page.java

用JAVA再WEB上做的留言薄

/**********************************************************************
                         * Date:2007-05-03     *
                         * File:pageQuery.java *
                         * Author:jezz         *
**********************************************************************/
package wm.bean;

import wm.bean.DB;

import java.util.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.http.HttpServletRequest;

public class page{ 

int ShowPage=1; //设置想要显示的页数
int RowCount = 0; //ResultSet的记录数目 初始值
int PageCount = 0; //ResultSet分页后的总页数 初始值
int redundance=0; //设置分页最后一页的记录数 初始值
public String HttpFile;
DB db; // 操作数据库对象


public page() {
} 
int Cint(String cint)
   {
    try {
      int n;
      n= Integer.parseInt(cint);
   return n;
        }
       catch (NumberFormatException e) {
                 return 0;
        }
}
public int getCount() throws Exception{  //获取数据总数
	db=new DB();
	int count=0;
	ResultSet rs=null;
	try{
		String sql="select count(id) as count from liuyan_temp";
		rs=db.executeQuery(sql);
		if(rs.next())
			count=rs.getInt(1);
	}
	catch(Exception e){
		throw e;
	}
	finally
	{
		db.all_close();
	}
	return count;
}
//　主要工作函数，根据所给的条件从表中读取相应的记录 

public ResultSet myQuery(HttpServletRequest request,HttpServletResponse response,int PageSize) throws Exception 
{
	HttpFile=request.getRequestURI();
	RowCount=this.getCount();
	//if(Rowcount==0)无数据
	redundance=RowCount%PageSize;
	if(redundance==0){  //计算页数
		PageCount=RowCount/PageSize;
	}
	else
	{
		PageCount=(RowCount-redundance)/PageSize;
		PageCount++;
	}
	String ToPage=request.getParameter("ToPage");
	if(ToPage=="")
		ToPage="1";
	ShowPage=Cint(ToPage);
	if(ShowPage>PageCount)
		ShowPage=PageCount;
	if(ShowPage<=0)
		ShowPage=1;
	String sql="select * from liuyan_temp order by id desc limit "+(ShowPage-1)*PageSize+","+PageSize+"";
	db=new DB();
	ResultSet rs=db.executeQuery(sql);
	return rs;
		

 
}



// 显示总页数
public int getTotalPages() { 
return PageCount;
}

//显示当前所在页数
public int getCurrenPages() { 
return ShowPage;
} 
//显示数据总数
public int getRowCount(){
 return RowCount;
}
public String PageFooter() //显示上下翻页
{  
String str = "";  
int next, prev;  
prev=ShowPage-1;  
next=ShowPage+1; 
str+="<form aciont="+ HttpFile +">";
str += "查询到<span>"+getRowCount()+"</span>条记录"+
"    共<span>"+getTotalPages()+"</span>页";  
str +=" 第<span>"+getCurrenPages()+"</span>页 ";  
if(ShowPage>1) 
str += " <A href=" + HttpFile + "?ToPage=1"+">首页</A> ";  
else 
str += " 首页 ";  
if(ShowPage>1)
str += " <A href=" + HttpFile + "?ToPage=" + prev + ">上一页</A> ";  
else
str += " 上一页 ";  
if(ShowPage<PageCount)  
str += " <A href=" + HttpFile + "?ToPage=" + next + ">下一页</A> ";  
else 
str += " 下一页 ";  
if(PageCount>1&&ShowPage!=PageCount)  
str += " <A href=" + HttpFile + "?ToPage=" + PageCount + 
">尾页</A>";  
else
str += " 尾页 ";  
str+="第<input name=ToPage type=text size=2>页 <input type=submit value=GO></form>" ;
return str;  
} 
public void all_close()
{
	db.all_close();
}
}