Filter on form.
import java.util.*;
import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
import java.sql.*;
public class Filtonform implements Filter
{
FilterConfig fcg;
public void init(FilterConfig f)
{
fcg=f;
}
public void doFilter(ServletRequest req,ServletResponse res,FilterChain ch)throws IOException,ServletException
{
PrintWriter out=res.getWriter();
res.setContentType("text/html");
String id=req.getParameter("id");
String name=req.getParameter("name");
String pass=req.getParameter("pass");
String mail=req.getParameter("mail");
if((id.length()<=0)||(name.length()<=0)||(pass.length()<=0)||(mail.length()<=0))
{
out.println("pls fill the form");
RequestDispatcher rd=req.getRequestDispatcher("form.html");
rd.include(req,res);
}
else
{
ch.doFilter(req,res);
}
}
public void destroy()
{
}
}
<filter>
<filter-name>flt1</filter-name>
<filter-class>Filtonform</filter-class>
</filter>
<filter-mapping>
<filter-name>flt1</filter-name>
<url-pattern>*.to</url-pattern>
</filter-mapping>
