Java mysql JDBC connection

Asked

Viewed 269 times

0

I have a problem following this video lesson:

I seem to follow what he tells me to do but the line goes red and wrong:

 con = DriverManager.getConnection("jdbc:mysql://127.0.0.1/videoAulaJDBC", "root", "");

The error that happens are as follows:

1º unreported Exception sqlException: Must be caughtor declared to be thrown ("jdbc:mysql://127.0.0.1/videoAulaJDBC", "root", "");

2º unreported Exception sqlException is Never thrown in body of correnponding Try statement } catch (Sqlexception ex){

             System.out.println("Ocorreu um erro de SQL");

Code:

package View;

import java.sql.Connection;     // Conexão 
import java.sql.DriverManager;  // Me conecte com o driver de comunicação
import java.sql.ResultSet;      // Repositório de registros vindos de uma consulta
import java.sql.SQLException;   // Tratamento de erros
import java.sql.Statement;      // Repositório para envio de registros

/**
 *
 * @author brainiac
 */
public class JCadClienteView extends javax.swing.JDialog {

    /** Creates new form NovoJDialog */
    public JCadClienteView(java.awt.Frame parent, boolean modal) {
        super(parent, modal);
        initComponents();
    }

    /** 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();
        jLabel1 = new javax.swing.JLabel();
        jPanel2 = new javax.swing.JPanel();
        jPanel3 = new javax.swing.JPanel();
        jTextField3 = new javax.swing.JTextField();
        jLabel3 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jTextField2 = new javax.swing.JTextField();
        jLabel4 = new javax.swing.JLabel();
        jTextField1 = new javax.swing.JTextField();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);

        jPanel1.setBackground(new java.awt.Color(0, 153, 153));

        jLabel1.setFont(new java.awt.Font("Trebuchet MS", 1, 24)); // NOI18N
        jLabel1.setText("Cadastro de Cliente");

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(80, 80, 80)
                .addComponent(jLabel1)
                .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()
                .addContainerGap(47, Short.MAX_VALUE)
                .addComponent(jLabel1)
                .addGap(39, 39, 39))
        );

        jPanel2.setBackground(new java.awt.Color(0, 153, 153));

        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 0, Short.MAX_VALUE)
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 31, Short.MAX_VALUE)
        );

        jPanel3.setBorder(javax.swing.BorderFactory.createTitledBorder("Dados do Cliente"));

        jLabel3.setText("Endereço");

        jLabel2.setText("Nome");

        jLabel4.setText("CPF");

        javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
        jPanel3.setLayout(jPanel3Layout);
        jPanel3Layout.setHorizontalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel3Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addGroup(jPanel3Layout.createSequentialGroup()
                        .addComponent(jLabel2)
                        .addGap(32, 32, 32)
                        .addComponent(jTextField1))
                    .addGroup(jPanel3Layout.createSequentialGroup()
                        .addComponent(jLabel3)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jTextField2))
                    .addGroup(jPanel3Layout.createSequentialGroup()
                        .addComponent(jLabel4)
                        .addGap(43, 43, 43)
                        .addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, 311, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap())
        );
        jPanel3Layout.setVerticalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel3Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 18, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(8, 8, 8)
                .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel3)
                    .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel4)
                    .addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap())
        );

        jButton1.setText("Limpar");

        jButton2.setText("Salvar");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel2, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jButton1)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addComponent(jButton2)))
                .addContainerGap(44, Short.MAX_VALUE))
            .addComponent(jPanel1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton1)
                    .addComponent(jButton2))
                .addGap(60, 60, 60)
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
        );

        pack();
    }// </editor-fold>                        

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        try {
            //Botaõ Salvar
            Class.forName("com.mysql.jdbc.Driver");
        }catch (ClassNotFoundException ex) {
            System.out.println("Não foi possível encontrar a classe");
            // Criando variável de conexão
            Connection con;
            //Connection con;

            con = DriverManager.getConnection("jdbc:mysql://127.0.0.1/videoAulaJDBC", "root", "");

        } catch (SQLException ex){

             System.out.println("Ocorreu um erro de SQL");
        }
    }                                        

    /**
     * @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(JCadClienteView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(JCadClienteView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(JCadClienteView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(JCadClienteView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //</editor-fold>

        /* Create and display the dialog */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                JCadClienteView dialog = new JCadClienteView(new javax.swing.JFrame(), true);
                dialog.addWindowListener(new java.awt.event.WindowAdapter() {
                    @Override
                    public void windowClosing(java.awt.event.WindowEvent e) {
                        System.exit(0);
                    }
                });
                dialog.setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JPanel jPanel3;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextField jTextField2;
    private javax.swing.JTextField jTextField3;
    // End of variables declaration                   
}
  • Add the error stack to the question as well. And the link to the other error is not opening.

  • Thanks Guilherme, The error is within the lines: con = Drivermanager.getConnection("jdbc:mysql://127.0.0.1/videoAulaJDBC", "root", ""); } catch (Sqlexception ex){ more precisely at, where are selected:

  • Missed you add error stack in question.

  • 1º&#xA;unreported exception sqlException: Must be caughtor declared to be thrown&#xA;&#xA;&#xA;2º&#xA;unreported exception sqlException is never thrown in body of correnponding try statement

  • Can you add in question? So it is easier for someone to help you, with all the information in question.

  • Sure, sorry, I’m new around here

Show 1 more comment

1 answer

1

Your connection line is inside the catch, when it should be inside the Try, so it generates an unreported Exception error, because this connection method can throw a checked exception, which must be treated with Try/catch or thrown with throws.

Change the method to the following:

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         

   try {
        //Botaõ Salvar
        Class.forName("com.mysql.jdbc.Driver");
        // Criando variável de conexão
        Connection con;
        con = DriverManager.getConnection("jdbc:mysql://127.0.0.1/videoAulaJDBC", "root", "");
    }catch (ClassNotFoundException ex) {
        System.out.println("Não foi possível encontrar a classe");
    } catch (SQLException ex){
        System.out.println("Ocorreu um erro de SQL");
    }
} 

Browser other questions tagged

You are not signed in. Login or sign up in order to post.