Hallo!
Ich bin ein völliger Java-Beginner und versuche mich nun an meinem ersten Projekt. Ich möchte ein Login-Fenster über Netbeans gestalten. Dieses habe ich einem Youtube-Video nachgemacht.
Soweit geht das Fenster gut auf, doch ich erhalte leider keine Verbindung zu MySql. Hier erhalte ich folgende Meldung:
Mein Programm hat folgende Code:
Weswegen erhalte ich keine Verbindung zu MySql?
Ich bin ein völliger Java-Beginner und versuche mich nun an meinem ersten Projekt. Ich möchte ein Login-Fenster über Netbeans gestalten. Dieses habe ich einem Youtube-Video nachgemacht.
Soweit geht das Fenster gut auf, doch ich erhalte leider keine Verbindung zu MySql. Hier erhalte ich folgende Meldung:
Mein Programm hat folgende Code:
Code:
package loginforminmysql;
public class Loginforminmysql {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
new NewJFrame();
}
}
Code:
package loginforminmysql;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import java.awt.Dimension;
import java.sql.DriverManager;
import java.sql.ResultSet;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class NewJFrame extends javax.swing.JFrame{
Connection con = null;
PreparedStatement pst = null;
ResultSet rs = null;
public NewJFrame() {
initComponents();
JPanel testPanel = new JPanel();
testPanel.setPreferredSize(new Dimension(600, 400));
add(testPanel);
pack();
setTitle("PanzerHQ");
setLocation(10, 10);
setResizable(false);
setVisible(true);
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
jButton1 = new javax.swing.JButton();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
user = new javax.swing.JTextField();
pass = new javax.swing.JTextField();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBackground(new java.awt.Color(51, 153, 255));
jButton1.setText("Login");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jLabel1.setText("Benutzername:");
jLabel2.setText("Passwort:");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap(208, Short.MAX_VALUE)
.addComponent(jButton1)
.addGap(135, 135, 135))
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(89, 89, 89)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(user, javax.swing.GroupLayout.DEFAULT_SIZE, 129, Short.MAX_VALUE)
.addComponent(pass))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addGap(91, 91, 91)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabel1)
.addComponent(user, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(pass, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 72, Short.MAX_VALUE)
.addComponent(jButton1)
.addGap(56, 56, 56))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
String sql ="select * from login where username=? and password=?";
try
{
Class.forName("com.mysql.cj.jdbc.Driver").newInstance();
con = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/testsql", "root", "");
pst = (PreparedStatement) con.createStatement();
pst.setString(1, user.getText());
pst.setString(2, pass.getText());
rs = pst.executeQuery();
if(rs.next())
{
JOptionPane.showMessageDialog(null, "Benutzername und Passwort stimmen");
}
else
{
JOptionPane.showMessageDialog(null, "Benutzername und/oder Passwort sind/ist falsch");
}
}
catch(Exception ex)
{
JOptionPane.showMessageDialog(null, ex);
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new NewJFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JPanel jPanel1;
private javax.swing.JTextField pass;
private javax.swing.JTextField user;
// End of variables declaration
}Weswegen erhalte ich keine Verbindung zu MySql?
