I'm creating a software in Java which should be able to register artists, Albums and Tracks as well.
Everything is connected to a MySQL DB, the software requires only artist name, I show you the methods I created. I'm sorry many of the names are in Spanish, but this
is for my school and I can't use too many english words. I think you can understand it
This is the class Conexión which makes the connection to the DB:
public class Conexion {
Connection conexion=null;
/*Conectamos a la Base de Datos*/
public Conexion(){
try{
Class.forName("com.mysql.jdbc.Driver");
conexion=DriverManager.getConnection("jdbc:mysql://localhost/chinook", "root", "");
}catch(Exception excepcion){
excepcion.printStackTrace();
}
}
/*Devolvemos la conexion*/
public Connection getConnection(){
return conexion;
}
/*Cerramos la conexión a la Base de Datos*/
public void desconectar(){
try{
conexion.close();
}catch(Exception excepcion){
excepcion.printStackTrace();
}
}
}
This is the class Coordinador, this class is used to make the union among different classes (following model MVC), I paste you the part from adding the artist, the others are just related to views:
public void addArtista(ArtistaVO artistaVO){
miLogica.validarRegistroArtista(artistaVO);
}
The class ArtistaVO where I create get and set of the artist:
public class ArtistaVO {
private int idArtista;
private String nombreArtista;
public int getIdArtista(){
return idArtista;
}
public void setIdArtista(int idArtista){
this.idArtista=idArtista;
}
public String getNombreArtista(){
return nombreArtista;
}
public void setNombreArtista(String nombreArtista){
this.nombreArtista=nombreArtista;
}
}
Method to register the artist:
public void addArtista(ArtistaVO artistaVO){
Conexion conexion=new Conexion();
try{
//Insertamos los datos del Artista
PreparedStatement sqlAddArtist=conexion.getConnection().prepareStatement("INSERT into artist values(?,?)");
ResultSet resultado=sqlAddArtist.executeQuery();
while(resultado.next()){
sqlAddArtist.setString(1, artistaVO.getNombreArtista());
sqlAddArtist.setInt(2, getMaxId()+1);
}
JOptionPane.showMessageDialog(null, "Se ha añadido exitosamente","Información",JOptionPane.INFORMATION_MESSAGE);
sqlAddArtist.close();
conexion.desconectar();
}catch(SQLException excepcion){
System.out.println(excepcion.getMessage());
JOptionPane.showMessageDialog(null,"No se registro", "Error", JOptionPane.ERROR_MESSAGE);
}
}
This method is used to create Artist ID:
public int getMaxId(){
int id=0;
Conexion conexion=new Conexion();
try{
Statement sqlMaxId=conexion.getConnection().createStatement();
ResultSet resultado=sqlMaxId.executeQuery("SELECT max(ArtistId) from artist");
if(resultado.next()){
id=resultado.getInt(0);
}
conexion.desconectar();
sqlMaxId.close();
}catch(SQLException excepcion){
System.out.println(excepcion.getMessage());
}
return id;
}
This belongs to the window which register the artist after clicking the button:
public void actionPerformed(ActionEvent evento) {
if(evento.getSource()==botonAñadir){
try{
ArtistaVO artistaVO=new ArtistaVO();
artistaVO.setNombreArtista(campoTextoArtista.getText());
miCoordinador.addArtista(artistaVO);
}catch(Exception excepcion){
JOptionPane.showMessageDialog(null, "Error al añadir Artista", "Error", JOptionPane.ERROR_MESSAGE);
}
}
}
The error I get is Error al añadir Artista (Error adding Artist), I don't know where the failure can be.
This is the exception I get:
java.lang.NullPointerException
at controlador.Coordinador.addArtista(Coordinador.java:108)
at vista.VistaArtistasAdd.actionPerformed(VistaArtistasAdd.java:70)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(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.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(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$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.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$1.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)
This is the method validarRegistroArtista:
public void validarRegistroArtista(ArtistaVO artistaVO){
ArtistaDAO artistaDAO;
if(artistaVO.getIdArtista()>=0){
artistaDAO=new ArtistaDAO();
artistaDAO.addArtista(artistaVO);
}else{
JOptionPane.showMessageDialog(null, "Debe de introducirse algún numero de ID", "Advertencia", JOptionPane.WARNING_MESSAGE);
}
}
