struts2的自定义分页标签（原创）

1.写分页标签的相关支持类

package com.lowca.activity.expand.struts;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.components.UIBean;

import com.opensymphony.xwork2.util.ValueStack;

public class Pagebar extends UIBean {

	protected String totalRecord;
	protected String totalPage;
	protected String pageNo;
	protected String url;
	protected String style;

	public String getTotalRecord() {
		return totalRecord;
	}

	public void setTotalRecord(String totalRecord) {
		this.totalRecord = totalRecord;
	}

	public String getTotalPage() {
		return totalPage;
	}

	public void setTotalPage(String totalPage) {
		this.totalPage = totalPage;
	}

	public String getPageNo() {
		return pageNo;
	}

	public void setPageNo(String pageNo) {
		this.pageNo = pageNo;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public String getStyle() {
		return style;
	}

	public void setStyle(String style) {
		this.style = style;
	}

	public Pagebar(ValueStack stack, HttpServletRequest request,
			HttpServletResponse response) {
		super(stack, request, response);
	}

	@Override
	protected String getDefaultTemplate() {
		return "pagebar_" + style.toLowerCase();
	}

	@Override
	protected void evaluateExtraParams() {
		super.evaluateExtraParams();
		addParameter("totalRecord", findString(totalRecord));
		addParameter("totalPage", findString(totalPage));
		addParameter("pageNo", findString(pageNo));
		addParameter("url", findString(url));
		addParameter("style", style);
	}

}

package com.lowca.activity.expand.struts;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.components.Component;
import org.apache.struts2.components.UIBean;
import org.apache.struts2.views.jsp.ui.AbstractUITag;

import com.opensymphony.xwork2.util.ValueStack;

public class PagebarTag extends AbstractUITag {

	private static final long serialVersionUID = 1L;
	protected String totalRecord;
	protected String totalPage;
	protected String pageNo;
	protected String url;
	protected String style = "basic";

	@Override
	public Component getBean(ValueStack stack, HttpServletRequest request,
			HttpServletResponse response) {
		return new Pagebar(stack, request, response);
	}

	protected void populateParams() {
		super.populateParams();
		Pagebar pagebar = (Pagebar) component;
		pagebar.setTotalRecord(totalRecord);
		pagebar.setTotalPage(totalPage);
		pagebar.setPageNo(pageNo);
		pagebar.setUrl(url);
		pagebar.setStyle(style);
	}

	public String getTotalRecord() {
		return totalRecord;
	}

	public void setTotalRecord(String totalRecord) {
		this.totalRecord = totalRecord;
	}

	public String getTotalPage() {
		return totalPage;
	}

	public void setTotalPage(String totalPage) {
		this.totalPage = totalPage;
	}

	public String getPageNo() {
		return pageNo;
	}

	public void setPageNo(String pageNo) {
		this.pageNo = pageNo;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public String getStyle() {
		return style;
	}

	public void setStyle(String style) {
		this.style = style;
	}

}

2.写分页标签模板，模板放在src目录下d的“template/主题名”文件夹中。
因为我选择的struts2主题是simple，所以我把模板放在“template/simple”文件夹下面。
模板文件名是“pagebar_basic.ftl”.

<#-- 定义顶层变量并转换 -->
<#assign totalPage=parameters.totalPage?number />
<#assign totalRecord=parameters.totalRecord?number />
<#assign pageNo=parameters.pageNo?number />
<#assign url=parameters.url />
<#-- 模板逻辑 -->
<#if (totalRecord>0) && (totalPage>1) && (pageNo>0) && (pageNo<=totalPage)>
	<#--计算开始位置和结束位置-->
	<#if (pageNo<=5)>
		<#assign leftNo=1 />   
		<#if (totalPage<10)>
			<#assign rightNo=totalPage />
		<#else>
			<#assign rightNo=10 />
		</#if>
	<#elseif (pageNo>5) && (pageNo<=totalPage-5)>
		<#if (pageNo-4>0)>
			<#assign leftNo=pageNo-4 />
		<#else>
			<#assign leftNo=1 />
		</#if>
		<#if (pageNo+5<=totalPage)>
			<#assign rightNo=pageNo+5 />
		<#else>
			<#assign rightNo=totalPage />
		</#if>
	<#else>
		<#if (totalPage-10+1>0)>
			<#assign leftNo=totalPage-10+1 />
		<#else>
			<#assign leftNo=1 />
		</#if>
		<#assign rightNo=totalPage />
	</#if>
	<#--输出内容-->
	<div class="pagebar_warpper">
		<ul class="pagebar_ul">
			<li>共有<span class="pagebar_rc">${totalRecord?c}</span>条数据</li>
			<li class="pagebar_li">
				<a href="<@getURL text=url page=1 />">首页</a>
				<#if (pageNo-1>=1)>
					<a href="<@getURL text=url page=pageNo-1 />">上一页</a>
				</#if>
				<#list leftNo..rightNo as p>   
        			<#if (p==pageNo)>   
            			<span class="pagebar_curr">${p}</span>  
        			<#else>   
            			<a href="<@getURL text=url page=p />">${p}</a>
        			</#if>
    			</#list> 
    			<#if (pageNo+1<=totalPage)>
				<a href="<@getURL text=url page=pageNo+1 />">下一页</a>
				</#if>
				<a href="<@getURL text=url page=totalPage />">尾页</a>
			</li>
		</ul>
	</div>
</#if>

<#--产生动态URL的宏-->
<#macro getURL text page>   
    <#if (text?index_of("?")>0)>   
        <#lt/>${text?replace("?","?pageNo="+page)}<#rt/>
    <#else>   
        <#lt/>${text}?pageNo=${page}<#rt/>
    </#if>      
</#macro>

3.在WEB-INFO目录下新建一个tld文件，名字叫lowca-struts.tld,tld文件内容如下

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
	<tlib-version>1.0</tlib-version>
	<jsp-version>1.2</jsp-version>
	<short-name>l</short-name>
	<uri>/lowca-tags</uri>
	<display-name>自定义的struts标签</display-name>
	
	<tag>
		<name>pagebar</name>
		<tag-class>com.lowca.activity.expand.struts.PagebarTag</tag-class>
		<body-content>jsp</body-content>
		<description>分页工具条</description>
		<attribute>
			<name>totalRecord</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
			<type>int</type>
			<description>记录数</description>
		</attribute>		
		<attribute>
			<name>totalPage</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
			<type>int</type>
			<description>总页数</description>
		</attribute>		
		<attribute>
			<name>pageNo</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
			<type>int</type>
			<description>页码</description>
		</attribute>		
		<attribute>
			<name>url</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
			<type>java.lang.String</type>
			<description>url地址</description>
		</attribute>		
		<attribute>
			<name>style</name>
			<required>false</required>
			<rtexprvalue>true</rtexprvalue>
			<type>java.lang.String</type>
			<description>呈现样式</description>
		</attribute>
	</tag>
</taglib>

4.在web.xml注册这个自定义tld

	<!-- 注册自定义的标签 -->
	<jsp-config>
		<taglib>
			<taglib-uri>/lowca-tags</taglib-uri>
			<taglib-location>/WEB-INF/lowca-struts.tld</taglib-location>
		</taglib>
	</jsp-config>

5.在页面上面使用这个自定义标签

<%@ page language="java" pageEncoding="UTF-8"%>
<%@ taglib prefix="l" uri="/lowca-tags"%>

<s:debug></s:debug>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>测试</title>
  </head>
  
  <body>
    <l:pagebar pageNo="%{#parameters.pageNo}" url="test.jsp" totalPage="684" totalRecord="20498" style="basic" />
  </body>
</html>

至此，大功告成。

style是可以省略的属性，如果省略，则style默认值为basic。

给标签属性设置值的办法是%{ognl表达式}，例如：%{#parameters.pageNo}。
pageNo当前页码，totalPage总页数，totalRecord总记录数，这些属性都必须设置成动态查询出来的，比如：%{totalPage}，%{totalRecord}，%{#parameters.pageNo}

你可以定义你自己的模板来扩展这个标签，模板命名规则为pagebar_${style名称}.ftl，例如：pagebar_advance.ftl。