struts实现分页��理

Wed, 15 Oct 2008 10:49:00 GMT

�q�近做个学校�|�站�Q�用struts写的�Q�所以把其中分页讨论下，在做之前我们的头脑中要有一个大概的框架�Q�也��是我们怎么��h��划分各个功能模块。一般来说一个分��功能框架至��要包含如下几个部分(java class)(括号注释对应本实例中的类)�Q?br /> 1:��面元素(Order.java)。也��是一个页面要昄��的一条条的记�?br /> 2:数据(DataCollection.java)。对应一个javaBean,我看有不��前辈将获取数据与页面控制放在一�?
我本��样做不好。一来逻辑不清楚，二来对于一个控制来说应是可重用的，但放在一起就不能重用了�?br /> 3:��面��面控制�Q�PageController.java�Q�。也��是对一个页面的定义
4:��面跌��{的Action(PageAction.java).因�ؓ�q�个��面跌��{相对来说比较��单我们可以直接��承ActionForward
来达到这个目的�?br /> 5:用来昄��的View.(page.jsp)
*********************************
注：本实例是从一个客户定单中取数�?br /> *********************************

下面的我��各个部分作一个简单的介绍
1:��面元素。也��是一个页面要昄��的一条条的记�?Order.java)
�q�个Order.java没有多大意思它只是一�?#8220;定单”的定�?br />         private int orderID;　　　        定单�~�号
        private String customerID;        客户�~�号
        private Date orderDate;                下单日期
***********************************************************
/*
* Created on 2004-9-14
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package com.toad.pub;
import java.util.Date;
/**
* @author Administrator
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class Order {

        private int orderID;
        private String customerID;
        private Date orderDate;
        /**
         *
         */
        public Order() {
                // TODO Auto-generated constructor stub
        }
        /**
         * @param orderID
         * @param customerID
         * @param orderDate
         */
        public Order(int orderID, String customerID, Date orderDate) {
                this.orderID = orderID;
                this.customerID = customerID;
                this.orderDate = orderDate;
        }
        /**
         * @return Returns the customerID.
         */
        public String getCustomerID() {
                return customerID;
        }
        /**
         * @param customerID The customerID to set.
         */
        public void setCustomerID(String customerID) {
                this.customerID = customerID;
        }
        /**
         * @return Returns the orderDate.
         */
        public Date getOrderDate() {
                return orderDate;
        }
        /**
         * @param orderDate The orderDate to set.
         */
        public void setOrderDate(Date orderDate) {
                this.orderDate = orderDate;
        }
        /**
         * @return Returns the orderID.
         */
        public int getOrderID() {
                return orderID;
        }
        /**
         * @param orderID The orderID to set.
         */
        public void setOrderID(int orderID) {
                this.orderID = orderID;
        }
***********************************************************
2:数据(DataCollection.java).�q�个部分有您可以依据个�h情况来进�?br /> 自定义。我已有的环境中是用的连接池.
        private ArrayList list;  用来存放所查询到的数据
        private Connection con;　代表一个数据库�q�接。这个连�?br /> 是通过传过来的。在接下来的view中我会作介绍
***********************************************************
/*
* Created on 2004-9-15
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package com.toad.pub;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Date;
/**
* @author Administrator
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class DataCollection {

        private ArrayList list;
        private Connection con;
        /**
         *
         */
        public DataCollection() {
                list=new ArrayList();
        }
        /**
         * @return Returns the con.
         */
        public Connection getCon() {
                return con;
        }
        /**
         * @param con The con to set.
         */
        public void setCon(Connection con) {
                this.con = con;
        }
        /**
         * @return Returns the list.
         */
        public ArrayList getList() {
                return list;
        }
        /**
         * @param list The list to set.
         */
        public void setList() {

                if(this.con==null){
                        System.out.println("con is null!");
                        return;
                }
                String syntax="select orderid,customerid,orderdate from orders order by orderid asc";
                int orderID=0;
                String customerID=null;
                Date orderDate=null;
                ResultSet rs=null;
                PreparedStatement pst=null;
                try{
                        pst=con.prepareStatement(syntax);
                        rs=pst.executeQuery();
                        while(rs.next()){
                                orderID=rs.getInt(1);
                                customerID=rs.getString(2);
                                orderDate=rs.getDate(3);
                                list.add(new Order(orderID,customerID,orderDate));
                        }
                }catch(SQLException e){
                        System.out.println("SQLException occur at fetch datas !");
                }finally{
                        try{
                                rs.close();
                                con.close();
                        }catch(SQLException e){
                                System.out.println("SQLException occur at rs and con close() !");
                        }
                }
        }
}
***********************************************************
3:��面��面控制�Q�PageController.java�Q?br />         private ArrayList allItems;        保存DataCollection中的list�Q�也��是所有的数据
        private int pageNumber;                当前��늚��号
        private int lastIndexOfPage;        当前��늚�最后一个item(Order)在allItems中的index
        private int itemsPerPage;        每一��늚�定w��
        private int itemsInPage;        当前��늚�实际items(orders)
        private int lastPageNumber;        为allItems/iemsPerPage or allItems/iemsPerPage+1
        private boolean hasPrevious;        是否为第一��?br />         private boolean hasNext;        是来为最后一��?br /> ***********************************************************
/*
* Created on 2004-9-14
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package com.toad.pub;
import java.util.ArrayList;

/**
* @author Administrator
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class PageController {

        private int pageNumber;
        private int lastIndexOfPage;
        private int itemsPerPage;
        private int itemsInPage;
        private int lastPageNumber;
        private boolean hasPrevious;
        private boolean hasNext;
        private ArrayList allItems;
        /**
         * @return Returns the allItems.
         */
        public ArrayList getAllItems() {
                return allItems;
        }
        /**
         * @param allItems The allItems to set.
         */
        public void setAllItems(ArrayList allItems) {
                this.allItems = allItems;
        }
        /**
         * @return Returns the hasNext.
         */
        public boolean isHasNext() {
                return hasNext;
        }
        /**
         * @param hasNext The hasNext to set.
         */
        public void setHasNext() {
                int items=pageNumber*itemsPerPage;
                if(items>=allItems.size()){
                        this.hasNext =false;
                }else{
                        this.hasNext=true;
                }
        }
        /**
         * @return Returns the hasPrevious.
         */
        public boolean isHasPrevious() {
                return hasPrevious;
        }
        /**
         * @param hasPrevious The hasPrevious to set.
         */
        public void setHasPrevious() {
                if(pageNumber==1){
                        this.hasPrevious=false;
                }else{
                        this.hasPrevious=true;
                }
        }
        /**
         * @return Returns the itemsInPage.
         */
        public int getItemsInPage() {
                return this.itemsInPage;
        }
        /**
         * @param itemsInPage The itemsInPage to set.
         */
        public void setItemsInPage() {
                int temp=pageNumber*itemsPerPage;
                if(temp<=allItems.size()){
                        this.itemsInPage=itemsPerPage;
                }else{
                        this.itemsInPage=( allItems.size() - ((pageNumber-1)*itemsPerPage ));
                }
        }
        /**
         * @return Returns the itemsPerPage.
         */
        public int getItemsPerPage() {
                return itemsPerPage;
        }
        /**
         * @param itemsPerPage The itemsPerPage to set.
         */
        public void setItemsPerPage(int itemsPerPage) {
                this.itemsPerPage = itemsPerPage;
        }
        /**
         * @return Returns the pageNumber.
         */
        public int getPageNumber() {
                return pageNumber;
        }
        /**
         * @param pageNumber The pageNumber to set.
         */
        public void setPageNumber(int pageNumber) {
                this.pageNumber = pageNumber;
        }

        /**
         * @return Returns the lastIndexOfPage.
         */
        public int getLastIndexOfPage() {
                return lastIndexOfPage;
        }
        /**
         * @param lastIndexOfPage The lastIndexOfPage to set.
         */
        public void setLastIndexOfPage() {
                this.lastIndexOfPage =(pageNumber -1)*itemsPerPage;
        }

        /**
         * @return Returns the lastPageNumber.
         */
        public int getLastPageNumber() {
                return lastPageNumber;
        }
        /**
         * @param lastPageNumber The lastPageNumber to set.
         */
        public void setLastPageNumber() {
                if(allItems.size()%itemsPerPage==0){
                        this.lastPageNumber =allItems.size()/itemsPerPage;
                }else{
                        this.lastPageNumber =allItems.size()/itemsPerPage+1;
                }
        }
}
***********************************************************
4:��面跌��{的Action(PageAction.java).
��h��意PageAction是直接��承于ActionForward
很简单：��是�Ҏ��action=arg2.getParameter("action").trim();
的返回值来讑֮�pageNubmer和与之相��q��讑֮��?br /> 一定不能忘了调�?return super.execute(arg0, arg1, arg2, arg3);
***********************************************************
/*
* Created on 2004-9-14
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package com.toad.pub;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.ForwardAction;
import com.toad.pub.PageController;

/**
* @author Administrator
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class PageAction extends ForwardAction {

        /* (non-Javadoc)
         * @see org.apache.struts.action.Action#execute(org.apache.struts.action.ActionMapping, org.apache.struts.action.ActionForm, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
         */
        public ActionForward execute(ActionMapping arg0, ActionForm arg1,
                        HttpServletRequest arg2, HttpServletResponse arg3) throws Exception {
                // TODO Auto-generated method stub
                String action=null;
                HttpSession session=arg2.getSession(true);
                action=arg2.getParameter("action").trim();
                PageController controller=(PageController)session.getAttribute("controller");
                int pageNumber=controller.getPageNumber();
                if(action.compareToIgnoreCase("next")==0){
                        ++pageNumber;
                }else if(action.compareToIgnoreCase("pervious")==0){
                        --pageNumber;
                }else if(action.compareToIgnoreCase("first")==0){
                        pageNumber=1;
                }else if(action.compareToIgnoreCase("last")==0){
                        pageNumber=controller.getLastPageNumber();
                }
                controller.setPageNumber(pageNumber);
                controller.setHasNext();
                controller.setHasPrevious();
                controller.setItemsInPage();
                controller.setLastIndexOfPage();
                return super.execute(arg0, arg1, arg2, arg3);
        }
}
***********************************************************
5:用来昄��的View.(page.jsp)
***********************************************************
<%@ page language="java" %>
<%@ taglib prefix="html" uri="/WEB-INF/struts-html.tld"%>
<%@ taglib prefix="bean" uri="/WEB-INF/struts-bean.tld"%>
<%@ taglib prefix="logic" uri="/WEB-INF/struts-logic.tld"%>
//得到�q�接池对�?br />
//定义一个javaBean同时讑֮�数据(<% Data.setList();%>)


        <% Data.setList();%>

//定义一个PageController同时�q�行初始化请注意调用��序!





                <%
                        controller.setHasNext();
                        controller.setHasPrevious();
                        controller.setItemsInPage();
                        controller.setLastIndexOfPage();
                        controller.setLastPageNumber();
                %>


Lomboz JSP

<%int i=0;%>
Page Number:

Row Number	Order ID	Customer ID	Order Date
<%=++i%>
First	Previous	Next	Last

**************************************************************

郭旺�q?/a> 2008-10-15 18:49 发表评论

Thu, 06 Dec 2007 01:47:00 GMT

摘要: 刚学struts不久�Q�发布点感受与大家分享！阅读全文

郭旺�q?/a> 2007-12-06 09:47 发表评论

java�~�程规范�Q�学java的第一步）

Thu, 29 Nov 2007 06:57:00 GMT

摘要: 1 Java�~�程规范 1.1 命名�U�定 1.1.1 包的命名 JDK 的标准是——包名称的所有字母均��写�Q�如�Q?package myownpackage; 1.1.2 &n... 阅读全文

郭旺�q?/a> 2007-11-29 14:57 发表评论

Thu, 29 Nov 2007 06:49:00 GMT

大家好：
首先�Ƣ迎大家来我的blog--java交流�I�间做客�Q�今天是开张，以后会把我学java的感受和看法�Q�以及看到的好文章�{载过来，�q�写一些自��q��法的文章。我是一个java初学者，对java有很��厚的兴��，��其对java的框架很有兴��，现在我也是刚��h��的，所以希望一些和我一��L��朋友共同探讨�Q�也希望以后刚学习的朋友有个借鉴。所以希望他们多发表自己看法和留�a��Q�问题大家一赯��冻I��好东西大家一起分享，本blog的宗旨是资源�׃�n、共同进步�?

郭旺�q?/a> 2007-11-29 14:49 发表评论

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struts实现分页���理

java�~�程规范�Q�学java的第一步）

struts实现分页��理