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改进这个问题
我正在使用javaswing构建一个桌面应用程序，我已经连接了sqlite数据库并实现了服务类，但是我不知道如何调用这些方法并在应用程序中实现它们。
这是我创建的服务类之一，我已确认它们已成功连接到数据库

public class NumOfDaysService {

    private static Connection connection;
    private static PreparedStatement preparedStatement;
    private static Statement stmt;
    ResultSet resultSet;

    public void addNumberOfDays(WorkingDaysAndHoursModel work) {
        int numberOfDays = work.getNum_of_working_days();

        String sql = "INSERT INTO working_days_and_hours(num_of_working_days) VALUES('"+numberOfDays+"')";

      try {
            connection = SQLite_Connection.connect();
            preparedStatement = connection.prepareStatement(sql);
            boolean result = preparedStatement.execute();
            System.out.println("DB status: "+ result);
        } catch (Exception ex) {
            System.out.println(ex.toString());
            //Logger.getLogger(Services.class.getName()).log(Level.SEVERE, null, ex);
        }finally {      
                 // Services.colsedConnections();
        }  
    }

     public void select(){
        String sql = "SELECT num_of_working_days FROM working_days_and_hours";

         try {
            connection = SQLite_Connection.connect();
            stmt = connection.createStatement();
             resultSet = stmt.executeQuery(sql);
            System.out.println("DB status: "+ resultSet);
        } catch (Exception ex) {
            System.out.println(ex.toString());
            //Logger.getLogger(Services.class.getName()).log(Level.SEVERE, null, ex);
        }finally {      
                 // Services.colsedConnections();
        }  
    }

     public void update(int id, int num) {
        String sql = "UPDATE working_days_and_hours SET num_of_working_days = '"+num+"' WHERE id = '"+id+"'";

        try {
            connection = SQLite_Connection.connect();
            preparedStatement = connection.prepareStatement(sql);

            preparedStatement.setInt(1, id);
            preparedStatement.setInt(2, num);

            preparedStatement.executeUpdate();

            System.out.println("DB status: "+ preparedStatement);

        } catch (Exception ex) {
            System.out.println(ex.toString());
            //Logger.getLogger(Services.class.getName()).log(Level.SEVERE, null, ex);
        }finally {      
                 // Services.colsedConnections();
        }  
    }

     public void delete(int id) {
        String sql = "DELETE FROM working_days_and_hours WHERE id = ?";

        try {

            connection = SQLite_Connection.connect();
            preparedStatement = connection.prepareStatement(sql);

            // set the corresponding param
            preparedStatement.setInt(1, id);
            // execute the delete statement
            preparedStatement.executeUpdate();

        } catch (Exception ex) {
            System.out.println(ex.toString());
            //Logger.getLogger(Services.class.getName()).log(Level.SEVERE, null, ex);
        }finally {      
                 // Services.colsedConnections();
        }  
    }

//      public static void main(String[] args) {
//        NumOfDaysService lecturerService = new NumOfDaysService();
//        WorkingDaysAndHoursModel lecturer = new WorkingDaysAndHoursModel(3);
//        Lecturer lecturer2 = new Lecturer(0, "abcd", "123456", "eng", "OC", "Malabe", "new", "level", "rank");

//        lecturerService.addNumberOfDays(lecturer);
//        lecturerService.select();
//        lecturerService.delete(2);
//lecturerService.update(3, 2);

//    }

}

我的问题是，我想使用这些方法，但我不知道如何使用。
如何将insert方法调用为button方法，如何将select方法调用为文本字段？