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500 Servlet Exception

varkala prabhakar
Ranch Hand

Joined: Sep 08, 2001
Posts: 54
Hai, i written code for the guestbook, but i get 500 Servlet Exception, could any one help me where i get the error. In myprogram i have written the correct mycode .
thanx
prabhakar.

MyException:
~~~~~~~~~~~
500 Servlet Exception
java.lang.NullPointerException
at abc.MyGuestBook.doPost (MyGuestBook.java:47) (pc 247)
at javax.servlet.http.HttpServlet.service(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
(HttpServlet.java:165) (pc 263)
at javax.servlet.http.HttpServlet.service(javax.servlet.ServletRequest,javax.servlet.ServletResponse)
(HttpServlet.java:103) (pc 15)
at com.caucho.server.http.FilterChainServlet.doFilter (FilterChainServlet.java:82)
(pc 6)
at com.caucho.server.http.Invocation.service (Invocation.java:280)
(pc 288)
at com.caucho.server.http.RunnerRequest.handleRequest (RunnerRequest.java:346)
(pc 410)
at com.caucho.server.http.RunnerRequest.handleConnection (RunnerRequest.java:269)
(pc 63)
at com.caucho.server.TcpConnection.run (TcpConnection.java:140)
(pc 78)
at java.lang.Thread.run (Thread.java:504) (pc 11)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
code :
~~~~~
package abc;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.sql.*;
public class MyGuestBook extends HttpServlet {
Connection con;
public void init( ServletConfig config ) throws ServletException {
super.init(config);
try{
Class.forName("org.hsql.jdbcDriver");
con=DriverManager.getConnection("jdbc:HypersonicSQL:/members/mycode/cgiserver/DB","name","passwd");
}
catch(Exception e)
{
e.printStackTrace();
}
}// End of init

public void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException,throwable {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
System.out.println("Before the parameters");
String s1=req.getParameter("slno");
String s2=req.getParameter("name");
String s3=req.getParameter("mail");
String s4=req.getParameter("url1");
String s5=req.getParameter("city");
String s6=req.getParameter("state");
String s7=req.getParameter("country");
String s8=req.getParameter("message");
//String s1=req.getParameter("slno");
out.println("after the [arameters");
int abc=Integer.parseInt(s1);
String query="INSERT INTO guestbook(id,name,email,url1,city,state,country,comments) values("+abc+",'"+s2+"','"+s3+"','"+s4+"','"+s5+"','"+s6+"','"+s7+"','"+s8+"')";
out.println("<html><head><title> Guest Book !!</title></head><body>");
try {
out.println("Query created:\t"+query);
Statement stmt=con.createStatement();
out.println("Statement was successfull");
stmt.executeUpdate(query);
out.println("After Update");
stmt.close();
out.println("<br><b>Update Successfull</b>");
}
catch(SQLException ex) {
ex.printStackTrace();
out.println("Update Not Successfull<br>");
//String str=ex.printStackTrace();
out.println("<b><p>Exception :</b><br>"+ex+"<p>");
}
out.println("</body></html>");
out.close();
}// End of doPost
}// End of class
William Brogden
Author and all-around good cowpoke
Rancher

Joined: Mar 22, 2000
Posts: 12789
    
    5
The evidence is right in front of you:
500 Servlet Exception
java.lang.NullPointerException
at abc.MyGuestBook.doPost (MyGuestBook.java:47) (pc 247)
---------------------------------------------^
whatever you are doing on line 47, there is a null pointer.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: 500 Servlet Exception