Hi,
I tried a servlet with the same order of making connections etc, and there was
no problem. This suggests to me that it was an SQLException kicked up when you
tried to create the statement.
What error message do you get if you put a try catch around the createStatement
i.e.
:
: try {
: Statement stmt = conn.createStatement ();
: } catch (SQLException sqle) {
: System.out.println(sqle.getMessage());
: }
:
Simon
yong hu wrote:
> Hi:
> I has received your suggetion about why my JDBC-Servlet not to
> work,and set the variable conn to a public one,the code is following:
>
> import java.sql.*;
> import java.io.*;
> import java.util.Date;
> import javax.servlet.*;
> import javax.servlet.http.*;
>
> public class SJdbcTest extends HttpServlet {
> private Connection conn=null;
> public void init(ServletConfig conf) throws ServletException {
> super.init(conf);
>
> try {
> Class.forName ("oracle.jdbc.driver.OracleDriver");}
> catch (ClassNotFoundException e)
> {System.out.println ("Could not load the driver");
> e.printStackTrace ();
> }
> try{
> conn
> =DriverManager.getConnection("jdbc:oracle:oci7:","scott","tiger");}
> catch(SQLException e){System.out.println ("Could not connect
> to the driver"); }
> System.out.println("init ok!");
> }
>
> public void doGet(HttpServletRequest req, HttpServletResponse res)
> throws ServletException, IOException
> {
> ServletOutputStream out = res.getOutputStream();
>
> try{
> Statement stmt = conn.createStatement ();
> ResultSet rset = stmt.executeQuery ("select ename from emp");
> res.setContentType("text/html");
>
> out.println("<HEAD><TITLE> SJdbcTest </TITLE></HEAD><BODY>");
> out.println("<h1> SJdbcTest </h1>");
> while (rset.next ())
> out.println(rset.getString (1));
> out.println("</BODY>");
> out.close();
> rset.close();
> stmt.close();
> conn.close();}catch(SQLException e){System.out.println ("Could
> not execute SQL"); }
>
> }
> public String getServletInfo() {
> return "SJdbcTest";
> }
> }
> However it has the same question.I debug it carefully and find that
> the loading and connecting to JDBC class is right while the code
> 'Statement stmt = conn.createStatement (); ' has a exception.SO rset
> is null and throw 'NullPointerException'.
> I has another question:Why my browser's Java Cotrol(Explore4.0 and
> Netscape4.0)doesn't show the infomation which System.out.println()
> gives.
> I hope you give me further infomation.
> Thanks in advance.
> HuYong
>
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