struts里的分页技术。。。(还不是通用的,有点hard_code)

王朝java/jsp·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

思路:

一般在list页面才要分页

1)所以加入一个参数来判断是否分页,如pageControll=true(当然可以不用,这步)

2)建一个转用的actionform(当然页可以是普通bean,我这里只是为了页面上少写scriplet) --网上找了个改造成自己想

要的 --PageController.java(见附)

3)在处理list的action代码里加入判断是否执行 PageController.java 里面的main()方法 如:

pageControll = request.getParameter("pageControll");

//In case the parameter is null

currentPage = (request.getParameter("currentPage") == null)?(new String("0")):request.getParameter("currentPage");

//change the String type to int

cPage = Integer.parseInt( currentPage );

//first get the borad and then get it's boardItems

boardItemsList = boardForm.getBoardItems();

//fen ye

if( pageControll != null && pageControll.equals("true") ) {

PageController pg = (new PageController()).main(boardItemsList,cPage);

request.setAttribute("PageControllerForm",pg);

}

在jsp页面上写:

<bean:define id="offset" name="PageControllerForm" property="pageStartRow" type="Integer"/>

<bean:define id="size" name="PageControllerForm" property="pageSize" type="Integer"/>

<bean:define id="previousPage" name="PageControllerForm" property="previousPage" type="Integer"/>

<bean:define id="nextPage" name="PageControllerForm" property="nextPage" type="Integer"/>

<bean:define id="totalPages" name="PageControllerForm" property="totalPages" type="Integer"/>

<% String url = "/do/BoardActions?method=listItems&pageControll=true&currentPage=";%>

<logic:equal name="PageControllerForm" property="hasPrevious" value="true">

<html:link page="<%=url+1%>" paramId="id" paramName="BoardForm" paramProperty="id">

<bean:message key="common.fenye.first"/>

</html:link>

<html:link page="<%=url+previousPage%>" paramId="id" paramName="BoardForm" paramProperty="id">

<bean:message key="common.fenye.previous"/>

</html:link>

</logic:equal>

<logic:equal name="PageControllerForm" property="hasNext" value="true">

<html:link page="<%=url+nextPage%>" paramId="id" paramName="BoardForm" paramProperty="id">

<bean:message key="common.fenye.next"/>

</html:link>

<html:link page="<%=url+totalPages%>" paramId="id" paramName="BoardForm" paramProperty="id">

<bean:message key="common.fenye.last"/>

</html:link>

</logic:equal>

<logic:iterate id="boarditems" name="BoardItemsList" offset="<%=offset.toString()%>" length="<%=size.toString()%>">

附:

package com.lpeng.base;

import java.util.List;

import org.apache.struts.action.ActionForm;

public class PageController extends ActionForm {

int totalRowsAmount; //总行数

boolean rowsAmountSet; //是否设置过totalRowsAmount 1

int pageSize=10; //每页行数

int currentPage=1; //当前页码

int nextPage;

int previousPage;

int totalPages; //总页数

boolean hasNext; //是否有下一页

boolean hasPrevious; //是否有前一页

//String description;

int pageStartRow; //开始行

int pageEndRow;

public PageController(int totalRows,int cPage){

setTotalRowsAmount(totalRows,cPage);

}

public PageController(){}

public int getTotalRowsAmount() {

return totalRowsAmount;

}

public void setTotalRowsAmount(int i,int j) {

if(!this.rowsAmountSet){

totalRowsAmount = i;

totalPages=totalRowsAmount/pageSize+1;

setCurrentPage((j == 0)?totalPages:j);

this.rowsAmountSet=true;

}

}

public boolean isRowsAmountSet() {

return rowsAmountSet;

}

public void setRowsAmountSet(boolean b) {

rowsAmountSet = b;

}

public void setCurrentPage(int i) {

currentPage = i;

nextPage=currentPage+1;

previousPage=currentPage-1;

//计算当前页开始行和结束行

if(currentPage*pageSize<totalRowsAmount){

pageEndRow=currentPage*pageSize;

pageStartRow=pageEndRow-pageSize;

}else{//for the last page,这里我是为了默认的那页(最后一页)不足pagesize时也能显示pagesize这么多。。。。。。。

pageEndRow=totalRowsAmount;

pageStartRow=pageEndRow-pageSize;

}

if (nextPage>totalPages){

hasNext=false;

}else{

hasNext=true;

}

if(previousPage==0){

hasPrevious=false;

}else{

hasPrevious=true;

}

}

public int getCurrentPage() {

return currentPage;

}

public boolean isHasNext() {

return hasNext;

}

public void setHasNext(boolean b) {

hasNext = b;

}

public boolean isHasPrevious() {

return hasPrevious;

}

public void setHasPrevious(boolean b) {

hasPrevious = b;

}

public int getNextPage() {

return nextPage;

}

public void setNextPage(int i) {

nextPage = i;

}

public int getPageSize() {

return pageSize;

}

public void setPageSize(int i) {

pageSize = i;

}

public int getPreviousPage() {

return previousPage;

}

public void setPreviousPage(int i) {

previousPage = i;

}

public int getTotalPages() {

return totalPages;

}

public void setTotalPages(int i) {

totalPages = i;

}

public int getPageEndRow() {

return pageEndRow;

}

public void setPageEndRow( int pageEndRow ) {

this.pageEndRow = pageEndRow;

}

public int getPageStartRow() {

return pageStartRow;

}

public void setPageStartRow( int pageStartRow) {

this.pageStartRow = pageStartRow;

}

public PageController main(List list,int currentPage){

int rows = list.size();

PageController pc=new PageController(rows,currentPage);

return pc;

}

}

 
 
 
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