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 {

protectedjava.sql.ResultSetrs=null;

protectedintrowsCount;

protectedintpageSize;

protectedintcurPage;

protectedStringcommand="";

publicPageableResultSet(java.sql.ResultSetrs)
throwsjava.sql.SQLException...{
if(rs==null)
thrownewSQLException("givenResultSetisNULL","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
*/
publicintgetCurPage()...{
returncurPage;
}

/***//**返回总页数
*/
publicintgetPageCount()...{
if(rowsCount==0)
return0;
if(pageSize==0)
return1;
//calculatePageCount
doubletmpD=(double)rowsCount/pageSize;
inttmpI=(int)tmpD;
if(tmpD>tmpI)
tmpI++;
returntmpI;
}

/***//**返回当前页的记录条数
*/
publicintgetPageRowsCount()...{
if(pageSize==0)
returnrowsCount;
if(getRowsCount()==0)
return0;
if(curPage!=getPageCount())
returnpageSize;
returnrowsCount-(getPageCount()-1)*pageSize;

}

/***//**返回分页大小
*/
publicintgetPageSize()...{
returnpageSize;
}

/***//**返回总记录行数
*/
publicintgetRowsCount()...{
returnrowsCount;
}

/***//**转到指定页
*/
publicvoidgotoPage(intpage)...{
if(rs==null)
return;
if(page<1)
page=1;
if(page>getPageCount())
page=getPageCount();
introw=(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.SQLExceptione)...{
}
}

/***//**
*转到当前页的第一条记录
*@exceptionjava.sql.SQLException异常说明。
*/
publicvoidpageFirst()throwsSQLException...{
introw=(curPage-1)*pageSize+1;
rs.absolute(row);
}

/***//**
*转到当前页的最后一条记录
*@exceptionjava.sql.SQLException异常说明。
*/
publicvoidpageLast()throwsSQLException...{
introw=(curPage-1)*pageSize+getPageRowsCount();
rs.absolute(row);
}

/***//**设置分页大小
*/
publicvoidsetPageSize(intpageSize)...{
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：

/**/ /*
*GeneratedbyMyEclipseStruts
*Templatepath: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;

/***/ /**
*MyEclipseStruts
*Creationdate:07-14-2007
*
*XDocletdefinition:
*@struts.actionvalidate="true"
*/
public class PageAction extends Action ... {
/**//*
*GeneratedMethods
*/

/***//**
*Methodexecute
*@parammapping
*@paramform
*@paramrequest
*@paramresponse
*@returnActionForward
*/
publicActionForwardexecute(ActionMappingmapping,ActionFormform,
HttpServletRequestrequest,HttpServletResponseresponse)...{

ServletContextcontext=servlet.getServletContext();
//从配置文件中得到数据源
DataSourcedataSource=(DataSource)context.getAttribute("db");
DBdb=newDB(dataSource);
HttpSessionsession=request.getSession();
try...{
request.setCharacterEncoding("gb2312");
}catch(Exceptione)...{
e.printStackTrace();
}
UserBeanuser=(UserBean)session.getAttribute("usr");
if(user==null)...{
returnmapping.findForward("invalidSession");
}
intstaffId=user.getID();
StringsappType=request.getParameter("appType");


intappType=Integer.valueOf(sappType).intValue();
ResultSetrs=ApplicationDAO.getBjsxRS(db,staffId,appType);

intpageNumber=1;
try...{
pageNumber=Integer.parseInt(request.getParameter("pageNumber"));
}catch(Exceptione)...{
pageNumber=1;
}
PageableResultSetprs=null;
try...{
prs=newPageableResultSet(rs);
}catch(Exceptione)...{
e.printStackTrace();
}
prs.setPageSize(10);