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

<span style="font-size: medium;">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("&nbsp;共<strong>").append(recordCount)
                .append("</strong>项")
                .append(",<strong>")
                .append(pageCount)
                .append("</strong>页:&nbsp;\r\n");

            //上一页处理
            if (pageNo == 1) {
                sb.append("<span class=\"disabled\">&laquo;&nbsp;上一页")
                    .append("</span>\r\n");
            } else {
                sb.append("<a href=\"javascript:turnOverPage(")
                  .append((pageNo - 1))
                  .append(")\">&laquo;&nbsp;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("&hellip;\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("&hellip;\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&nbsp;&raquo;")
                    .append("</span>\r\n");
            } else {
                sb.append("<a href=\"javascript:turnOverPage(")
                    .append((pageNo + 1))
                    .append(")\">下一页&nbsp;&raquo;</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;
    }
}</span>

 WEB-INF/pager.tld的写法

<span style="font-size: medium;"><?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></span>

 

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

<span style="font-size: medium;">/*
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;
</span>

 

实体类News.java

<span style="font-size: medium;">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 + "]";
    }


}</span>

 NewsDao.java

<span style="font-size: medium;">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();


}</span>

NewsImplDao.java

<span style="font-size: medium;">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;
    }

}</span>

 PageModel.java

<span style="font-size: medium;">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;
    }
}  </span>

 

 数据库连接工具类

<span style="font-size: medium;">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();
    }

}</span>

  上面代码用到的config.properties

<span style="font-size: medium;">#mysql
driver_name=com.mysql.jdbc.Driver
url=jdbc:mysql:///jstl
username=root
password=root</span>

DAO实例工具类，类似于Spring的BeanFactory

<span style="font-size: medium;">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;
    }
}</span>

  上面代码用到的配置daoname.properties

<span style="font-size: medium;">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</span>

 平时开发中常用到的常量存放类

<span style="font-size: medium;">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;
    }

}</span>

 

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

<span style="font-size: medium;">/**
 *  ClassName: DataValidateUtil.java
 *  created on Jul 10, 2009
 *  Copyrights 2009 www.tjicast.com All rights reserved.
 *  site: http://www.tjitcast.com
 *  email: [e-mail]
 *  phone: [phone]
 */
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;
    }
}</span>

 

还有一个自定义非受检异常类

<span style="font-size: medium;">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);
    }

}
</span>

 

页面方面

index.html

<span style="font-size: medium;"><html>
    <head>
         <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
        <meta http-equiv="refresh" content="0; url=do.jsp" />
    </head>
</html></span>

 

do.jsp

<span style="font-size: medium;"><%@ 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);
%></span>

 index.jsp

<span style="font-size: medium;"><%@ 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></span>

 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"