On Tue, 21 Mar 2000, LAVAU Michel wrote:
> At this point:
>
> "rs = stmt.executeQuery("SELECT * FROM Table");"
>
> you haven't yet initialized your stmt variable: "Statement stmt;".
> You should first set 'stmt' to NULL when you declare it (in order to start
> with proper code), and moreover, you should get a valid 'Statement' instance
> with:
> "con.createStatement();", where 'con' is your "Connection" variable
> (properly instancied). Only now you can execute your query (but this does
> NOT mean you won't have a NullPointerException anymore: you still can get
> this kind of exception if your previous "con.createStatement();" statement
> failed).
I'm really sorry bothering you with this stupid mistake when I forgot
to open con. Anyway it was kind of a cut-n-pasto, when I created the
test example. The new appended file HalloNew.java which creates the
statement and does also a check, whether it worked or not.
I also included some debugging lines in the init() method. Strangely
enough they dosn't find their way to the log files :-(! I have no
clue why the initialisation fails. I marked the line which is the
last one that is sended to the browser.
Any clue?
I expect problems in the Apache-Jserv-FreeTDS configuration but have
no idea what could be wrong.
Kind regards
Andreas.
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HalloNew extends HttpServlet
// implements SingleThreadModel
{
Connection con;
ResultSet rs;
Statement stmt;
ServletOutputStream out;
public void init(ServletConfig conf) throws ServletException {
super.init(conf);
try {
Class.forName("com.internetcds.jdbc.tds.Driver");
// Class.forName("com.internetcds.jdbc.tds.SybaseDriver");
} catch (ClassNotFoundException e) {
System.err.println("CNF: " + e.getMessage());
return;
}
String url = "jdbc:freetds:sqlserver://sql03/Test";
String user = "TestUser" ;
String password = "test";
try {
con = null;
System.err.println("getConnection(" + url + ", " + user + ", " + password + ")");
con = DriverManager.getConnection(url, user, password);
if ( con == null ) System.err.println("con = null :-(((");
else System.err.println("con != null :-)");
} catch (SQLException se) {
System.err.println("SQL: " + se.getMessage());
return;
}
}
public void service (HttpServletRequest request,
HttpServletResponse res)
throws ServletException, IOException
{
// PrintWriter out;
String title = "Example Apache JServ Servlet", query;
res.setContentType("text/html");
out = res.getOutputStream();
out.println("<HTML><HEAD><TITLE>");
out.println(title);
out.println("</TITLE></HEAD><BODY bgcolor=\"#FFFFFF\">");
out.println("<H1>" + title + "</H1>");
try {
out.println("-2<br>");
if ( con == null ) out.println("con = null :-(((");
else out.println("con != null :-)");
// ^^^^^^^^^^^^^^^^
// this is the last message in the browser
// no entrys in the log files :-(
stmt = con.createStatement();
out.println("-1<br>");
} catch (SQLException e) {
out.println("Keine Verbindung " + e.getMessage());
return ;
}
out.println("0<br>");
try {
out.println("1<br>");
rs = stmt.executeQuery("SELECT * FROM Table");
out.println("2<br>");
if ( !rs.next() ) {
out.println("3<br>");
System.err.println("Error 4");
return ;
}
out.println("4<br>");
query = rs.getString("Column");
out.println("5<br>");
out.println(query);
out.println("6<br>");
} catch (SQLException se) {
out.println("SQL: " + se.getMessage());
return;
}
out.println("<H2>Gratulation<br>");
out.println("</BODY></HTML>");
out.close();
}
}
