WEB-INF/tld/commons.tld(自定义标签库的描述):
<?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>2.0</tlib-version>
<jsp-version>1.2</jsp-version>
<short-name>common</short-name>
<uri>http://xxx.cn/common/</uri>
<display-name>Common Tag</display-name>
<description>Common Tag library</description>
<tag>
<name>page</name>
<tag-class>com.xxx.common.utils.NavigationTag</tag-class>
<body-content>JSP</body-content>
<description>create navigation for paging</description>
<attribute>
<name>bean</name>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>number</name>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>url</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
NavigationTag.java(标签处理类,继承TagSupport类):
package com.xxx.common.utils;
import java.io.IOException;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;
/**
* 显示格式 上一页 1 2 3 4 5 下一页
*/
public class NavigationTag extends TagSupport { //继承TagSupport类
static final long serialVersionUID = 2372405317744358833L;
/**
* request 中用于保存Page<E> 对象的变量名,默认为“page”
*/
private String bean = "page";
/**
* 分页跳转的url地址,此属性必须
*/
private String url = null;
/**
* 显示页码数量。 分页条显示几个页码标签
*/
private int number = 5;
@Override
public int doStartTag() throws JspException {
JspWriter writer = pageContext.getOut();
HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();
Page page = (Page)request.getAttribute(bean);
if (page == null)
return SKIP_BODY;
url = resolveUrl(url, pageContext);
try {
//计算总页数
int pageCount = page.getTotal() / page.getSize();
if (page.getTotal() % page.getSize() > 0) {
pageCount++;
}
writer.print("<nav><ul class=\"pagination\">");
//显示“上一页”按钮
if (page.getPage() > 1) {
String preUrl = append(url, "page", page.getPage() - 1);
preUrl = append(preUrl, "rows", page.getSize());
writer.print("<li><a href=\"" + preUrl + "\">上一页</a></li>");
} else {
writer.print("<li class=\"disabled\"><a href=\"#\">上一页</a></li>");
}
//显示当前页码的前2页码和后两页码
//若1 则 1 2 3 4 5, 若2 则 1 2 3 4 5, 若3 则1 2 3 4 5,
//若4 则 2 3 4 5 6 ,若10 则 8 9 10 11 12
int indexPage = (page.getPage() - 2 > 0)? page.getPage() - 2 : 1;
for(int i=1; i <= number && indexPage <= pageCount; indexPage++, i++) {
if(indexPage == page.getPage()) {
writer.print( "<li class=\"active\"><a href=\"#\">"+indexPage+"<span class=\"sr-only\">(current)</span></a></li>");
continue;
}
String pageUrl = append(url, "page", indexPage);
pageUrl = append(pageUrl, "rows", page.getSize());
writer.print("<li><a href=\"" + pageUrl + "\">"+ indexPage +"</a></li>");
}
//显示“下一页”按钮
if (page.getPage() < pageCount) {
String nextUrl = append(url, "page", page.getPage() + 1);
nextUrl = append(nextUrl, "rows", page.getSize());
writer.print("<li><a href=\"" + nextUrl + "\">下一页</a></li>");
} else {
writer.print("<li class=\"disabled\"><a href=\"#\">下一页</a></li>");
}
writer.print("</nav>");
} catch (IOException e) {
e.printStackTrace();
}
return SKIP_BODY;
}
private String append(String url, String key, int value) {
return append(url, key, String.valueOf(value));
}
/**
* 为url 参加参数对儿
*
* @param url
* @param key
* @param value
* @return
*/
private String append(String url, String key, String value) {
if (url == null || url.trim().length() == 0) {
return "";
}
if (url.indexOf("?") == -1) {
url = url + "?" + key + "=" + value;
} else {
if(url.endsWith("?")) {
url = url + key + "=" + value;
} else {
url = url + "&" + key + "=" + value;
}
}
return url;
}
/**
* 为url 添加翻页请求参数
*
* @param url
* @param pageContext
* @return
* @throws javax.servlet.jsp.JspException
*/
private String resolveUrl(String url, javax.servlet.jsp.PageContext pageContext) throws JspException{
//UrlSupport.resolveUrl(url, context, pageContext)
Map params = pageContext.getRequest().getParameterMap();
for (Object key:params.keySet()) {
if ("page".equals(key) || "rows".equals(key)) continue;
Object value = params.get(key);
if (value == null) continue;
if (value.getClass().isArray()) {
url = append(url, key.toString(), ((String[])value)[0]);
} else if (value instanceof String) {
url = append(url, key.toString(), value.toString());
}
}
return url;
}
/**
* @return the bean
*/
public String getBean() {
return bean;
}
/**
* @param bean the bean to set
*/
public void setBean(String bean) {
this.bean = bean;
}
/**
* @return the url
*/
public String getUrl() {
return url;
}
/**
* @param url the url to set
*/
public void setUrl(String url) {
this.url = url;
}
public void setNumber(int number) {
this.number = number;
}
}
Demo.jsp(使用自定义标签库):
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib prefix="my" uri="http://xxx.cn/common/"%> <!-- 引入自定义标签库 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8">
<title>demo</title>
</head>
<body>
<form action="" method="post" >
<table class="table">
<thead>
<tr>
<th>ID</th>
<th>客户名称</th>
<th>客户来源</th>
<th>客户所属行业</th>
<th>客户级别</th>
<th>固定电话</th>
<th>手机</th>
<th>操作</th>
</tr>
</thead>
<tbody>
<c:forEach items="${page.rows}" var="row">
<tr>
<td>${row.cust_id}</td>
<td>${row.cust_name}</td>
<td>${row.cust_source}</td>
<td>${row.cust_industry}</td>
<td>${row.cust_level}</td>
<td>${row.cust_phone}</td>
<td>${row.cust_mobile}</td>
<td>
<a href="#" onclick="editCustomer(${row.cust_id})">修改</a>
<a href="#" onclick="deleteCustomer(${row.cust_id})">删除</a>
</td>
</tr>
</c:forEach>
</tbody>
</table>
<div>
<!-- 分页条;自定义的标签。 -->
<my:page url="${pageContext.request.contextPath }/customer/list.action" /> <!-- 自定义标签库 -->
</div>
</form>
</body>
</html>
Page.java(用到的分页类):
package com.xxx.common.utils;
import java.util.List;
public class Page<T> {
private int total; //总记录数
private int page; //当前页数
private int size; //每页显示条数
private List<T> rows;
public int getTotal() {
return total;
}
public void setTotal(int total) {
this.total = total;
}
public int getPage() {
return page;
}
public void setPage(int page) {
this.page = page;
}
public int getSize() {
return size;
}
public void setSize(int size) {
this.size = size;
}
public List<T> getRows() {
return rows;
}
public void setRows(List<T> rows) {
this.rows = rows;
}
}