arvindmpai

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since Nov 06, 2001
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Recent posts by arvindmpai

hi! i would like someone to help me with paging in jsp.my code uses multiple queries and the result is that when i press the next button i get a java null pointer exception.
my code is as follows:Please help,matter pretty urgent
<%@ page language ="java" import=" java.sql.* " %>
<%
String a=request.getParameter("a");
String b=request.getParameter("b");
String c=request.getParameter("c");
String d=request.getParameter("d");
String e=request.getParameter("e");
String f=request.getParameter("f");
String g=request.getParameter("g");
String h=request.getParameter("h");
String i=request.getParameter("i");

String point=request.getParameter("point");
int next,previous;
int pointer=0;
int count=0;
int maxrecords=5;

try
{

Class.forName("gjt.org.mm.mysql.Driver");

Connection myConn=DriverManager.getConnection("jdbc:mysql://servername/password/username");
Statement stmt = myConn.createStatement();
String sql="";
if(point==null)
{
next=0;
previous=0;
//previoos=previous+1;
// change next=next+1;
}
else
{
next=Integer.parseInt(point);
previous=Integer.parseInt(point);
}
sql="select * from tablename where id>="+(next+1);
if(a.length()>0 &&(a!=null))
{
sql= sql + " and a='"+a+"'";
}
if(b.length()>0 &&(b!=null)&& (!b.equals("empty")))
{
sql= sql + " and b='"+b+"'";
}
if(c.length()>0 &&(c!=null))
{
sql= sql + " and c='"+c+"'";
}
if(d.length()>0 &&(d!=null))
{
sql= sql + " and d>='"+d+"'";
}
if(e.length()>0 &&(e!=null))
{
sql= sql + " and e<='"+e+"'";
}
if(f.length()>0 &&(f!=null))
{
sql= sql + " and f>='"+f+"'";
}
if(g.length()>0 &&(g!=null))
{
sql= sql + " and g<='"+g+"'";
}
ResultSet rs=stmt.executeQuery(sql);
ResultSetMetaData rm1 = rs.getMetaData();
//out.println(sql);
%>

<TABLE WIDTH="80%" BORDER="1" ALIGN="center">
<TR>
<Th ALIGN="center" BGCOLOR="#CCFFFF"><B><%=rm1.getColumnLabel(6)%></B></Th>
<Th ALIGN="center" BGCOLOR="#CCFFFF"><B><%=rm1.getColumnLabel(7)%></B></Th>
<Th ALIGN="center" BGCOLOR="#CCFFFF"><B><%=rm1.getColumnLabel(8)%></B></Th>
</TR>
<%
if(rs.next())
{
do
{
out.println("<tr><td>"+ rs.getString(rm1.getColumnLabel(6))+ "</td><td>" + rs.getString(rm1.getColumnLabel(7)) + " </td><td>"
+ rs.getString(rm1.getColumnLabel(8)) + " </td></tr>");

//rs1.getString(rm1.getColumnlabel(1)) + " </tr></tr>");
next++;
//next--;
}while((rs.next())&(next % maxrecords !=0));
//while((rs.previous())&(next % maxrecords !=1));
}

out.println("</table>");
if(previous >1)
{
previous=previous-maxrecords;
//previous=previous+maxrecords;
out.println("<a href='http://localhost:8080/paginginjsp.jsp?point="+previous+"'> previous</a>    ");
}
if(rs.next())
{
out.println("<a href='http://localhost:8080/paginginjsp.jsp?point="+next+"'> next </a>");
}

//pw.println("</body></html>");
myConn.close();
}
catch(SQLException exp)
{
out.println("<H2>Database Error</H2> <B>" + exp.getMessage() + "</B><H4> Please Try Sometime Later</H4>");
}

%>
22 years ago
JSP