日韩精品人妻系列无码AV东京热_ [原創(chuàng )]分頁(yè)技巧(基于自定義標簽 JSTL Struts) - Woden的專(zhuān)欄

[原創(chuàng )]分頁(yè)技巧(基于自定義標簽+JSTL+Struts)

看到論壇上有同學(xué)在問(wèn)關(guān)于分頁(yè)的東西,我這里把自己一些分頁(yè)的技巧整理下發(fā)上來(lái)...因為這是在實(shí)際項目使用的,,,所以跟其他一些業(yè)務(wù)方法有關(guān)聯(lián)...還有就是使用了struts和JSTL(包括EL)標簽庫...

效果如下圖:

bean代碼:

CODE:

/*
* 創(chuàng )建日期 2006-1-26
* @author Woden Wang
* power by Heatpixel.com
*/
package org.woden.model;
import org.woden.facade.IPageCutter;

public class PageCutter implements IPageCutter{

private int pageLength=10; //每頁(yè)最大顯示記錄數
private int totalRecord; //總記錄數
private int currentPage=0; //當前頁(yè)
private static final int LENGTH = 5; //分頁(yè)間隔

/**
   * 判斷當前頁(yè)是否末頁(yè)
   * @return
   */
public boolean hasNextPage()
{
return currentPage<getTotalPage();
}

/**
   * 判斷當前頁(yè)是否首頁(yè)
   * @return
   */
public boolean hasPreviousPage()
{
return currentPage>1;
}

/**
   * 判斷是否出現邏輯錯誤
   * @return
   */
public boolean hasError()
{
return (getCurrentPage()>getTotalPage()||getCurrentPage()<1);
}

/**
   * 獲取當前頁(yè)
   * @return
   */
public int getCurrentPage() {
return currentPage;
}

/**
   * 設置當前頁(yè)
   * @param currentPage
   */
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}

/**
   * 獲取當前記錄數
   * @return
   */
public int getCurrentRecord() {
if(currentPage==0)
return 0;

return pageLength*(currentPage-1);
}

/**
   * 獲取頁(yè)面長(cháng)度
   * @return
   */
public int getPageLength() {
return pageLength;
}

/**
   * 設置頁(yè)面長(cháng)度
   * @param pageLength
   */
public void setPageLength(int pageLength) {
this.pageLength = pageLength;
}

/**
   * 獲取頁(yè)面總數
   * @return
   */
public int getTotalPage() {
return (totalRecord%pageLength==0)?totalRecord/pageLength:totalRecord/pageLength+1;
}

/**
   * 獲取記錄總數
   * @return
   */
public int getTotalRecord() {
return totalRecord;
}

/**
   * 設置記錄總數
   * @param totalRecord
   */
public void setTotalRecord(int totalRecord) {
this.totalRecord = totalRecord;
}

/**
   * 頁(yè)面循環(huán)開(kāi)始
   * @return
   */
public int getBeginPage()
{
int begin = this.currentPage - LENGTH;
if(begin<=1)
return 1;
else
return begin;
}

/**
   * 頁(yè)面循環(huán)結束
   * @return
   */
public int getEndPage()
{
int end = this.currentPage + LENGTH;
if(end>=getTotalPage())
return getTotalPage();
else
return end;
}

/**
   * 第一頁(yè)
   * @return
   */
public int getFirstPage()
{
return 1;
}

/**
   * 末頁(yè)
   * @return
   */
public int getLastPage()
{
return getTotalPage();
}
}

說(shuō)明下,這個(gè)bean實(shí)現的接口是我自己定義的,如果不是太復雜的java應用的話(huà)其實(shí)不需要用接口.(有興趣了解接口的優(yōu)勢的朋友建議閱讀"門(mén)面模式"的相關(guān)文章)

標簽處理器類(lèi):

CODE:

/*
* 創(chuàng )建日期 2006-2-7
* @author Woden Wang
* power by Heatpixel.com
*/
package org.woden.controller.tag;

import org.apache.log4j.Logger;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.tagext.TagSupport;

import org.woden.facade.IPageCutter;

public class PageCut extends TagSupport{
/**
   * Logger for this class
   */
private static final Logger logger = Logger.getLogger(PageCut.class);

private IPageCutter pageBean;
private String file;

public void setFile(String file)
{
this.file = filtePage(file);
}

public void setPageBean(IPageCutter pageBean)
{
this.pageBean = pageBean;
}

/**
   * 對路徑進(jìn)行特殊處理
   * @param file
   * @return
   */
private static String filtePage(String file)
{
String querys = file.substring(file.indexOf("?")+1);
String path = file.substring(0,file.indexOf("?")+1);

String query[] = querys.split("&");
for(int i=0;i<query.length;i++)
{
if(query[i].startsWith("page=")||query[i].equals(""))
continue;

path+=query[i]+"&";
}
return path.substring(0,path.length()-1);
}

public int doStartTag()
{
HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();

if(file.equals("")||pageBean==null)
return SKIP_BODY;

try
{
request.setAttribute("path",this.file);
request.setAttribute("pageBean",pageBean);
pageContext.include("/templet/page_cutter.jsp");

}
catch (Exception e)
{
logger.warn("獲取頁(yè)面文件失敗.");
}
return SKIP_BODY;
}
}

以下是/templet/page_cutter.jsp的代碼:

CODE:

<%@ page contentType="text/html;charset=UTF-8"%>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic"%>
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c"%>


<p>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td bgcolor="#f5f5f5" height="30">
<img src="images/spacer.gif" width="10" height="8">
<bean:message key="jsp.global.cutPage.current" /><%--顯示"Current Page"--%>
<span class="title">${pageBean.currentPage}</span> of ${pageBean.totalPage}
</td>
<td align="right" bgcolor="#f5f5f5">
<bean:message key="jsp.global.cutPage.click" /><%--顯示"Click to View Page"--%>
<c:if test="${pageBean.beginPage>1}">
<html:link page="${path}" paramId="page" paramName="pageBean" paramProperty="firstPage">${pageBean.firstPage}</html:link>...</c:if>
<c:forEach begin="${pageBean.beginPage}" end="${pageBean.endPage}" step="1" var="i">
<c:if test="${i==pageBean.currentPage}">
<span class="title">${i}</span>
</c:if>
<c:if test="${i!=pageBean.currentPage}">
<html:link page="${path}" paramId="page" paramName="i">${i}</html:link>
</c:if>
</c:forEach>
<c:if test="${pageBean.endPage<pageBean.totalPage}">...<html:link page="${path}" paramId="page" paramName="pageBean" paramProperty="lastPage">${pageBean.lastPage}</html:link>
</c:if>
<img src="images/spacer.gif" width="10" height="8" border="0" />
</td>
</tr>
</table>
</p>

由于我用來(lái)struts框架,,,所以這里用到了struts的標簽...其實(shí)如果沒(méi)用struts的話(huà)也可以去處那些標簽,也就是把<html:link>改成<a href=...>,,,把<bean:message>直接改成要顯示的文字就可以了...

標簽定義(tld):

CODE:

<tag>
<name>cutPage</name>
<tag-class>org.woden.controller.tag.PageCut</tag-class>
<body-content>jsp</body-content>

<attribute>
<name>file</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>

<attribute>
<name>pageBean</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>

標簽調用文件(list.jsp),為了不影響大家閱讀,,,這里省去了部分代碼...

CODE:

<%@ page contentType="text/html;charset=UTF-8"%>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic"%>
<%@ taglib uri="http://struts.apache.org/tags-tiles" prefix="tiles"%>
<%@ taglib uri="business" prefix="business"%><%--用戶(hù)業(yè)務(wù)標簽庫,包括分頁(yè)標簽就在這里定義--%>
<bean:parameter name="page" id="currentPage" value="1" />

<%--
這里省去了部分代碼,代碼實(shí)例會(huì )在后面講解.
--%>

<table width="100%" border="0" cellpadding="3" cellspacing="1" bgcolor="#aaaaaa">
<tr style=" background-color:#eeeeee;text-align:center" class="titles">
<td height="28">
測試的循環(huán)
</td>
</tr>
<logic:iterate id="news" name="list" type="org.woden.facade.news.INews">
<%--
這里是業(yè)務(wù)循環(huán)標簽,相當于把保存在list里面的每個(gè)news對象遍歷出來(lái),
大概可以理解成:從數據庫讀出的列表數據(可能總數100條,這里讀出10條,分頁(yè)嘛)放到list里面,
并返回一個(gè)pageCutter對象,大概的demo操作我下面會(huì )給出.
--%>

<tr style=" background-color:#ffffff;text-align:center">
<td>
<%--顯示業(yè)務(wù)邏輯,,,已刪除--%>
</td>
</tr>

</logic:iterate>
</table>

<%--pageCutter是分頁(yè)對象名,這里調用標簽將分頁(yè)對象里面的內容顯示出來(lái)--%>
<business:cutPage file="${pageContext.request.servletPath}?${pageContext.request.queryString}"
pageBean="${pageCutter}" />

最后這里說(shuō)說(shuō)大概的數據庫操作:

//currentPage是外部傳進(jìn)來(lái)頁(yè)數
IPageCutter page = new PageCutter();
page.setCurrentPage(currentPage);
page.setTotalRecord(getAllNewsCount());
List list = listAllNews(page.getPageLength(),page.getCurrentRecord());
//假如page.getPageLength()等于10,page.getCurrentRecord()等于13
//listAllNews方法返回從數據庫第13條記錄開(kāi)始,到第23條記錄結束的10條記錄

最后說(shuō)明下,我是個(gè)追求良好設計模式很刻骨的人,,,所以可能會(huì )出現一些接口啊,,,門(mén)面層這類(lèi)的,,,還有為了追求所謂的MVC,,,我在JSP頁(yè)面也沒(méi)寫(xiě)任何的java語(yǔ)句/表達式,,,取而代之的是EL和JSTL...

還有,因為這個(gè)是在某實(shí)際項目中摘錄下來(lái)的,所以頁(yè)面內容都是資源文件中的,,,大家湊合著(zhù)看...

-------------------------------------------------------------------------------------下面是非MVC的分頁(yè)---------------------------------

這個(gè)是asp式的分頁(yè)...我從以前asp里面翻譯過(guò)來(lái)的...
list.jsp:

CODE:

<%@ page contentType="text/html;charset=gbk"%>
<%@ page import="java.sql.*"%>
<%Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver")
.newInstance();
String url = "jdbc:microsoft:sqlserver://localhost;DatabaseName=pagetest";
String user = "sa";
String password = "";
Connection conn = DriverManager.getConnection(url, user, password);
Statement stmt = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);

String sql = "select * from test order by id";//這里的test里面只有兩個(gè)字段,一個(gè)id(主鍵,自動(dòng)增1),一個(gè)是test(vachar)
ResultSet rs = stmt.executeQuery(sql);
rs.last();//將記錄游標移動(dòng)到最末,從而計算出共有多少條記錄,方便分頁(yè)統計
if (rs.getRow() == 0) {//如果記錄數為0就顯示"沒(méi)有內容"
%>
沒(méi)有內容
<%
} else {

//page module
int count_per_page = 5; //每頁(yè)5個(gè)記錄
int page_on = 1; //當前頁(yè)
int total_record = 0; //記錄總數
int total_page = 0; //總頁(yè)數

total_record = rs.getRow();
if (total_record % count_per_page == 0)
total_page = total_record / count_per_page;
else
total_page = total_record / count_per_page + 1;

if ("".equals(request.getParameter("page"))
|| request.getParameter("page") == null)
page_on = 1;
else
page_on = Integer.parseInt(request.getParameter("page"));

if (page_on > total_page)
page_on = total_page;
if (page_on <= 0)
page_on = 1;

rs.absolute((page_on - 1) * count_per_page + 1); //put index
%>

<%
for (int i = 1; i <= count_per_page; i++) {
%>
<p>
<%=rs.getString("test")%><%--這里循環(huán)顯示數據--%>
</p>
<%if (!rs.next())
break;

}//end for
%>

<%--show count--%>
<%
String filename = "list.jsp?";
int page_show_begin = 0; //began showed page
int page_show_end = 0; //ended showed page
int page_show_max = 6; //max showed page

if ((page_on - 1) > page_show_max)
page_show_begin = page_on - page_show_max + 1;
else
page_show_begin = 1;

if (total_page - page_on > page_show_max)
page_show_end = page_on + page_show_max - 1;
else
page_show_end = total_page;
%>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td height="30"></td>
<td bgcolor="#f5f5f5">
<img src="images/spacer.gif" width="10" height="8">
Currently Viewing Page <span class="title"><%=page_on%></span> of
<%=total_page%>
</td>
<td align="right" bgcolor="#f5f5f5">
Click to View Page:
<%if (page_show_begin != 1) {%>
<%if (page_on == 1) {%>
<span class="title"><%=page_on%></span>
<%} else {
%>
<a href="<%=filename%>page=1">1</a>
<%}%>
...
<%}%>

<%for (int a = page_show_begin; a <= page_show_end; a++) {%>
<%if (a == page_on) {%>
<span class="title"><%=a%></span>
<%} else {%>
<a href="<%=filename%>page=<%=a%>"><%=a%></a>
<%}%>

<%}%>

<%if (page_show_end != total_page) {%>
...
<%if (total_page == page_on) {%>
<span class="title"><%=page_on%></span>
<%} else {
%>
<a href="<%=filename%>page=<%=total_page%>"><%=total_page%></a>
<%}
}

%>
<img src="images/spacer.gif" width="10" height="8" border="0">
</td>
</tr>
</table>

<%--View--%>

<%}
rs.close();
stmt.close();
conn.close();

%>

建表的ddl:

CREATE TABLE [dbo].[test] (
[id] [int] IDENTITY (1, 1) NOT NULL ,
[test] [varchar] (255) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO

我這里主要想介紹分頁(yè),所以為了簡(jiǎn)單起見(jiàn),直接在頁(yè)面上連接數據庫...

具體要執行本例子的方法:隨便建個(gè)tomcat項目,,,記住要導入mssqlserver那三個(gè)JDBC驅動(dòng)就可以了...只要保證數據庫連接就可以執行了...

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