一种struts分页方法

分页处理的bean类PageableResultSet.java的构造函数参数为一个ResultSet对象，即执行查询语句得到的ResultSet。其具体代码如下：




public class PageableResultSet ... extends ResultSet{




protected java.sql.ResultSet rs = null;




protected int rowsCount;




protected int pageSize;




protected int curPage;




protected String command = "";




public PageableResultSet(java.sql.ResultSet rs)




throws java.sql.SQLException ...{


if (rs == null)


throw new SQLException("given ResultSet is NULL", "user");




rs.last();//将指针移动到此 ResultSet 对象的最后一行


rowsCount = rs.getRow();//检索当前行编号


rs.beforeFirst();//将指针移动到此 ResultSet 对象的开头，正好位于第一行之前




this.rs = rs;


}






/** *//**返回当前页号


*/




public int getCurPage() ...{


return curPage;


}






/** *//**返回总页数


*/




public int getPageCount() ...{


if (rowsCount == 0)


return 0;


if (pageSize == 0)


return 1;


// calculate PageCount


double tmpD = (double) rowsCount / pageSize;


int tmpI = (int) tmpD;


if (tmpD > tmpI)


tmpI++;


return tmpI;


}






/** *//**返回当前页的记录条数


*/




public int getPageRowsCount() ...{


if (pageSize == 0)


return rowsCount;


if (getRowsCount() == 0)


return 0;


if (curPage != getPageCount())


return pageSize;


return rowsCount - (getPageCount() - 1) * pageSize;




}






/** *//**返回分页大小


*/




public int getPageSize() ...{


return pageSize;


}






/** *//**返回总记录行数


*/




public int getRowsCount() ...{


return rowsCount;


}






/** *//**转到指定页


*/




public void gotoPage(int page) ...{


if (rs == null)


return;


if (page < 1)


page = 1;


if (page > getPageCount())


page = getPageCount();


int row = (page - 1) * pageSize + 1;




try ...{


rs.absolute(row);//将指针移动到此 ResultSet 对象的给定行编号


curPage = page;




} catch (java.sql.SQLException e) ...{


}


}






/** *//**


* 转到当前页的第一条记录


* @exception java.sql.SQLException 异常说明。


*/




public void pageFirst() throws SQLException ...{


int row = (curPage - 1) * pageSize + 1;


rs.absolute(row);


}






/** *//**


* 转到当前页的最后一条记录


* @exception java.sql.SQLException 异常说明。


*/




public void pageLast() throws SQLException ...{


int row = (curPage - 1) * pageSize + getPageRowsCount();


rs.absolute(row);


}






/** *//**设置分页大小


*/




public void setPageSize(int pageSize) ...{




if (pageSize >= 0) ...{


this.pageSize = pageSize;


curPage = 1;


}


}

public boolean next() throws SQLException {
// TODO Auto-generated method stub
return rs.next();
}


}
分页action类PageAction.java的关键代码如下：




/**//*


* Generated by MyEclipse Struts


* Template path: templates/java/JavaClass.vtl


*/


package com.lyt.struts.action;




import javax.servlet.ServletContext;


import javax.servlet.http.HttpServletRequest;


import javax.servlet.http.HttpServletResponse;


import javax.servlet.http.HttpSession;


import javax.sql.DataSource;




import org.apache.struts.action.Action;


import org.apache.struts.action.ActionForm;


import org.apache.struts.action.ActionForward;


import org.apache.struts.action.ActionMapping;




import bean.*;




import common.*;




import java.sql.ResultSet;


import java.sql.SQLException;


import java.util.*;


import dao.ApplicationDAO;






/** *//**


* MyEclipse Struts


* Creation date: 07-14-2007


*


* XDoclet definition:


* @struts.action validate="true"


*/




public class PageAction extends Action ...{




/**//*


* Generated Methods


*/






/** *//**


* Method execute


* @param mapping


* @param form


* @param request


* @param response


* @return ActionForward


*/


public ActionForward execute(ActionMapping mapping, ActionForm form,




HttpServletRequest request, HttpServletResponse response) ...{




ServletContext context = servlet.getServletContext();


//从配置文件中得到数据源


DataSource dataSource = (DataSource) context.getAttribute("db");


DB db = new DB(dataSource);


HttpSession session=request.getSession();




try...{


request.setCharacterEncoding("gb2312");




}catch(Exception e)...{


e.printStackTrace();


}


UserBean user=(UserBean)session.getAttribute("usr");




if(user==null)...{


return mapping.findForward("invalidSession");


}


int staffId=user.getID();


String sappType=request.getParameter("appType");






int appType=Integer.valueOf(sappType).intValue();


ResultSet rs=ApplicationDAO.getBjsxRS(db, staffId, appType);




int pageNumber=1;




try ...{


pageNumber=Integer.parseInt(request.getParameter("pageNumber"));




} catch (Exception e) ...{


pageNumber=1;


}


PageableResultSet prs=null;




try...{


prs=new PageableResultSet(rs);




}catch(Exception e)...{


e.printStackTrace();


}


prs.setPageSize(10);


prs.gotoPage(pageNumber);




ArrayList<Application> list =new ArrayList<Application>();




try ...{




for(int i=0; i<prs.getPageRowsCount(); i++) ...{


Application app=new Application();




list.add(app);




prs.next();


}




} catch (SQLException e) ...{


e.printStackTrace();


}


request.setAttribute("totalPage",prs.getPageCount());


request.setAttribute("currentPage",prs.getCurPage());




if(list.size()>0)...{


request.setAttribute("list", list);


}


db.close();




return mapping.findForward("page");


}


}
显示分页的page.jsp代码如下：


<%@ page language="java" pageEncoding="gb2312"


contentType="text/html;charset=gb2312"%>


<%@ page import="bean.*,common.*"%>




<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html"%>


<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean"%>


<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic"%>


<%@ taglib uri="/WEB-INF/struts-nested.tld" prefix="nested"%>






<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">


<html>


<head>




<title>主页</title>


<meta http-equiv="Content-Type" content="text/html; charset=GB2312">




<style type="text/css">


<!--




.style1 ...{color: #F4F4F4}


-->


</style>


</head>




<body>


<%


int currentPage = 1, totalPage = 0;


String sappType=(String)request.getAttribute("appType");




try ...{


currentPage = (Integer)request.getAttribute("currentPage");




} catch (Exception e) ...{}




try ...{


totalPage =(Integer)request.getAttribute("totalPage");




} catch (Exception e) ...{}


%>




<table>


<caption>




</caption>


<tr>




</tr>


<logic:present name="list" scope="request">


<logic:iterate id="shixiang" name="list">


<tr>




</tr>


</logic:iterate>


</logic:present>


</table>




<center>


<p>


第


<%=currentPage %>


页，共


<%=totalPage %>


页   


<a href=/sky_6yt/page.do?pageNumber=1&&appType=<%=sappType %>>首页</a>




<%if(currentPage<=1)...{%>


上一页




<%}else...{%>


<a href=/sky_6yt/page.do?pageNumber=<%=currentPage-1 %>&&appType=<%=sappType %>>上一页</a>


<%}%>




<%if(currentPage==totalPage)...{%>


下一页




<%}else...{%>


<a href=/sky_6yt/page.do?pageNumber=<%=currentPage+1 %>&&appType=<%=sappType %>>下一页</a>


<%} %>


<a href=/sky_6yt/page.do?pageNumber=<%=totalPage %>&&appType=<%=sappType %>>末页</a>


</p>


</center>


</body>


</html>