驗(yàn)證部分出現(xiàn)問(wèn)題，沒(méi)有關(guān)于空字段的消息顯示。立即提供幫助private void addbtnActionPerformed(java.awt.event.ActionEvent evt) {    try{    Class.forName("com.mysql.cj.jdbc.Driver");    Connection con =DriverManager.getConnection("jdbc:mysql://localhost:3306/dbfinance","root","1234");    String sql="insert into util(type_,due_date,month_,amount,units,status_) values(?,?,?,?,?,?)";    PreparedStatement pstm =con.prepareStatement(sql);    pstm.setString(1,electype.getSelectedItem().toString());    pstm.setString(2,date.getText().toString());    pstm.setString(3,jComboBox1.getSelectedItem().toString());    pstm.setDouble(4,Double.parseDouble(amount.getText()));    pstm.setString(5,unit.getText());    pstm.setString(6,status.getText());   pstm.executeUpdate();   JOptionPane.showMessageDialog(null, "success");   con.close();        }catch(Exception e){            JOptionPane.showMessageDialog(null,e);        }     if(amount.getText().isEmpty()||unit.getText().isEmpty()||status.getText().isEmpty()){            JOptionPane.showMessageDialog(null,"please enter data");           // errorname2.setText("fill this field");    }        }