JSP自訂分頁標籤TAG全過程_JSP編程

首先我們需要在WEB-INF/tld/目錄下建立page.tld檔案

<?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; /** * 分頁處理標籤 * * @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;// 不顯示分頁 } else if (pageSize > totalSum) { return TagSupport.SKIP_BODY;// 不顯示分頁 } 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 分頁類 * * @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 = ""; // 如果已分頁；並且頁數小於等於要顯示的頁數 if (variablePage.totalPage > 1 && variablePage.totalPage <= variablePage.showPageNum) { return displayAll(); // 如果分頁數：大於顯示的頁碼數 } else if (variablePage.totalPage > 1 && variablePage.totalPage > variablePage.showPageNum) { if (variablePage.pageNo == 1) {// 當前頁等於第一頁 return fromFirstPagePrint(); } else if (variablePage.pageNo == variablePage.totalPage) {// 當前頁等於最後一頁 return fromLastPagePrint(); } else {// 如果當前頁：即不是首頁也不是尾頁 if (variablePage.showPageNum % 2 == 0) {// 可以平分頁碼 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$No); i++) { if (i == variablePage.pageNo) {// 如果是當前頁:不添加串連URL printNo += (i + variablePage.split); } else { printNo += (buildA(variablePage, i) + variablePage.split); } } } } else { return fromFirstPagePrint(); } } else {// 列印頁數不是偶數時： int print$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) {// 如果是當前頁:不添加串連URL printNo += (i + variablePage.split); } else { printNo += (buildA(variablePage, i) + variablePage.split); } } } else if (variablePage.pageNo <= print$No) {// 從第一頁開始 return fromFirstPagePrint(); } else { return fromLastPagePrint(); } } } return (printNo); } else { return "1"; } } public String getBackpageNum() { if (variablePage.pageNo <= 1) { return buildSpan("上一頁", variablePage); } else { return buildA("上一頁", (variablePage.url + (variablePage.pageNo - 1))); } } public String getNextpageNum() { if (variablePage.pageNo >= variablePage.totalPage) { return buildSpan("下一頁", variablePage); } else { return buildA("下一頁", 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("上一頁", variablePage); } else { return buildA("上一頁", variablePage.getUrl() + (variablePage.pageNo - 1)); } } public String getNextpageNum() { if (variablePage.pageNo >= variablePage.totalPage) { return buildSpan("下一頁", variablePage); } else { return buildA("下一頁", variablePage.getUrl() + (variablePage.pageNo + 1)); } } /** * 計算總頁數 */ 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(); } /** * 抽象出分頁方法 * * @return */ public abstract String pagination(); /** * 實現從第一頁開始列印 * * @return */ protected final String fromFirstPagePrint() { StringBuffer buffer = new StringBuffer(100); for (int i = 1; i <= variablePage.showPageNum; i++) { if (i == variablePage.pageNo) {// 如果是當前頁:不添加串連URL buffer.append(i + variablePage.split); } else { buffer.append(buildA(variablePage, i) + variablePage.split); } } return buffer.toString(); } /** * 實現從最後一頁開始列印 * * @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) {// 如果是當前頁:不添加串連URL buffer.append(i + variablePage.split); } else { buffer.append(buildA(variablePage, i) + variablePage.split); } } return buffer.toString(); } public String getFirstNo() { if (isExistsPagination()) { return buildA("首頁", variablePage.url + 1); } else { return buildSpan("首頁", variablePage); } } /** * 判斷是否存在分頁 * * @return */ private boolean isExistsPagination() { if (variablePage.totalSum > 1 && variablePage.totalPage > 1) { return true; } return false; } public String getLastNo() { if (isExistsPagination()) { return buildA("尾頁", variablePage.url + variablePage.totalPage); } else { return buildSpan("尾頁", 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("每頁<input type='text' id='pageSize' style='width:20px' maxlength='2' name='pageSize'"); if(pageSize>0){ builder.append(" value='"+pageSize+"' "); } builder.append("/>條"); return builder.toString(); } }

/** * 分頁基礎變數 * * @description * @DATE 2012-3-11下午10:34:00 */ public class SimpleVariable { /** * 顯示頁碼 */ protected int showPageNum = 10; /** * 串連URL */ protected String url = null; /** * 當前頁碼 */ protected int pageNo = 1; /** * 總頁碼 */ protected int totalPage = 1; /** * 總條數 */ protected int totalSum = 0; /** * 每頁顯示條數 */ 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; } } 

/** * 分頁變數 * * @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; } }

#需要使用該分頁標籤的JSP 使用方法如下：

JSP 頭部引入

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

使用以下標籤產生分頁HTML代碼

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