Java Zum nächsten und vorherigen Datensatz wechseln

Question

Mit dem folgenden Code kann ich zum letzten Datensatz der Datenbank und zum ersten Datensatz der Datenbank wechseln. Ich erstelle die next() -Methode für den Wechsel zum nächsten Datensatz. Es bewegt sich von dem ersten Datensatz zu dem zweiten Datensatz, aber es einen dieses Fehlers (SQLException Ergebnisses zeigt nach dem letzten Zeile gesetzt. Ich nicht mit meinem Projekt fortgesetzt werden kann, bis ich Aufzeichnungen nächste und vorherigen bewegen kann. Jede Hilfe Bitte

public void CreateResultSet(){ 
    try{ 
     stmt = connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE); 
     String sql = "select * from OAUTOPARTS_PRODUCT"; 
     stmt.executeQuery(sql); 
     rs = stmt.getResultSet(); 

    }catch(Exception e){ 

     JOptionPane.showMessageDialog(null, e); 
    } 

} 

public void first(){ 
    CreateResultSet(); 
    try{ 
      rs.first(); 
      String add1 = rs.getNString("PRODUCT_ID"); 
      txtPartNumber.setText(add1); 
      String add2 = rs.getNString("PRODUCT_NAME"); 
      txtPartName.setText(add2); 
      String add3 = rs.getNString("COST"); 
      txtPrice.setText(add3); 

    }catch(Exception e){ 
     JOptionPane.showMessageDialog(null, e); 
    } 

} 

public void next(){ 
    CreateResultSet(); 
    try{         
     while(rs.next()){ 
      rs.next(); 
      String add1 = rs.getNString("PRODUCT_ID"); 
      txtPartNumber.setText(add1); 
      String add2 = rs.getNString("PRODUCT_NAME"); 
      txtPartName.setText(add2); 
      String add3 = rs.getNString("COST"); 
      txtPrice.setText(add3); 
     } 
    }catch(Exception e){ 

     JOptionPane.showMessageDialog(null, e); 
    } 


} 

    public void last(){ 
    CreateResultSet(); 
    try{ 
     rs.last(); 
      String add1 = rs.getNString("PRODUCT_ID"); 
      txtPartNumber.setText(add1); 
      String add2 = rs.getNString("PRODUCT_NAME"); 
      txtPartName.setText(add2); 
      String add3 = rs.getNString("COST"); 
      txtPrice.setText(add3); 

    }catch(Exception e){ 
     JOptionPane.showMessageDialog(null, e); 
    } 

} 

/** 
* 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() { 

    txtPartNumber = new javax.swing.JTextField(); 
    txtPartName = new javax.swing.JTextField(); 
    txtPrice = new javax.swing.JTextField(); 
    btnFirst = new javax.swing.JButton(); 
    btnLast = new javax.swing.JButton(); 
    btnNext = new javax.swing.JButton(); 

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 

    btnFirst.setText("First"); 
    btnFirst.addActionListener(new java.awt.event.ActionListener() { 
     public void actionPerformed(java.awt.event.ActionEvent evt) { 
      btnFirstActionPerformed(evt); 
     } 
    }); 

    btnLast.setText("Last"); 
    btnLast.addActionListener(new java.awt.event.ActionListener() { 
     public void actionPerformed(java.awt.event.ActionEvent evt) { 
      btnLastActionPerformed(evt); 
     } 
    }); 

    btnNext.setText("Next"); 
    btnNext.addActionListener(new java.awt.event.ActionListener() { 
     public void actionPerformed(java.awt.event.ActionEvent evt) { 
      btnNextActionPerformed(evt); 
     } 
    }); 

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
    getContentPane().setLayout(layout); 
    layout.setHorizontalGroup(
     layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
     .addGroup(layout.createSequentialGroup() 
      .addGap(144, 144, 144) 
      .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) 
       .addComponent(btnFirst, javax.swing.GroupLayout.PREFERRED_SIZE, 139, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
        .addComponent(txtPartNumber, javax.swing.GroupLayout.PREFERRED_SIZE, 152, javax.swing.GroupLayout.PREFERRED_SIZE) 
        .addComponent(txtPartName, javax.swing.GroupLayout.PREFERRED_SIZE, 152, javax.swing.GroupLayout.PREFERRED_SIZE) 
        .addComponent(txtPrice, javax.swing.GroupLayout.PREFERRED_SIZE, 152, javax.swing.GroupLayout.PREFERRED_SIZE)) 
       .addComponent(btnNext, javax.swing.GroupLayout.PREFERRED_SIZE, 139, javax.swing.GroupLayout.PREFERRED_SIZE)) 
      .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) 
      .addComponent(btnLast, javax.swing.GroupLayout.PREFERRED_SIZE, 139, javax.swing.GroupLayout.PREFERRED_SIZE) 
      .addContainerGap(89, Short.MAX_VALUE)) 
    ); 
    layout.setVerticalGroup(
     layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
     .addGroup(layout.createSequentialGroup() 
      .addGap(78, 78, 78) 
      .addComponent(txtPartNumber, javax.swing.GroupLayout.PREFERRED_SIZE, 53, javax.swing.GroupLayout.PREFERRED_SIZE) 
      .addGap(18, 18, 18) 
      .addComponent(txtPartName, javax.swing.GroupLayout.PREFERRED_SIZE, 53, javax.swing.GroupLayout.PREFERRED_SIZE) 
      .addGap(18, 18, 18) 
      .addComponent(txtPrice, javax.swing.GroupLayout.PREFERRED_SIZE, 53, javax.swing.GroupLayout.PREFERRED_SIZE) 
      .addGap(31, 31, 31) 
      .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
       .addComponent(btnFirst, javax.swing.GroupLayout.PREFERRED_SIZE, 44, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addComponent(btnLast, javax.swing.GroupLayout.PREFERRED_SIZE, 44, javax.swing.GroupLayout.PREFERRED_SIZE)) 
      .addGap(31, 31, 31) 
      .addComponent(btnNext, javax.swing.GroupLayout.PREFERRED_SIZE, 44, javax.swing.GroupLayout.PREFERRED_SIZE) 
      .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
    ); 

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

private void btnLastActionPerformed(java.awt.event.ActionEvent evt) {           
    last(); 
}          

private void btnFirstActionPerformed(java.awt.event.ActionEvent evt) {           
    first(); 
}           

private void btnNextActionPerformed(java.awt.event.ActionEvent evt) {           
    next(); 
}    

Answer 1

die Sie interessieren.

private void updateForm() { 
    String add1 = rs.getNString("PRODUCT_ID"); 
    txtPartNumber.setText(add1); 
    String add2 = rs.getNString("PRODUCT_NAME"); 
    txtPartName.setText(add2); 
    String add3 = rs.getNString("COST"); 
    txtPrice.setText(add3); 
} 

public void first() { 
    try { 
     if (rs.first()) { 
      updateForm(); 
     } 
    } catch (Exception e) { 
     JOptionPane.showMessageDialog(null, e); 
    } 
} 

public void next() { 
    try { 
     if (rs.next()) { 
      updateForm(); 
     } 
    } catch (Exception e) { 
     JOptionPane.showMessageDialog(null, e); 
    } 

} 

public void last() { 
    try { 
     if (rs.last()) { 
      updateForm(); 
     } 
    } catch (Exception e) { 
     JOptionPane.showMessageDialog(null, e); 
    } 

} 

Und CreateResultSet() im Konstruktor Ihrer Klasse bewegen, so nur einmal erstellt wird, das heißt

ich habe die Aktualisierung in einer privaten Methode herausgerechnet, die in aufgerufen wird Ihre first, next und last Methode.

Ich habe das: Hier sollte die CreateResultSet() gehen?

public MainForm() { 
    initComponents(); 
    connect = DbConnection.dbConnection(); 
    CreateResultSet(); 


} 

public void CreateResultSet(){ 
    try{ 

     stmt = connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE); 
     String sql = "select * from OAUTOPARTS_PRODUCT"; 
     stmt.executeQuery(sql); 
     rs = stmt.getResultSet(); 

    }catch(Exception e){ 

     JOptionPane.showMessageDialog(null, e); 
    } 

}