JSP自定义分页标签TAG

首先我们需要在WEB-INF/tld/目录下创建page.tld文件

<?xml version="1.0" encoding="ISO-8859-1"?>
<taglib>
	<tlib-version>1.0</tlib-version>
	<jsp-version>1.2</jsp-version>
	<short-name>page</short-name>
	<uri>http://www.kevin.com/taglibs/page</uri>
	<tag>
		<name>htmlPage</name>
		<tag-class>com.lss.common.tag.PageTag</tag-class>
		<body-content>JSP</body-content>
		<description>htmlPage Tag</description>
		<attribute>
			<name>pageNo</name>
			<required>false</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
		<attribute>
			<name>pageSize</name>
			<required>false</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
		<attribute>
			<name>totalSum</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
		<attribute>
			<name>url</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
		<attribute>
			<name>showPage</name>
			<required>false</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
	</tag>
</taglib>

package com.lss.common.tag;

import java.io.IOException;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import com.lss.common.page.HtmlPage;
import com.lss.common.page.Page;
import com.lss.common.page.VariablePage;

/**
 * 分页处理标签
 * 
 * @description
 * @DATE 2012-3-11下午09:08:46
 */
public class PageTag extends TagSupport {
	private int pageNo;
	private int pageSize = 10;
	private int totalSum;
	private int showPage = 10;
	private String url;

	public int getPageNo() {
		return pageNo;
	}

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

	public int getPageSize() {
		return pageSize;
	}

	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}

	public int getTotalSum() {
		return totalSum;
	}

	public void setTotalSum(int totalSum) {
		this.totalSum = totalSum;
	}

	public int getShowPage() {
		return showPage;
	}

	public void setShowPage(int showPage) {
		this.showPage = showPage;
	}

	public String getUrl() {
		return url;
	}

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

	@Override
	public int doEndTag() throws JspException {
		if (pageSize == 0) {
			return TagSupport.SKIP_PAGE;// 不显示分页
		} else if (pageSize > totalSum) {
			return TagSupport.SKIP_BODY;// 不显示分页
		}
		JspWriter out = pageContext.getOut();
		try {
			if (url.indexOf(";jsessionid=") == -1) {
				if (url.indexOf("?") == -1) {
					url += ";jsessionid=" + pageContext.getSession().getId() + "?pageNo=";
				} else {
					url = url.replaceFirst("\\?", ";jsessionid=" + pageContext.getSession().getId() + "?");
					if (url.indexOf("pageNo=") == -1) {
						url += "&pageNo=";
					}
				}
			}
			url = pageContext.getServletContext().getContextPath() + url;
			VariablePage variablePage = new VariablePage(pageNo, totalSum, pageSize, url);
			variablePage.setShowPageNum(showPage);
			Page page = new HtmlPage(variablePage);
			out.print(page.getFirstNo() + "  " + page.getBackpageNum() + "  " + page.pagination() + "  " + page.getNextpageNum() + "  " + page.getLastNo());
		} catch (IOException ex) {
			ex.printStackTrace();
		}
		return super.doEndTag();
	}

	@Override
	public void release() {
		url = null;
		pageNo = 0;
		totalSum = 0;
		pageSize = 10;
		super.release();
	}

	private static final long serialVersionUID = -2642907859641024483L;
}

/**
 * HTML 分页类
 * 
 * @description
 * @DATE 2012-3-11下午10:33:14
 */
public class HtmlPage extends Page {
	public HtmlPage(VariablePage variablePage) {
		super(variablePage);
	}

	public String pagination() {
		String printNo = "";
		// 如果已分页；并且页数小于等于要显示的页数
		if (variablePage.totalPage > 1 && variablePage.totalPage <= variablePage.showPageNum) {
			return displayAll();
			// 如果分页数：大于显示的页码数
		} else if (variablePage.totalPage > 1 && variablePage.totalPage > variablePage.showPageNum) {
			if (variablePage.pageNo == 1) {// 当前页等于第一页
				return fromFirstPagePrint();
			} else if (variablePage.pageNo == variablePage.totalPage) {// 当前页等于最后一页
				return fromLastPagePrint();
			} else {// 如果当前页：即不是首页也不是尾页
				if (variablePage.showPageNum % 2 == 0) {// 可以平分页码
					int print$No = variablePage.showPageNum / 2;
					if (variablePage.pageNo >= print$No) {
						int index$No = variablePage.pageNo - print$No;
						if (variablePage.pageNo + print$No >= variablePage.totalPage) {
							return fromLastPagePrint();
						} else {
							if (index$No == 0)
								index$No = 1;
							for (int i = index$No; i < (variablePage.showPageNum + index$No); i++) {
								if (i == variablePage.pageNo) {// 如果是当前页:不添加连接URL
									printNo += (i + variablePage.split);
								} else {
									printNo += (buildA(variablePage, i) + variablePage.split);
								}
							}
						}
					} else {
						return fromFirstPagePrint();
					}
				} else {// 打印页数不是偶数时：
					int print$No = variablePage.showPageNum / 2 + 1;
					if (variablePage.pageNo >= print$No && variablePage.pageNo + print$No < variablePage.totalPage) {
						int index$No = variablePage.pageNo - print$No + 1;
						for (int i = index$No; i < variablePage.showPageNum + index$No; i++) {
							if (i == variablePage.pageNo) {// 如果是当前页:不添加连接URL
								printNo += (i + variablePage.split);
							} else {
								printNo += (buildA(variablePage, i) + variablePage.split);
							}
						}
					} else if (variablePage.pageNo <= print$No) {// 从第一页开始
						return fromFirstPagePrint();
					} else {
						return fromLastPagePrint();
					}
				}
			}
			return (printNo);
		} else {
			return "1";
		}
	}

	public String getBackpageNum() {
		if (variablePage.pageNo <= 1) {
			return buildSpan("上一页", variablePage);
		} else {
			return buildA("上一页", (variablePage.url + (variablePage.pageNo - 1)));
		}
	}

	public String getNextpageNum() {
		if (variablePage.pageNo >= variablePage.totalPage) {
			return buildSpan("下一页", variablePage);
		} else {
			return buildA("下一页", variablePage.url + (variablePage.pageNo + 1));
		}
	}

	public String buildSpan(String text, VariablePage variablePage) {
		return "<span style=\"color:gray;\">" + text + "</span>";
	}

	public String buildA(String text, String url) {
		return "<a href=\"" + url + "\">" + text + "</a>";
	}

	public String buildA(VariablePage variablePage, int num) {
		return ("<a href=\"" + variablePage.url + num + "\">" + num + "</a>");
	}
}

public abstract class Page {
	protected VariablePage variablePage;

	public Page(VariablePage variablePage) {
		this.variablePage = variablePage;
		calculateTotalPage();
	}

	public int getStartIndex() {
		return (getValidpageNum() - 1) * variablePage.pageSize;
	}

	public String getBackpageNum() {
		if (variablePage.pageNo <= 1) {
			return buildSpan("上一页", variablePage);
		} else {
			return buildA("上一页", variablePage.getUrl() + (variablePage.pageNo - 1));
		}
	}

	public String getNextpageNum() {
		if (variablePage.pageNo >= variablePage.totalPage) {
			return buildSpan("下一页", variablePage);
		} else {
			return buildA("下一页", variablePage.getUrl() + (variablePage.pageNo + 1));
		}
	}

	/**
	 * 计算总页数
	 */
	private void calculateTotalPage() {
		if (variablePage.totalSum % variablePage.pageSize == 0) {
			variablePage.totalPage = variablePage.totalSum / variablePage.pageSize;
		} else {
			variablePage.totalPage = variablePage.totalSum / variablePage.pageSize + 1;
		}
		if (variablePage.totalPage < variablePage.pageNo) {
			variablePage.pageNo = variablePage.totalPage;
		} else if (variablePage.pageNo < 1) {
			variablePage.pageNo = 1;
		}
	}

	protected String displayAll() {
		StringBuilder sBuilder = new StringBuilder(10);
		sBuilder.append(variablePage.split);
		for (int i = 1; i <= variablePage.totalPage; i++) {
			if (i == variablePage.pageNo) {
				sBuilder.append(i + variablePage.split);
			} else {
				sBuilder.append(buildA(variablePage, i) + variablePage.split);
			}
		}
		return sBuilder.toString();
	}

	/**
	 * 抽象出分页方法
	 * 
	 * @return
	 */
	public abstract String pagination();

	/**
	 * 实现从第一页开始打印
	 * 
	 * @return
	 */
	protected final String fromFirstPagePrint() {
		StringBuffer buffer = new StringBuffer(100);
		for (int i = 1; i <= variablePage.showPageNum; i++) {
			if (i == variablePage.pageNo) {// 如果是当前页:不添加连接URL
				buffer.append(i + variablePage.split);
			} else {
				buffer.append(buildA(variablePage, i) + variablePage.split);
			}
		}
		return buffer.toString();
	}

	/**
	 * 实现从最后一页开始打印
	 * 
	 * @return
	 */
	protected final String fromLastPagePrint() {
		StringBuffer buffer = new StringBuffer(100);
		int startPage = variablePage.totalPage - (variablePage.showPageNum - 1);
		for (int i = startPage; i <= variablePage.totalPage; i++) {
			if (i == variablePage.pageNo) {// 如果是当前页:不添加连接URL
				buffer.append(i + variablePage.split);
			} else {
				buffer.append(buildA(variablePage, i) + variablePage.split);
			}
		}
		return buffer.toString();
	}

	public String getFirstNo() {
		if (isExistsPagination()) {
			return buildA("首页", variablePage.url + 1);
		} else {
			return buildSpan("首页", variablePage);
		}
	}

	/**
	 * 判断是否存在分页
	 * 
	 * @return
	 */
	private boolean isExistsPagination() {
		if (variablePage.totalSum > 1 && variablePage.totalPage > 1) {
			return true;
		}
		return false;
	}

	public String getLastNo() {
		if (isExistsPagination()) {
			return buildA("尾页", variablePage.url + variablePage.totalPage);
		} else {
			return buildSpan("尾页", variablePage);
		}
	}

	protected int getValidpageNum() {
		if (variablePage.totalPage < variablePage.pageNo) {
			return variablePage.pageNo = variablePage.totalPage;
		} else if (variablePage.pageNo < 1) {
			return variablePage.pageNo = 1;
		} else {
			return variablePage.pageNo;
		}
	}

	public VariablePage getPageContant() {
		return this.variablePage;
	}

	public abstract String buildSpan(String text, VariablePage variablePage);

	public abstract String buildA(String text, String url);

	public abstract String buildA(VariablePage variablePage, int num);
	
	public String printModifyPageSize(int pageSize){
		StringBuilder builder=new StringBuilder(100);
		builder.append("每页<input type='text' id='pageSize' style='width:20px' maxlength='2' name='pageSize'");
		if(pageSize>0){
			builder.append(" value='"+pageSize+"' ");
		}
		builder.append("/>条");
		return builder.toString();
	}
}

/**
 * 分页基础变量
 * 
 * @description
 * @DATE 2012-3-11下午10:34:00
 */
public class SimpleVariable {
	/**
	 * 显示页码
	 */
	protected int showPageNum = 10;
	/**
	 * 连接URL
	 */
	protected String url = null;
	/**
	 * 当前页码
	 */
	protected int pageNo = 1;
	/**
	 * 总页码
	 */
	protected int totalPage = 1;
	/**
	 * 总条数
	 */
	protected int totalSum = 0;
	/**
	 * 每页显示条数
	 */
	protected int pageSize = 10;

	public String getUrl() {
		return url;
	}

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

	public int getTotalPage() {
		return totalPage;
	}

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

	public int getTotalSum() {
		return totalSum;
	}

	public void setTotalSum(int totalSum) {
		this.totalSum = totalSum;
	}

	public int getPageSize() {
		return pageSize;
	}

	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}

	public int getShowPageNum() {
		return showPageNum;
	}

	public void setShowPageNum(int showPageNum) {
		this.showPageNum = showPageNum;
	}

	public int getPageNo() {
		return pageNo;
	}

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

/**
 * 分页变量
 * 
 * @description
 * @DATE 2012-3-11下午10:34:08
 */
public class VariablePage extends SimpleVariable {
	protected String split = "  ";
	protected String style = "class='page'";

	public VariablePage(int pageNo, int totalSum, int pageSize, String url) {
		pageNo = pageNo < 1 ? 1 : pageNo;
		super.pageNo = pageNo;
		this.totalSum = totalSum;
		this.url = url;
		this.pageSize = pageSize;
	}

	public VariablePage(int pageNum, int totalSum, String url) {
		pageNum = pageNum < 1 ? 1 : pageNum;
		super.pageNo = pageNum;
		this.totalSum = totalSum;
		this.url = url;
	}

	public String getSplit() {
		return split;
	}

	public void setSplit(String split) {
		this.split = split;
	}

}

#需要使用该分页标签的JSP 使用方法如下：

JSP 头部引入

<%@taglib uri="http://www.kevin.com/taglibs/page" prefix="page" %>

使用以下标签生成分页HTML代码

<page:htmlPage pageNo="${pageNo}" url="your_url"  totalSum="${totalSum}" showPage="10" pageSize="12"/>