDataSource;
/**
*
* 数据库连接工厂类
*
*/
public class ConnectionFactory {
private static DataSource dss=null;
static{
Properties pr=new Properties();
try {
pr.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("config.properties"));
} catch (IOException e) {
e.printStackTrace();
}
BasicDataSource ds=new BasicDataSource();
ds.setDriverClassName(pr.getProperty("driver_name"));
ds.setUrl(pr.getProperty("url"));
ds.setUsername(pr.getProperty("username"));
ds.setPassword(pr.getProperty("password"));
dss=ds;
}
private ConnectionFactory(){}
public static Connection getConn() throws SQLException{
return dss.getConnection();
}
}
上面代码用到的config.properties
#mysql
driver_name=com.mysql.jdbc.Driver
url=jdbc:mysql:///jstl
username=root
password=root
DAO实例工具类，类似于Spring的BeanFactory
package com.javacrazyer.common;
import java.io.IOException;
import java.util.Properties;
/**
*
*
* 自定义简单工厂
*/
public class DAOFactory {
public static Properties pr = new Properties();
static {
try {
pr.load(Thread.currentThread().getContextClassLoader()
.getResourceAsStream("daoname.properties"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static Object newInstance(String name){
Object obj=null;
String daoImplName = pr.getProperty(name);
if(null!=daoImplName){
try {
obj=Class.forName(daoImplName).newInstance();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{
throw new RuntimeException("指定名称的DAO类未找到");
}
return obj;
}
}
上面代码用到的配置daoname.properties
newsdao=com.javacrazyer.daoimpl.NewsDaoImpl
coursedao=com.javacrazyer.web.tag.CourseDAOImpl
teacherdao=com.javacrazyer.web.tag.TeacherDAOImpl
catedao=com.javacrazyer.web.tag.CategoryDAOImpl
gradao=com.javacrazyer.web.tag.GraduateDAOImpl
accountdao=com.javacrazyer.web.tag.AccountDAOImpl
平时开发中常用到的常量存放类
package com.javacrazyer.common;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* 系统常量类
*
* @author tjitcast.com
*/
public class Constant {
/** 状态：可用 */
public static final int STATUS_ACTIVE = 1;
/** 状态：不可用 */
public static final int STATUS_INACTIVE = 0;
/** 课程类型：全日制 */
public static final int COURSE_FULL_TIME = 1;
/** 课程类型：业务 */
public static final int COURSE_SPARE_TIME = 2;
/** 课程类型：免费 */
public static final int COURSE_FREE_TIME = 3;
/** 账号类型：超级管理员 */
public static final int ACCOUNT_SUPER = 100;
/** 账号类型：普通管理员 */
public static final int ACCOUNT_COMMON = 50;
/** 账号状态：激活 */
public static final int ACCOUNT_STATUS_ACTIVE = 1;
/** 账号状态：未激活 */
public static final int ACCOUNT_STATUS_INACTIVE = 0;
/** 账号状态：锁定 */
public static final int ACCOUNT_STATUS_LOCK = -1;
/** 每页要显示的记录数：10 */
public static final int PAGE_SIZE =10;
private static Map<Integer, String> statusMap = new LinkedHashMap<Integer, String>();
static {
// 对状态Map进行初始化
statusMap.put(Integer.valueOf(STATUS_ACTIVE), "可用");
statusMap.put(Integer.valueOf(STATUS_INACTIVE), "不可用");
}
public static Map<Integer, String> getStatusMap() {
return statusMap;
}
}
开发中常用到的用来判断空值，类型转换，集合操作等等的自定义常用工具类
/**
* ClassName: DataValidateUtil.java
* created on Jul 10, 2009
* Copyrights 2009 www.tjicast.com All rights reserved.
* site: http://www.tjitcast.com
* email: [email protected]
* phone: 022-83726777,89721888
*/
package com.javacrazyer.common;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.Map;
/**
* 对一些常用数据进行操作的工具类
*
*/
public class DataOptUtil {
/** 日期长格式 */
public static final String DATE_PATTERN_LONG = "yyyy-MM-dd HH:mm:ss";
/** 日期格式 */
public static final String DATE_PATTERN = "yyyy-MM-dd";
public static boolean isNotNull(String str){
if(null != str && !"".equals(str)){
return true;
}else{
return false;
}
}
public static int parseInt(String str){
if(isNotNull(str)){
return Integer.parseInt(str);
}else{
throw new RuntimeException("字符串为空，不能转换成数字");
}
}
public static Date parseDate(String str, String pattern){
SimpleDateFormat sdf = new SimpleDateFormat(pattern);
Date date = null;
if(isNotNull(str)){
try {
date = sdf.parse(str);
} catch (ParseException e) {
e.printStackTrace();
}
}else{
throw new RuntimeException("字符串为空，不能转换成日期");
}
return date;
}
public static Date parseDate(String str){
return parseDate(str, DataOptUtil.DATE_PATTERN);
}
public static Date parseLongDate(String str){
return parseDate(str, DataOptUtil.DATE_PATTERN_LONG);
}
public static String date2String(Date date, String pattern){
SimpleDateFormat sdf = new SimpleDateFormat(pattern);
return sdf.format(date);
}
public static String Date2String(Date date){
return date2String(date, DataOptUtil.DATE_PATTERN);
}
public static String Date2LongString(Date date){
return date2String(date, DataOptUtil.DATE_PATTERN_LONG);
}
public static int getSize(Collection<?> coll){
int size = coll == null ? 0 : coll.size();
return size;
}
public static int getSize(Map<?,?> map){
int size = map == null ? 0 : map.size();
return size;
}
public static int getLength(Object[] obj){
int length = 0;
length = obj == null ? 0 : obj.length;
return length;
}
}
还有一个自定义非受检异常类
package com.javacrazyer.common;
/**
*
* 自定义的非受检异常
*
*/
public class DAOException extends RuntimeException {
private static final long serialVersionUID = 1047748781772098415L;
public DAOException() {
super();
}
public DAOException(String message, Throwable cause) {
super(message, cause);
}
public DAOException(String message) {
super(message);
}
public DAOException(Throwable cause) {
super(cause);
}
}
页面方面
index.html
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta http-equiv="refresh" content="0; url=do.jsp" />
</head>
</html>
do.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@page import="com.javacrazyer.common.DAOFactory"%>
<%@page import="com.javacrazyer.dao.NewsDao"%>
<%@page import="com.javacrazyer.common.PageModel"%>
<%@page import="com.javacrazyer.common.DataOptUtil"%>
<%@page import="com.javacrazyer.common.Constant"%>
<%@page import="com.javacrazyer.domain.News"%>
<%
NewsDao dao=(NewsDao)DAOFactory.newInstance("newsdao");
int pageNo = 1;
String temp = request.getParameter("pageNo");
if (DataOptUtil.isNotNull(temp)) {
pageNo = Integer.parseInt(temp);
}
int categoryid = 1;
String temp1 = request.getParameter("category_id");
if (DataOptUtil.isNotNull(temp1)) {
categoryid = Integer.parseInt(temp1);
}
PageModel<News> pm=dao.findByPager(pageNo,Constant.PAGE_SIZE);
request.setAttribute("pm",pm);
request.setAttribute("pageNo", Integer.valueOf(pageNo));
request.setAttribute("pageSize", Constant.PAGE_SIZE);
request.getRequestDispatcher("/index.jsp").forward(request,response);
%>
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="http://javacrazyer.iteye.com/tags/pager" prefix="w"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<h3>新闻列表</h3><hr/>
<table>
<tr><td>新闻编号</td><td>新闻标题</td><td>新闻内容</td></tr>
<c:forEach items="${pm.datas}" var="news">
<tr><td>${news.id}</td><td>${news.name }</td><td>${news.detail}</td></tr>
</c:forEach>
</table>
<w:pager pageSize="${pageSize}" pageNo="${pageNo}" url="do.jsp" recordCount="${pm.recordCount}"/>
</body>
</html>
实际运行出来的效果
虽然自定义标签使用成功了，但总不可能每次开发项目都写下这个类和加上TLD文件吧，比较简洁的方式就是将编译类编译好的class文件和tld一起打成jar包，以后直接导入到项目lib中就可以使用了
具体步骤：将整个目录com/javacrazyer/web/tag/PagerTag.class放到一个目录中去，同时将META-INF拷贝到与com目录相同的目录下，最后将WEB-INF下的pager.tld拷贝到MET-INF下
META-INF中的文件
最后将com文件夹与META-INF文件选中右键添加到压缩文件，选中ZIP压缩格式
改名为jar后缀后确定，这样在同一目录就会多出一个jar来了
以后只要在需要的地方导入该分页JAR包，并且在网页上
<%@taglib uri="http://javacrazyer.iteye.com/tags/pager" prefix="w"%>
<w:pager pageSize="${pageSize}" pageNo="${pageNo}" url="do.jsp"