自定义分页标签最新修改版

一、标签处理类：

/**
*  ClassName: PagerTag.java
*  created on Oct 21, 2008
*  Copyrights 2008 qjyong All rights reserved.
*  EMail: qjyong@gmail.com
*/
package com.qiujy.tags;
import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;
/**
* 自定义分页标签
* 使用方式 <my:pager pageSize="10"
*                   pageNo="1"
*                   recordCount="100"
*                   url="index.jsp" />
*
* @author qiujy
*
*/
public class PagerTag extends TagSupport {
private int pageSize = 10; // 每页要显示的记录数
private int pageNo = 1; // 页号
private int recordCount; // 总记录数
private String url; // 目的地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;
}
public void setUrl(String url) {
this.url = url;
}
// 主要的逻辑
@Override
public int doStartTag() throws JspException {
if(recordCount == 0){
return super.doStartTag();
}

// 总页数
int pageCount = (recordCount + pageSize - 1) / pageSize;
// 页号越界处理
if (pageNo > pageCount) {
pageNo = pageCount;
}
if (pageNo < 1) {
pageNo = 1;
}

StringBuilder sb = new StringBuilder();

sb.append("<form name='pageController' id='pageController' action='' method='post'>/r/n")
.append("<input type='hidden' id='pageNo' name='pageNo' value='" + pageNo + "' />/r/n");

//------------------------------------ 获取所有請求中的参数
HttpServletRequest request = (HttpServletRequest) pageContext
.getRequest();
Enumeration<String> enumeration = request.getParameterNames();
String name = null;
String value = null;
//把请求中的所有参数当作隐藏表单域在页面中写出)
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");
}
//----------------------------------------------------

sb.append(" 总共有" + pageCount + "页,")
.append("当前是第" + pageNo + "页 /r/n");

if (pageNo == 1) {
sb.append("首页");
sb.append(" ");
sb.append("上一页/r/n");
} else {
sb.append("<a href='#' onclick='turnOverPage(1)'>首页</a>/r/n");
sb.append(" ");
sb.append("<a href='#' onclick='turnOverPage(")
.append((pageNo - 1)).append(")'>上一页</a>/r/n");
}
sb.append(" ");
if (pageNo == pageCount) {
sb.append("下一页");
sb.append(" ");
sb.append("尾页/r/n");
} else {
sb.append("<a href='#' onclick='turnOverPage(")
.append((pageNo + 1)).append(")'>下一页</a>/r/n");
sb.append(" ");
sb.append("<a href='#' onclick='turnOverPage(").append(pageCount)
.append(")'>尾页</a>/r/n");
}

sb.append(" 跳到<select onChange='turnOverPage(this.value)'>/r/n");
for (int i = 1; i <= pageCount; i++) {
if (i == pageNo) {
sb.append("  <option value='")
.append(i)
.append("' selected='selected'>第")
.append(i)
.append("页</option>/r/n");
} else {
sb.append("  <option value='")
.append(i)
.append("'>第")
.append(i)
.append("页</option>/r/n");
}
}
sb.append("</select>/r/n");
sb.append(" /r/n");
sb.append("</form>/r/n");

// 生成提交表单的JS
sb.append("<script language='javascript'>/r/n");
sb.append("  //翻页函数/t/n");
sb.append("  function turnOverPage(no){/r/n");
sb.append("    var form = document.pageController;/r/n");
sb.append("    //页号越界处理/r/n");
sb.append("    if(no").append(">").append(pageCount).append(") {/r/n");
sb.append("        no=").append(pageCount).append(";/r/n");
sb.append("    }/r/n");
sb.append("    if(no").append("< 1){/r/n");
sb.append("        no=1;/r/n");
sb.append("    }/r/n");
sb.append("    form.").append("pageNo").append(".value=no;/r/n");
sb.append("    form.action='").append(url).append("';/r/n");
sb.append("    form.submit();/r/n");
sb.append("  }/r/n");
sb.append("</script>/r/n");

try {
pageContext.getOut().println(sb.toString());
} catch (IOException e) {
e.printStackTrace();
}

return super.doStartTag();
}
}

二、标签库描述文件：

<?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>2.0</tlib-version>
<short-name>my</short-name>
<uri>http://blog.csdn.net/qjyong</uri>
<tag>
<description>通用分页标签</description>
<name>pager</name>
<tag-class>com.qiujy.tags.PagerTag</tag-class>
<body-content>empty</body-content>
<attribute>
<name>pageNo</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>recordCount</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>pageSize</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>url</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>

三、把标签处理类和tld打成pager.jar包。使用时只需添加到项目的类路径中即可。

四、测试：先写一个Servlet来创建测试数据

package com.qiujy.web.servlet;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MyServlet extends HttpServlet {

public static List<String> list = new ArrayList<String>();

public MyServlet(){
for(int i = 0; i < 100; i++){
list.add("aaa" + i);
}
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String pageNoStr = request.getParameter("pageNo");
int pageNo = 1;
if(pageNoStr != null && !pageNoStr.equals("")){
pageNo = Integer.parseInt(pageNoStr);
}

int recordCount = list.size();
int pageSize = 10;
int startNo = (pageNo - 1) * pageSize;

List<String> result = list.subList(startNo, startNo + 10);

request.setAttribute("recordCount", recordCount);
request.setAttribute("pageNo", pageNo);
request.setAttribute("pageSize", pageSize);
request.setAttribute("data", result);

request.getRequestDispatcher("index.jsp").forward(request, response);
}
}

web.xml：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 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 http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <servlet>
<servlet-name>pageTestServlet</servlet-name>
<servlet-class>com.qiujy.web.servlet.MyServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>pageTestServlet</servlet-name>
<url-pattern>/testpager</url-pattern>
</servlet-mapping>

<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

页面：index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://blog.csdn.net/qjyong" prefix="q" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>PagerTag使用示例</title>
</head>

<body>
<%
List<String> list = (List<String>)request.getAttribute("data");
for(String str : list){
out.println(str + "<br/>");
}
%>

<q:pager pageNo="${pageNo}"
recordCount="${recordCount}"
pageSize="${pageSize}"
url="testpager" />
</body>
</html>

访问testpager后的效果图：



本文转自：http://blog.csdn.net/qjyong/article/details/3240303