derby problem

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posted 17 years ago

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Hello all,
I am using JBuilder 2007. i am running the builtin derby database. i made a servlet and tried to connect it with my database but for some reason it throws an SQL exception that

Error.java.sql.SQLException: No suitable driver

here is my code.

package testing;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
/**
 * Servlet implementation class for Servlet: RegistrationServlet
 *
 */
 public class RegistrationServlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
    /* (non-Java-doc)
 * @see javax.servlet.http.HttpServlet#HttpServlet()
 */
 private String firstName = "";
  private String lastName = "";
  private String userName = "";
  private String password = "";
public RegistrationServlet() {
super();
}

public void init() {
    try {
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
      System.out.println("JDBC driver loaded");
    }
    catch (ClassNotFoundException e) {
      System.out.println(e.toString());
    }
  }
/* (non-Java-doc)
 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
sendPageHeader(response);
    sendRegistrationForm(request, response, false);
    sendPageFooter(response);
}

/* (non-Java-doc)
 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
sendPageHeader(response);
 
    firstName = request.getParameter("firstName");
    lastName = request.getParameter("lastName");
    userName = request.getParameter("userName");
    password = request.getParameter("password");
 
    boolean error = false;
    String message = null;
    try {
      Connection con = DriverManager.getConnection("org.apache.derby.jdbc.ClientDriver");
      System.out.println("got connection");
 
      Statement s = con.createStatement();
 
      String sql = "SELECT UserName FROM Users" +
        " WHERE userName='" + fixSqlFieldValue(userName) + "'";
      ResultSet rs = s.executeQuery(sql);
      if (rs.next()) {
        rs.close();
        message = "The user name <B>" + encodeHtmlTag(userName) +
          "</B> has been taken. Please select another name.";
        error = true;
      }
      else {
        rs.close();
        sql = "INSERT INTO Users" +
          " (FirstName, LastName, UserName, Password)" +
          " VALUES" +
          " ('" +  fixSqlFieldValue(firstName) + "'," +
          " '" +  fixSqlFieldValue(lastName) + "'," +
          " '" +  fixSqlFieldValue(userName) + "'," +
          " '" +  fixSqlFieldValue(password) + "')";
        int i = s.executeUpdate(sql);
        if (i==1) {
          message = "Successfully added one user.";
        }
      }
      s.close();
      con.close();
    }
    catch (SQLException e) {
      message = "Error." + e.toString();
      error = true;
    }
    catch (Exception e) {
      message = "Error." + e.toString();
      error = true;
    }
    if (message!=null) {
      PrintWriter out = response.getWriter();
      out.println("<B>" + message + "</B><BR>");
      out.println("<HR><BR>");
    }
    if (error==true)
      sendRegistrationForm(request, response, true);
    else
      sendRegistrationForm(request, response, false);
    sendPageFooter(response);
}

private void sendPageHeader(HttpServletResponse response)
    throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    out.println("<HTML>");
    out.println("<HEAD>");
    out.println("<TITLE>Registration Page</TITLE>");
    out.println("</HEAD>");
    out.println("<BODY>");
    out.println("<CENTER>");
  }
 
  /**
   * Send the HTML page footer, i.e. the </BODY>
   * and the </HTML>
   */
  private void sendPageFooter(HttpServletResponse response)
    throws ServletException, IOException {
    PrintWriter out = response.getWriter();
    out.println("</CENTER>");
    out.println("</BODY>");
    out.println("</HTML>");
  }
 
  /**Send the form where the user can type in
   * the details for a new user
   */
  private void sendRegistrationForm(HttpServletRequest request,
    HttpServletResponse response, boolean displayPreviousValues)
    throws ServletException, IOException {
 
    PrintWriter out = response.getWriter();
    out.println("<BR><H2>Registration Page</H2>");
    out.println("<BR>Please enter the user details.");
    out.println("<BR>");
    out.println("<BR><FORM METHOD=POST>");
    out.println("<TABLE>");
    out.println("<TR>");
    out.println("<TD>First Name</TD>");
    out.print("<TD><INPUT TYPE=TEXT Name=firstName");
 
    if (displayPreviousValues)
      out.print(" VALUE=\"" + encodeHtmlTag(firstName) + "\"");
 
    out.println("></TD>");
    out.println("</TR>");
    out.println("<TR>");
    out.println("<TD>Last Name</TD>");
    out.print("<TD><INPUT TYPE=TEXT Name=lastName");
 
    if (displayPreviousValues)
      out.print(" VALUE=\"" + encodeHtmlTag(lastName) + "\"");
 
    out.println("></TD>");
    out.println("</TR>");
    out.println("<TR>");
    out.println("<TD>User Name</TD>");
    out.print("<TD><INPUT TYPE=TEXT Name=userName");
 
    if (displayPreviousValues)
      out.print(" VALUE=\"" + encodeHtmlTag(userName) + "\"");
    out.println("></TD>");
    out.println("</TR>");
    out.println("<TR>");
    out.println("<TD>Password</TD>");
    out.print("<TD><INPUT TYPE=PASSWORD Name=password");
 
    if (displayPreviousValues)
      out.print(" VALUE=\"" + encodeHtmlTag(password) + "\"");
 
    out.println("></TD>");
    out.println("</TR>");
    out.println("<TR>");
    out.println("<TD><INPUT TYPE=RESET></TD>");
    out.println("<TD><INPUT TYPE=SUBMIT></TD>");
    out.println("</TR>");
    out.println("</TABLE>");
    out.println("</FORM>");
    out.println("<BR>");
    out.println("<BR>");
  }
  public static String encodeHtmlTag(String tag) {
    if (tag==null)
      return null;
    int length = tag.length();
    StringBuffer encodedTag = new StringBuffer(2 * length);
    for (int i=0; i<length; i++) {
      char c = tag.charAt(i);
      if (c=='<')
        encodedTag.append("<");
      else if (c=='>')
        encodedTag.append(">");
      else if (c=='&')
        encodedTag.append("&");
      else if (c=='"')
        encodedTag.append(""");  //when trying to output text as tag's value as in
        // values="???".
      else if (c==' ')
        encodedTag.append(" ");
      else
        encodedTag.append(c);
 
    }
    return encodedTag.toString();
  }
 
  /**
   * This method replaces every occurrence of
   * single quote character ' with
   * two single quote characters ''
   */
  public static String fixSqlFieldValue(String value) {
    if (value==null)
      return null;
    int length = value.length();
    StringBuffer fixedValue = new StringBuffer((int) (length * 1.1));
 
    for (int i=0; i<length; i++) {
      char c = value.charAt(i);
      if (c=='\'')
        fixedValue.append("''");
      else
        fixedValue.append(c);
    }
    return fixedValue.toString();
  }
}

and here is my database code

Thanks for the help

SCJP 1.5

Jesper de Jong

Java Cowboy

Posts: 16084

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posted 17 years ago

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Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

The JDBC/ODBC bridge driver is the wrong driver for Derby. Try this:

Class.forName("org.apache.derby.jdbc.EmbeddedDriver");

Jesper's Blog - Pluralsight Author Page

Suleman zia

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Posts: 70

posted 17 years ago

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Ok i got it.

EVerything works fine. so now when i run my servlet through tomcat5.0 and try to enter the fields firstname, lastname, username, password and click on button submit it gives me an error stating table USERS does not exist. How? Why? when i can see my table USERS in the database explorer. any ideas?

SCJP 1.5

Suleman zia

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Posts: 70

posted 17 years ago

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Dont ask me how but i changed my table to USERS.posts and it worked lol looks like in derby whenever you would like to create a table you need to add .posts.

Thankyou rancer always helpful :--)

Hope to bug you for my next task

SCJP 1.5

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