java 分页功能

1.分页工具类

　　

package com.bw.shop.util;

import java.util.List;

import com.sun.org.apache.regexp.internal.recompile;

public class PageModel {

private List list; //结果集

private int totalRecords; //查询记录

private int pageSize; //每页记录条数

private int pageNo; //当前页数

private int totalPages;	//总页数

private int previousPageNo;

private int nextPageNo;

private int bottomPage;

public PageModel(){

}

public PageModel(int pageNo,int pageSize,int totalRecords,List list){
this.pageNo = pageNo;
this.pageSize = pageSize;
this.totalRecords = totalRecords;
this.list = list;
}
public int getTotalPages(){
if (totalRecords%pageSize == 0) 
totalPages = totalRecords / pageSize;
else 
totalPages = totalRecords / pageSize + 1;

return totalPages;
}


//获取首页
public int getTopPageNo(){
return 1;
}
//上一页
public int getPreviousPageNo(){
if (pageNo<=1) {
previousPageNo = 1;
}else {
previousPageNo = pageNo - 1;
}
return previousPageNo;
}
//下一页
public int getNextPageNo() {
if (pageNo >= getBottomPageNo()) {
nextPageNo = getBottomPageNo();
} else {
nextPageNo = pageNo + 1;
}
return nextPageNo;
}

　　

　2.实现获取分页结果集和获取总的记录条数　

//取得分页的结果集合
	public List<Link> findByPage(int pageNo,int pageSize) {
		List<Link> list = new ArrayList<Link>();
		String sql = "SELECT * FROM Link   order by sort    limit "+(pageNo-1)*pageSize+","+pageSize+"   ";
		Connection conn = JdbcUtil.getConn();
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			ps = conn.prepareStatement(sql);
			rs = ps.executeQuery(); // 取得数据库端的查询结果集合
			while (rs.next()) { // 每次判断是否有下一条数据,它从标题栏开始算
				Link bean = new Link();// 每次取一行数据，就将该行数据 封装到Link对象中
				bean.setLid(rs.getInt(1));
				bean.setTitle(rs.getString(2));
				bean.setImgpath(rs.getString(3));
				bean.setUrl(rs.getString(4));
				bean.setInfo(rs.getString(5));
				bean.setIsshow(rs.getInt(6));
				bean.setSort(rs.getInt(7));
				// 将对象存入程序端的集合中
				list.add(bean);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
		JdbcUtil.closeAll(rs, ps, conn);

		return list;

	}
	
	
	//取得总的记录条数
	public int getTotalRecords() {
        int total=0;
		String sql = "SELECT count(*) FROM Link     ";
		Connection conn = JdbcUtil.getConn();
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			ps = conn.prepareStatement(sql);
			rs = ps.executeQuery(); // 取得数据库端的查询结果集合
			if (rs.next()) { // 每次判断是否有下一条数据,它从标题栏开始算
			total=rs.getInt(1);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
		JdbcUtil.closeAll(rs, ps, conn);

		return total;

	}
	

　　3.servlet操作

public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//设置当前页数，默认是第1页
		int  pageNo =Integer.parseInt( request.getParameter("pageNo")==null?"1":request.getParameter("pageNo"));
		LinkService linkService=new LinkServiceImpl();
		int totalRecords = linkService.getTotalRecords();
		//取得分页的结果集合
		List list = linkService.findByPage(pageNo, 3);
		//封装存值
		PageModel pageModel = new PageModel(pageNo, 3, totalRecords, list);
		request.setAttribute("pageModel", pageModel);
		//跳转
		  request.getRequestDispatcher("linkList.jsp").forward(request, response);
	}

　　4.赋值

<TR class="td-block" align=middle>
<TD height=19 width="100%" colSpan=4 align=right>
<a href=${pageModel.pageNo==1?"#":"LinkServlet?pageNo=1"}>  首 页 </a>
<a href="LinkServlet?pageNo=${pageModel.previousPageNo}">  上一页 </a>
 <A href="LinkServlet?pageNo=${pageModel.nextPageNo}">下一页</A> 
 <A href="LinkServlet?pageNo=${pageModel.bottomPageNo}">尾页</A> 
 ${pageModel.pageNo}/${pageModel.totalPages}  页 
<FONT color=red>${pageModel.pageSize}</FONT>条记录/页，共<FONT color=red>${pageModel.totalRecords}</FONT>条记录 
 <SELECT class="input" onchange=javascript:document.location='LinkServlet?pageNo='+this.value >
<%PageModel pageModel = (PageModel) request.getAttribute("pageModel");
for (int i = 0; i < pageModel.getTotalPages(); i++) {
out.println(" <OPTION "+((pageModel.getPageNo() == (i + 1)) ? "selected": "") + " value=" + (i + 1) + ">第"+ (i + 1) + "页</OPTION>");
}%>
<INPUT value=1 type=hidden name=forward></TD></TR>