pagerecord.java

自己编写的JDBC的分页的Bean文件

package pool;
 import java.sql.*;
 import javax.servlet.*;
 import javax.servlet.http.*;
 import java.io.*;

public class PageRecord  extends HttpServlet 
{
	private int pagenum=0;// the record numer of each page including
	private int currentPage=0;
	ConnectionPool connMgr = ConnectionPool.getInstance();
	Connection conn = connMgr.getConnection();

    public PageRecord(){
	    //注册驱动程序
	  
        }

	public void setPagenum(int s)
	{	
		this.pagenum=s;
	}
	public void setCurrentPage(int s)
	{
		this.currentPage=s;
	}
   
	public int getPagenum()
	{
	   return this.pagenum;
	}
	public int getCurrentPage()
	{
	   return this.currentPage;
	}
      

	

	public ResultSet getNowRs(String sql)
	{
		ResultSet trs=null;
		try{
		Statement st=conn.createStatement();
		trs=st.executeQuery(sql);
		int count=0;
		  while (count<(this.getCurrentPage()*this.getPagenum()))
		  {
			  //这里把游标向后移动到可以开始直接读取的位置。因为是静态的，只能向前读
			  //如果读不下去，就抛出异常，返回为null
			  trs.next();
			  count++;
		   }
		}catch(SQLException e)
		{
		trs=null;
		}
		return trs;
	}
        
     //这个方法写出脚注，也就是分页的信息，需要传如url信息，以及调用servlet里的request和response对象
	public void setFoot(String url,String sql,HttpServletResponse res)throws ServletException ,java.io.IOException,SQLException
	{
		PrintWriter out=res.getWriter();
		PoolBean use=new PoolBean();
			//count the page number
		int AllCount=0;
		try{
			
		//Statement st=conn.createStatement();
		ResultSet rs=use.Query(sql);		
		while (rs.next())
		  {
			  AllCount++;
		   }
		   rs.close();
		   use.freeCon();
		}catch(SQLException e)
		{
		AllCount=0;
		use.freeCon();
		}
		int pagecount=AllCount/pagenum;
		pagecount=pagecount+1;

		String foot="";
		//根据首末状态确定foot的写法
		if (this.getCurrentPage()==0)
		{
			if (pagecount==1)
			{
				foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;[首页]&nbsp;&nbsp; [上一页]&nbsp;&nbsp;[下一页]</a>&nbsp;&nbsp; [末页]";
			}else{
			    foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;[首页]&nbsp;&nbsp; [上一页]&nbsp;&nbsp;<a href="+url+"?CurrentPage="+(this.getCurrentPage()+1)+">[下一页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(pagecount-1)+">[末页]</a>";
			}
		}else{
			if (this.getCurrentPage()==(pagecount-1))
			{
				foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;<a href="+url+"?CurrentPage=0>[首页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(this.getCurrentPage()-1)+">[上一页] </a>&nbsp;&nbsp;[下一页]&nbsp;&nbsp;[末页]</a>";
			}else
				{
			    foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;<a href="+url+"?CurrentPage=0>[首页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(this.getCurrentPage()-1)+">[上一页] </a>&nbsp;&nbsp;<a href="+url+"?CurrentPage="+(this.getCurrentPage()+1)+">[下一页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(pagecount-1)+">[末页]</a>";
			   }
		}

		out.println(foot);
	}
        //这个方法写出脚注，也就是分页的信息，需要传如url信息，以及调用servlet里的request和response对象
        //这个是setSql的方式使用该Bean的时候，用来显示Foot的
	public void setFootControl(String url,String sql,String[] controlName,String[] controlValue,int conLen,HttpServletResponse res)throws ServletException ,java.io.IOException,SQLException
	{
		PrintWriter out=res.getWriter();
		PoolBean use=new PoolBean();
			//count the page number
		int AllCount=0;
		try{
			
		//Statement st=conn.createStatement();
		ResultSet rs=use.Query(sql);		
		while (rs.next())
		  {
			  AllCount++;
		   }
		   rs.close();
		   use.freeCon();
		}catch(SQLException e)
		{
		AllCount=0;
		use.freeCon();
		}
		int pagecount=AllCount/pagenum;	
        pagecount=pagecount+1;


		//以下是确定参数以及其表达式
		String control="";
		for (int z=0;z<conLen;z++ )
		{
			control=control+"&"+controlName[z]+"="+controlValue[z];
		}

		System.out.println("目前的传的值为："+control);

		String foot="";
		//根据首末状态确定foot的写法
		if (this.getCurrentPage()==0)
		{
			if (pagecount==1)
			{
				foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;[首页]&nbsp;&nbsp; [上一页]&nbsp;&nbsp;[下一页]</a>&nbsp;&nbsp; [末页]";
			}else{
			    foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;[首页]&nbsp;&nbsp; [上一页]&nbsp;&nbsp;<a href="+url+"?CurrentPage="+(this.getCurrentPage()+1)+control+">[下一页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(pagecount-1)+control+">[末页]</a>";
			    }
		}else{
			if (this.getCurrentPage()==(pagecount-1))
			{
				foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;<a href="+url+"?CurrentPage=0"+control+">[首页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(this.getCurrentPage()-1)+control+">[上一页] </a>&nbsp;&nbsp;[下一页]&nbsp;&nbsp;[末页]";
			}else
				{
			    foot="[共&nbsp;"+pagecount+"&nbsp;页]&nbsp;&nbsp;[目前&nbsp;"+(this.getCurrentPage()+1)+"&nbsp;页]&nbsp;&nbsp;<a href="+url+"?CurrentPage=0"+control+">[首页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(this.getCurrentPage()-1)+control+">[上一页] </a>&nbsp;&nbsp;<a href="+url+"?CurrentPage="+(this.getCurrentPage()+1)+control+">[下一页]</a>&nbsp;&nbsp; <a href="+url+"?CurrentPage="+(pagecount-1)+control+">[末页]</a>";
			   }
		}
        System.out.println("当前有调用setFootSql方法,foot为"+foot);
		out.println(foot);
	}

	public void freeCon()throws java.sql.SQLException
	 {
	 connMgr.freeConnection(conn);
	   }
}