Question

使用下面的代码，我可以移动到数据库的最后一条记录和数据库的第一条记录。我创建了next（）方法来移动到下一条记录。它从第一个记录移动到第二个记录，但它显示了这个错误（在最后一行之后设置了SQLException结果。我无法继续我的项目，直到我可以移动下一个和之前的记录。任何帮助请求

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

试试这个：

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);
    }

}

在您的类的构造函数中移动CreateResultSet()，这样只会创建一次。

我已经在私有方法中考虑了表单更新，该方法会在您的first，next和last方法中调用。

我有这个：CreateResultSet（）应该去哪里？

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);
    }

}

Java移动到下一个和上一个记录

1 个答案: