orderpagelog.java

一个jsp的课程设计：电子商务网站

/*
 * OrderPageLog.java
 *
 * Created on 2007年11月25日, 下午4:53
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package shopManage;
import java.sql.*;
import java.util.ArrayList;
import java.util.Iterator;
import shopManage.PageDataBean;
import shopManage.ListOrderInfoBean;
import dbpack.dbConnect;
/**
 *
 * @author liehuo
 */
public class OrderPageLog {
    
    /** Creates a new instance of OrderPageLog */
    public OrderPageLog () {
    }
     //返回food表中记录数
	private int getAvailableCount()throws Exception{
		dbConnect conn = new dbConnect();
		int ret = 0;
		try{
			String strSql = "select count(*) from orders";
			conn.rs = conn.sat.executeQuery(strSql);
			conn.rs.next();
			ret = conn.rs.getInt(1);
		}catch(Exception e){
		}finally {
			try{			
				conn.doClose ();
			}catch (Exception ex) {
				System.out.println("关闭数据库连接出现错误");
			}
		return ret;
		}
	}
	//根据总行数计算总页数
	private int countTotalPage(int totalRows ,int rowsPerPage) {
		if(totalRows % rowsPerPage == 0) {
			return totalRows/rowsPerPage ;
		}else{
			return totalRows/rowsPerPage + 1;
		}
	}
//返回存储了指定页数据的PageDataBean对象
	public PageDataBean getPageData(String page) throws Exception{
		int rowsPerPage = 15;
		int totalRows = getAvailableCount(); //获得表中总行数
		int totalPages = countTotalPage(totalRows,rowsPerPage); //获得总页数 
		ArrayList data = new ArrayList();
		
		PageDataBean pageBean = new PageDataBean();
		
		try{
			int pageNum = Integer.parseInt(page);
                        int topNum = (pageNum-1) * rowsPerPage;
                        String strSql = null;
			dbConnect con = new dbConnect();
                        if(topNum>0){
                          strSql = "select top "+rowsPerPage+" * from orders where id not in (select top "+topNum+" id from orders order by id desc) order by id desc ";  
                        }else{
                           strSql = "select top "+rowsPerPage+" * from orders order by id desc ";
			}
			con.rs = con.sat.executeQuery (strSql);
			while(con.rs.next()) {
				ListOrderInfoBean showlist = new ListOrderInfoBean();
                                showlist.setUserid (con.rs.getString ("userid"));
                                showlist.setFoodid (con.rs.getString ("foodid"));
                                showlist.setFoodprice (con.rs.getString ("foodprice"));
                                showlist.setFoodnum (con.rs.getString ("foodnum"));
                                showlist.setId (con.rs.getInt ("id"));
                                data.add(showlist);
				showlist = null;
			}
			con.doClose();
			pageBean.setCurPage(pageNum);
			pageBean.setData(data);
			pageBean.setTotalPage(totalPages);
                        pageBean.setRowsPerPage (rowsPerPage);
			return pageBean;
		}catch(Exception e){
			System.out.println(e);
			throw e;
		}
	}
}