Java + Firebird connection returning Null

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Java + Firebird connection returning Null

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#1 by (3 votes)
#2 by (0 votes)

3

My connection string with the firebird database returns null.

Below is code:

public class ModuloConexao {

    public static Connection conector(){
        //criação da varáivel conexao
        Connection conexao = null;

        //chamada do driver do mysql
        String driver = "org.firebirdsql.jdbc.FBDriver";

        //Armazenando informações referente ao banco
        String url = "jdbc:firebirdsql:localhost/3050:C:/Users/Comercial3/Desktop/SMallDATEL/SMALL.FDB"; //alterar para ip de um servidor local...
        String user = "sysdba";
        String password = "masterkey";

        //Estabelecendo conexão com o banco
        try {
            Class.forName(driver);
            conexao = DriverManager.getConnection(url, user, password);
            return conexao;
        } catch (Exception e) {
            //retorno ao usuario final

            return null;
        }

    } 
}

The problem that java informs is a NullPointerException:

java.lang.NullPointerException at br.com.datelcontrole.telas.TelaPrincipal.PesquisarProducto (MainPage.java:212) at.sourceforge.net. at java.awt.Component.processKeyEvent (Unknown Source) at javax.swing.JComponent.processKeyEvent (Unknown Source) at java.awt.Component.processEvent (Unknown Source) at java.awt.Container.processEvent (Unknown Source) at java.awt.Component.dispatchEventImpl (Unknown Source) at java.awt.Container.dispatchEventImpl (Unknown Source) at java.awt.Component.dispatchEvent (Unknown Source) at java.awt.KeyboardFocusManager.redispatchEvent (Unknown Source) at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent (Unknown Source) at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent (Unknown Source) at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions (Unknown Source) at java.awt.DefaultKeyboardFocusManager.dispatchEvent (Unknown Source) at java.awt.Component.dispatchEventImpl (Unknown Source) at java.awt.Container.dispatchEventImpl (Unknown Source) at java.awt.Window.dispatchEventImpl (Unknown Source) at java.awt.Component.dispatchEvent (Unknown Source) at java.awt.EventQueue.dispatchEventImpl (Unknown Source) at java.awt.EventQueue.access $ 500 (Unknown Source) at java.awt.EventQueue $ 3.run (Unknown Source) at java.awt.EventQueue $ 3.run (Unknown Source) at java.security.AccessController.doPrivileged (Native Method) at java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege (Unknown Source) at java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege (Unknown Source) at java.awt.EventQueue $ 4.run (Unknown Source) at java.awt.EventQueue $ 4.run (Unknown Source) at java.security.AccessController.doPrivileged (Native Method) at java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege (Unknown Source) at java.awt.EventQueue.dispatchEvent (Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters (Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter (Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy (Unknown Source) at java.awt.EventDispatchThread.pumpEvents (Unknown Source) at java.awt.EventDispatchThread.pumpEvents (Unknown Source) at java.awt.EventDispatchThread.run (Unknown Source)

Here is my class that gives the error:

public class TelaPrincipal extends JFrame {

Connection conexao = null;
PreparedStatement pst = null;
ResultSet rs = null;


private JPanel contentPane;
private JTextField txtCodProd;
private JTable tblProdutos;
private JTextField txtNomeProduto;
private JTextField txtQtdAtual;
private JTextField txtQtdAtualizada;

//txtCodProd = new JTextField(100);

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                TelaPrincipal frame = new TelaPrincipal();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the frame.
 */
public TelaPrincipal() {
    setTitle("Controle Estoque - DATEL");

    conexao = ModuloConexao.conector();

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 625, 327);
    contentPane = new JPanel();
    contentPane.setBorder(new TitledBorder(null, "Estoque", TitledBorder.LEADING, TitledBorder.TOP, null, null));
    setContentPane(contentPane);





    JLabel lblCdProduto = new JLabel("C\u00F3d. Produto");

    txtCodProd = new JTextField();
    txtCodProd.addKeyListener(new KeyAdapter() {
        @Override
        public void keyReleased(KeyEvent arg0) {
            PesquisarProduto();
        }
    });
    txtCodProd.setColumns(10);

    tblProdutos = new JTable();
    tblProdutos.setModel(new DefaultTableModel(
        new Object[][] {
            {null, null, null},
            {null, null, null},
        },
        new String[] {
            "C\u00F3d.", "Descri\u00E7\u00E3o", "Quantidade Atual"
        }
    ) {
        boolean[] columnEditables = new boolean[] {
            true, false, true
        };
        public boolean isCellEditable(int row, int column) {
            return columnEditables[column];
        }
    });
    tblProdutos.getColumnModel().getColumn(1).setResizable(false);
    tblProdutos.getColumnModel().getColumn(1).setPreferredWidth(349);
    tblProdutos.getColumnModel().getColumn(2).setPreferredWidth(154);

    JLabel lblProduto = new JLabel("Produto");

    txtNomeProduto = new JTextField();
    txtNomeProduto.setEditable(false);
    txtNomeProduto.setColumns(10);

    JLabel lblQuantidadeAtual = new JLabel("Quantidade Atual");

    txtQtdAtual = new JTextField();
    txtQtdAtual.setEditable(false);
    txtQtdAtual.setColumns(10);

    JLabel lblQuantidadeAtualizada = new JLabel("Quantidade atualizada");

    txtQtdAtualizada = new JTextField();
    txtQtdAtualizada.setColumns(10);

    JButton btnAlterar = new JButton("Alterar");

    JButton btnNewButton = new JButton("Cancelar");
    btnNewButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
        }
    });

    JLabel lblNewLabel = new JLabel("");
    lblNewLabel.setIcon(new ImageIcon("C:\Users\Comercial3\Desktop\ERP\meuCantinho\src\br\com\meucantinho\icones\search.png"));
    GroupLayout gl_contentPane = new GroupLayout(contentPane);
    gl_contentPane.setHorizontalGroup(
        gl_contentPane.createParallelGroup(Alignment.LEADING)
            .addGroup(gl_contentPane.createSequentialGroup()
                .addContainerGap()
                .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
                    .addGroup(gl_contentPane.createSequentialGroup()
                        .addComponent(lblCdProduto)
                        .addPreferredGap(ComponentPlacement.RELATED)
                        .addComponent(txtCodProd, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(ComponentPlacement.RELATED)
                        .addComponent(lblNewLabel))
                    .addGroup(gl_contentPane.createSequentialGroup()
                        .addComponent(lblProduto)
                        .addPreferredGap(ComponentPlacement.RELATED)
                        .addComponent(txtNomeProduto, GroupLayout.PREFERRED_SIZE, 532, GroupLayout.PREFERRED_SIZE))
                    .addGroup(gl_contentPane.createSequentialGroup()
                        .addGroup(gl_contentPane.createParallelGroup(Alignment.TRAILING)
                            .addGroup(gl_contentPane.createSequentialGroup()
                                .addComponent(lblQuantidadeAtual)
                                .addPreferredGap(ComponentPlacement.RELATED)
                                .addComponent(txtQtdAtual, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                            .addComponent(btnAlterar, GroupLayout.PREFERRED_SIZE, 215, GroupLayout.PREFERRED_SIZE))
                        .addPreferredGap(ComponentPlacement.RELATED, 62, Short.MAX_VALUE)
                        .addGroup(gl_contentPane.createParallelGroup(Alignment.TRAILING)
                            .addGroup(gl_contentPane.createSequentialGroup()
                                .addComponent(lblQuantidadeAtualizada)
                                .addPreferredGap(ComponentPlacement.RELATED)
                                .addComponent(txtQtdAtualizada, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                                .addGap(3))
                            .addGroup(gl_contentPane.createSequentialGroup()
                                .addComponent(btnNewButton, GroupLayout.PREFERRED_SIZE, 229, GroupLayout.PREFERRED_SIZE)
                                .addGap(27))))
                    .addComponent(tblProdutos, GroupLayout.DEFAULT_SIZE, 577, Short.MAX_VALUE))
                .addContainerGap())
    );
    gl_contentPane.setVerticalGroup(
        gl_contentPane.createParallelGroup(Alignment.LEADING)
            .addGroup(gl_contentPane.createSequentialGroup()
                .addGap(20)
                .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                    .addComponent(lblCdProduto)
                    .addComponent(txtCodProd, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                    .addComponent(lblNewLabel))
                .addGap(18)
                .addComponent(tblProdutos, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                .addGap(24)
                .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                    .addComponent(lblProduto)
                    .addComponent(txtNomeProduto, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                .addGap(18)
                .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                    .addComponent(lblQuantidadeAtual)
                    .addComponent(txtQtdAtual, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                    .addComponent(lblQuantidadeAtualizada)
                    .addComponent(txtQtdAtualizada, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                .addGap(58)
                .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                    .addComponent(btnAlterar)
                    .addComponent(btnNewButton))
                .addContainerGap(13, Short.MAX_VALUE))
    );
    contentPane.setLayout(gl_contentPane);
}

public void PesquisarProduto(){

    String sql = "SELECT CODIGO, DESCRICAO FROM ESTOQUE WHERE CODIGO = ?";
    try {
        pst = conexao.prepareStatement(sql);
        pst.setString(1, txtCodProd.getText());
        rs = pst.executeQuery();

        tblProdutos.setModel(DbUtils.resultSetToTableModel(rs));

    } catch (Exception e) {
        e.printStackTrace();
    }


}

}

Could you tell me why it is returning null?

java eclipse firebird firebird-2.5

asked by anonymous 18.05.2017 / 22:09

2 answers

0

In a test here I was able to simulate this error, and I corrected it like this:

...SMALL.FDB?encoding=ISO8859_1

21.01.2018 / 19:23

findBy Doctrine How to update or insert MySQL in the same query?

score 3 · Accepted Answer

It is because some error is bursting and the execution falls in block catch where you just have to this error and return null .

try {
    Class.forName(driver);
    conexao = DriverManager.getConnection(url, user, password);
    return conexao;
} catch (Exception e) {
    // A variável 'e' tem as informações sobre o erro, por favor, não a ignore.
    return null;
}

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