turnpagequerybean.java

使用jsp开发的一个基于HSQLDB的快餐订购管理系统

package com.uiwz.db;

import java.sql.SQLException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

public class TurnPageQueryBean extends QueryBean
{
	public int curPage = 1;
	public int maxPage;
	public int maxRow;
	public int pageSize = 20;
	public String sqlStr;
	private HttpServletRequest req;
	private HttpSession session;
	TurnPageAttributes attr;
	private String formName;
	
	private boolean isFirst = true;//是否是第一次进入番页

	public TurnPageQueryBean(HttpServletRequest req)
	throws SQLException
	{
		super();
		this.req = req;
	}
	
	private void init()
	{
		formName = req.getRequestURI();
		session = req.getSession();
		try
		{
			attr = (TurnPageAttributes)session.getAttribute(TurnPageAttributes.APP_TURN_PAGE + formName);
			String s = req.getParameter("TFP");
			String jumpPage = req.getParameter("jumpPage");
			
				
			if(jumpPage != null)
			{
				sqlStr = attr.getStatement();
				isFirst = false;
				this.curPage = Integer.parseInt(jumpPage);
				this.maxRow = attr.getMaxRowNo();
			}			
			else if(attr != null && (s == null || !s.equalsIgnoreCase("true")))
			{
				sqlStr = attr.getStatement();
				isFirst = false;
				this.curPage = attr.getCurPageNo();
				this.maxRow = attr.getMaxRowNo();
			}
		}
		catch(Exception e){}
	}
	/*
	public void setSessionID(String sessionID)
	{
		this.sessionID = sessionID ;
	}
	*/
	
	public void setStatement(String sqlStr)
	{
		this.sqlStr = sqlStr;
	}
	
	public void setPageSize(int pageSize)
	{
		this.pageSize = pageSize;
	}

	public void setCurPage(int curPage)
	{
		this.curPage = curPage;
	}

	//根据总行数计算总页数
	public void countMaxPage()
	{
		if (this.maxRow % this.pageSize == 0)
		{
			this.maxPage = this.maxRow / this.pageSize;
		}
		else
		{
			this.maxPage = this.maxRow / this.pageSize + 1;
		}
	}

	private void setSessionAttrs()
	{
		if(attr == null)
			attr = new TurnPageAttributes();
		
		attr.setCurPageNo(curPage);
		attr.setMaxPageNo(maxPage);
		attr.setMaxRowNo(maxRow);
		attr.setPageSize(pageSize);
		attr.setStatement(sqlStr);
		
		session.setAttribute(TurnPageAttributes.APP_TURN_PAGE + formName, attr);
		//session.setAttribute("sessionID",sessionID);
	}

	public void execute()
	throws SQLException
	{
		init();
		setStartRow(pageSize * (curPage - 1) + 1);
		setStopRow(pageSize * curPage);
		super.setStatement(sqlStr);
		super.execute();
		if(isFirst)
			maxRow = getSumRow();
		countMaxPage();
		setSessionAttrs();
	}
}