In Java mysql fehler -> null

Schatti · 23. Juni 2005

Hi,

so wenn ich jetzt mein Projekt ausführe und etwas aus der DB auslesen möchte erhalte ich einen Fehler: null ! an was könnte das liegen?

greetz

schatti

elmato · 23. Juni 2005

also da gibt ca. 100000 moeglichkeiten und ohne eine etwas genauere beschreibung wird dir niemand hier weiterhelfen koennen.......

RMI_17 · 23. Juni 2005

Was willst du genau machen

Poste mal den SourceCode

MFG RMI

Schatti · 23. Juni 2005

Application1:

Code:

package frontend;

import javax.swing.UIManager;
import java.awt.*;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */

public class Application1 {
  boolean packFrame = false;

  //Construct the application
  public Application1() {
    Frame2 frame = new Frame2();
    Point p = new Point();
    //Validate frames that have preset sizes
    //Pack frames that have useful preferred size info, e.g. from their layout
    if (packFrame) {
      frame.pack();
    }
    else {
      frame.validate();
    }
    //Center the window
    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
    Dimension frameSize = frame.getSize();
    if (frameSize.height > screenSize.height) {
      frameSize.height = screenSize.height;
    }
    if (frameSize.width > screenSize.width) {
      frameSize.width = screenSize.width;
    }
    frame.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2);
    frame.setVisible(true);
  }

  //Main method
  public static void main(String[] args) {
    try {
      UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    }
    catch(Exception e) {
      e.printStackTrace();
    }
    new Application1();
  }
}

Db.java

Code:

package frontend;

import java.sql.*;
import java.awt.*;
import java.io.*;
import java.sql.SQLException;

/* <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */

public class Db {



  Frame1 frameneu;
  Frame2 Frame2;
  public void db(String lese, Frame1 frameneu) {

    Connection con = null;
    Statement sta = null;
    ResultSet rs = null;
    try {
      Class.forName("org.gjt.mm.mysql.Driver").newInstance();
      con = DriverManager.getConnection(
          "jdbc:mysql://server/db",
          "user", "psw");

      sta = con.createStatement();
      rs = sta.executeQuery(lese);

      String Name = rs.getString(1);
      String Hersteller = rs.getString(2);
      frameneu.ausgabe.setText(frameneu.ausgabe.getText() + "\n" +
                               " Name: " + " Hersteller: " +
                               Hersteller);

    }
    catch (Exception e) {
      System.err.println("Fehler: " + e.getMessage());

    }
    finally {
      try {

        if (rs != null) {
          rs.close();
        }
        if (sta != null) {
          sta.close();
        }
        if (con != null) {
          con.close();
        }
      }
      catch (SQLException e) {}
    }

  }

  private void jbInit() throws Exception {
  }

}

Frame1

Code:

package frontend;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.borland.jbcl.layout.XYLayout;
import com.borland.jbcl.layout.*;
import com.borland.dbswing.JdbComboBox;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */

public class Frame1

    extends JFrame {
  JPanel contentPane;
  JTextField eingabe = new JTextField();
  JButton suchen = new JButton();
  JComboBox jComboBox1 = new JComboBox();
  JLabel Tabelle = new JLabel();
  Db dbneu = new Db();
  //Frame2 frameedit = new Frame2();
  JScrollPane jScrollPane1 = new JScrollPane();
  JTextArea ausgabe = new JTextArea();
  //Construct the frame
  public Frame1() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      jbInit();
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }

  //Component initialization
  private void jbInit() throws Exception {
    contentPane = (JPanel)this.getContentPane();
    eingabe.setSelectionStart(11);
    eingabe.setBounds(new Rectangle(115, 44, 226, 21));
    eingabe.addActionListener(new Frame1_eingabe_actionAdapter(this));
    contentPane.setLayout(null);
    this.setSize(new Dimension(537, 369));
    this.setTitle("Frontend");
    contentPane.setDebugGraphicsOptions(0);
    suchen.setBounds(new Rectangle(292, 73, 122, 27));
    suchen.setFont(new java.awt.Font("Dialog", 1, 11));
    suchen.setText("Suchen");
    suchen.addActionListener(new Frame1_suchen_actionAdapter(this));
    jComboBox1.addActionListener(new Frame1_jComboBox1_actionAdapter(this));
    Tabelle.setFont(new java.awt.Font("Dialog", 3, 11));
    Tabelle.setText("Tabelle:");
    Tabelle.setBounds(new Rectangle(320, 21, 48, 18));
    jComboBox1.setBounds(new Rectangle(381, 22, 130, 19));
    jScrollPane1.setVerticalScrollBarPolicy(JScrollPane.
                                            VERTICAL_SCROLLBAR_ALWAYS);
    jScrollPane1.setBounds(new Rectangle(20, 112, 501, 224));
    eingabefeld.setFont(new java.awt.Font("Dialog", 3, 11));
    eingabefeld.setText("Eingabe:");
    eingabefeld.setBounds(new Rectangle(43, 42, 67, 22));
    jdbComboBox1.setBounds(new Rectangle(167, 22, 88, 19));
    jdbComboBox1.addActionListener(new Frame1_jdbComboBox1_actionAdapter(this));
    jLabel1.setFont(new java.awt.Font("Dialog", Font.BOLD | Font.ITALIC, 11));
    jLabel1.setText("Spalten:");
    jLabel1.setBounds(new Rectangle(118, 22, 50, 15));
    jButton1.setBounds(new Rectangle(46, 76, 206, 23));
    jButton1.setText("SQL Befehl");
    contentPane.add(jScrollPane1);
    contentPane.add(eingabefeld, null);
    contentPane.add(eingabe, null);
    jScrollPane1.getViewport().add(ausgabe);
    contentPane.add(jLabel1);
    contentPane.add(jComboBox1, null);
    contentPane.add(jdbComboBox1);
    contentPane.add(Tabelle, null);
    contentPane.add(suchen, null);
    contentPane.add(jButton1);
  }

  //Overridden so we can exit when window is closed
  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }

  void eingabe_actionPerformed(ActionEvent e) {

  }

  void suchen_actionPerformed(ActionEvent e) {

    ausgabe.setText("");

    String lese = "select " + eingabe.getText() + " from " +
        jComboBox1.getItemAt(jComboBox1.getSelectedIndex());
    dbneu.db(lese, this);

  }

  void aendern_actionPerformed(ActionEvent e) {
    //frameedit.ausgabe_edit.setText("");
    //String edit = "update" + jComboBox1.getItemAt(jComboBox1.getSelectedIndex()) +
    //"set"+ dbneu.rs.getString(2);
  }

  void loeschen_actionPerformed(ActionEvent e) {

  }

  int z = 0;
  JLabel eingabefeld = new JLabel();
  JdbComboBox jdbComboBox1 = new JdbComboBox();
  JLabel jLabel1 = new JLabel();
  JButton jButton1 = new JButton();
  void jComboBox1_actionPerformed(ActionEvent e) {
    String lang[] = {
        "artikel", "mitarbeiter", "lieferer"
    };
    if (z == 0) {
      for (int i = 0; i < lang.length; i++) {
        jComboBox1.addItem(lang[i]);
        z = 1;

      }
    }
  }

  public void jdbComboBox1_actionPerformed(ActionEvent e) {

  }

  class Frame1_eingabe_actionAdapter
      implements java.awt.event.ActionListener {
    Frame1 adaptee;

    Frame1_eingabe_actionAdapter(Frame1 adaptee) {
      this.adaptee = adaptee;
    }

    public void actionPerformed(ActionEvent e) {
      adaptee.eingabe_actionPerformed(e);
    }
  }

  class Frame1_suchen_actionAdapter
      implements java.awt.event.ActionListener {
    Frame1 adaptee;

    Frame1_suchen_actionAdapter(Frame1 adaptee) {
      this.adaptee = adaptee;
    }

    public void actionPerformed(ActionEvent e) {
      adaptee.suchen_actionPerformed(e);
    }
  }

  class Frame1_aendern_actionAdapter
      implements java.awt.event.ActionListener {
    Frame1 adaptee;

    Frame1_aendern_actionAdapter(Frame1 adaptee) {
      this.adaptee = adaptee;
    }

    public void actionPerformed(ActionEvent e) {
      adaptee.aendern_actionPerformed(e);
    }
  }

  class Frame1_loeschen_actionAdapter
      implements java.awt.event.ActionListener {
    Frame1 adaptee;

    Frame1_loeschen_actionAdapter(Frame1 adaptee) {
      this.adaptee = adaptee;
    }

    public void actionPerformed(ActionEvent e) {
      adaptee.loeschen_actionPerformed(e);
    }
  }

  class Frame1_jComboBox1_actionAdapter
      implements java.awt.event.ActionListener {

    Frame1 adaptee;

    Frame1_jComboBox1_actionAdapter(Frame1 adaptee) {

      this.adaptee = adaptee;
    }

    public void actionPerformed(ActionEvent e) {
      adaptee.jComboBox1_actionPerformed(e);
    }
  }
}

class Frame1_jdbComboBox1_actionAdapter
    implements ActionListener {
  private Frame1 adaptee;
  Frame1_jdbComboBox1_actionAdapter(Frame1 adaptee) {
    this.adaptee = adaptee;
  }

  public void actionPerformed(ActionEvent e) {
    adaptee.jdbComboBox1_actionPerformed(e);
  }
}

Frame2

Code:

package frontend;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */

public class Frame2
    extends JFrame {
  JTextField mysql_server = new JTextField();
  JLabel jLabel1 = new JLabel();
  JTextField mysql_user = new JTextField();
  JLabel jLabel2 = new JLabel();
  JTextField mysql_psw = new JTextField();
  JTextField mysql_db = new JTextField();
  JLabel jLabel3 = new JLabel();
  JPanel jPanel1 = new JPanel();
  GridLayout gridLayout1 = new GridLayout();
  JLabel jLabel4 = new JLabel();
  JLabel jLabel5 = new JLabel();
  JButton jButton1 = new JButton();

  public Frame2() {
    try {
      jbInit();
    }
    catch (Exception ex) {
      ex.printStackTrace();
    }
  }

  void jbInit() throws Exception {
    gridLayout1.setColumns(3);
    jLabel4.setToolTipText("");
    jLabel4.setRequestFocusEnabled(true);
    jLabel4.setText("MySQL Passwort:");
    jLabel5.setFont(new java.awt.Font("Dialog", 1, 15));
    jLabel5.setText("MySQL Zugangsdaten");
    jLabel5.setBounds(new Rectangle(160, 55, 238, 40));
    jPanel1.setBorder(null);
    jButton1.setBounds(new Rectangle(152, 262, 233, 47));
    jButton1.setText("Weiter -->");
    jButton1.addActionListener(new Frame2_jButton1_actionAdapter(this));
    jPanel1.add(jLabel1, null);
    jPanel1.add(mysql_server, null);
    jPanel1.add(jLabel2, null);
    jPanel1.add(mysql_db, null);
    jPanel1.add(jLabel3, null);
    jPanel1.add(mysql_user, null);
    jPanel1.add(jLabel4, null);
    jPanel1.add(mysql_psw, null);
    this.getContentPane().add(jLabel5, null);
    this.getContentPane().add(jButton1, null);
    this.getContentPane().add(jPanel1, null);
    this.setDefaultCloseOperation(HIDE_ON_CLOSE);
    this.setLocale(java.util.Locale.getDefault());
    this.setResizable(true);
    this.getContentPane().setLayout(null);
    jLabel1.setText("MySQL Server:");
    jLabel2.setRequestFocusEnabled(true);
    jLabel2.setText("MySQL Datenbank::");
    jLabel3.setText("MySQL Benutzer:");
    jLabel3.setRequestFocusEnabled(true);
    jLabel3.setToolTipText("");
    jPanel1.setFont(new java.awt.Font("MS Sans Serif", 0, 11));
    jPanel1.setForeground(Color.black);
    jPanel1.setAlignmentY( (float) 0.5);
    jPanel1.setDebugGraphicsOptions(0);
    jPanel1.setDoubleBuffered(true);
    jPanel1.setBounds(new Rectangle(55, 102, 399, 96));
    jPanel1.setLayout(gridLayout1);
    gridLayout1.setHgap(0);
    gridLayout1.setRows(4);
    gridLayout1.setVgap(0);
  }

  public static void main(String[] args) {
    Frame2 frame2 = new Frame2();
  }

  void jButton1_actionPerformed(ActionEvent e) {
    new Frame1().setVisible(true);
    this.setVisible(false);
  }
}

class Frame2_jButton1_actionAdapter
    implements java.awt.event.ActionListener {
  Frame2 adaptee;

  Frame2_jButton1_actionAdapter(Frame2 adaptee) {
    this.adaptee = adaptee;
  }

  public void actionPerformed(ActionEvent e) {
    adaptee.jButton1_actionPerformed(e);
  }
}

greetz schatti

zerix · 23. Juni 2005

also ich würde mal sagen, schreib mal bei der catch-anweisung bei der datenbank e.printStackTrace()

Dann müsste eigentlihc da stehen wo der fehler ist

Schatti · 23. Juni 2005

Ok muss ich mal schaun!

irgendwie kommt schon der nächste fehler

Code:

java.lang.NoClassDefFoundError: org/aspectj/lang/Signature
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:141)
	at frontend.Db.db(Db.java:28)
	at frontend.Frame1.suchen_actionPerformed(Frame1.java:104)
	at frontend.Frame1$Frame1_suchen_actionAdapter.actionPerformed(Frame1.java:159)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)
	at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)
	at java.awt.Component.processMouseEvent(Component.java:5100)
	at java.awt.Component.processEvent(Component.java:4897)
	at java.awt.Container.processEvent(Container.java:1569)
	at java.awt.Component.dispatchEventImpl(Component.java:3615)
	at java.awt.Container.dispatchEventImpl(Container.java:1627)
	at java.awt.Component.dispatchEvent(Component.java:3477)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3483)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)
	at java.awt.Container.dispatchEventImpl(Container.java:1613)
	at java.awt.Window.dispatchEventImpl(Window.java:1606)
	at java.awt.Component.dispatchEvent(Component.java:3477)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
	at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

zerix · 23. Juni 2005

hier sind fehler

Db.java zeile 28
Frame1.java zeile 104
Frame1.java zeile 159

teppi · 23. Juni 2005

Class.forName("org.gjt.mm.mysql.Driver").newInstance();

Den Treiber in die IDE eingebunden nee

..

Schatti · 23. Juni 2005

hae?

wie meinst du das?

Schatti · 25. Juni 2005

ok geht!

lag alles an einer veralteten jdk software ...

In Java mysql fehler -> null

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