lunes, 27 de octubre de 2014

Agregar, eliminar, modificar y listar en JTable en Netbeans usando base de datos








Este ejemplo muestra como hacer una conexion a a base de datos y hacer consultas como eliminar, agregar, modificar y listar los datos de la base de datos, usando componentes graficos como botones,campos de texto , jtable y labels,  Para mostrar la informacion se usan resultset, etc.y muchas otras cosas Espero y les sea de utilidad para los que quieren aprender mas como yop 




 AQUI ABAJO LES DEJO EL CODIGO UTILIZADO PARA EL PROYECTO, sigan las instrucciones de los 2 videos. esta facil de entender
package dba;
import java.sql.Connection;
import java.sql.DriverManager;
import javax.swing.JOptionPane;

public class Mysql {
private static String db="unalm";
private static String user="root";
private static String pass="aquitupassword";
private static String url="jdbc:mysql://localhost:3306/"+db;
private static Connection Conn;

public static Connection getConnection(){
    try{
        Class.forName("com.mysql.jdbc.Driver");
        Conn=DriverManager.getConnection(url, user, pass);

}catch(Exception e){
    JOptionPane.showMessageDialog(null,"Error"+e.getMessage());
}
    return Conn;
}


}

----------------------------------------------------------------------------------------------------------

package form;

import javax.swing.table.DefaultTableModel;
import dba.Mysql;
import java.sql.*;
import javax.swing.JOptionPane;

public class Cliente extends javax.swing.JFrame {
DefaultTableModel model;
Connection Conn;
Statement sent;

public Cliente() {
        initComponents();
        Conn=Mysql.getConnection();
        Deshabilitar();
        Llenar();
    }
void Deshabilitar(){
    txtNombre.setEditable(false);

    txtDireccion.setEditable(false);
    txtCorreo.setEditable(false);
    txtTelefono.setEditable(false);
}
void Limpiar(){
    txtNombre.setText("");
    txtDireccion.setText("");
    txtCorreo.setText("");
    txtTelefono.setText("");
}
void Habilitar(){
    txtNombre.setEditable(true);
    txtCorreo.setEditable(true);
    txtDireccion.setEditable(true);
    txtTelefono.setEditable(true);
    txtNombre.requestFocus();
}
void Llenar(){
    try{
        Conn=Mysql.getConnection();
        String [] titulos ={"Id","Nombre","Direccion", "Telefono", "Correo"};
        String sql="select * from contactos";
        model=new DefaultTableModel(null, titulos);
        sent=Conn.createStatement();
        ResultSet rs=sent.executeQuery(sql);

        String fila []= new String [5];

        while(rs.next()){
            fila [0]=rs.getString("id");
            fila [1]=rs.getString("nombre");
            fila [2]=rs.getString("direccion");
            fila [3]=rs.getString("telefono");
            fila [4]=rs.getString("correo");

            model.addRow(fila);

        }
jTable1.setModel(model);
       
    }catch(Exception e){
e.printStackTrace();
    }
}

private void btnEliminarActionPerformed(java.awt.event.ActionEvent evt) {                                           
try{
    int fila=jTable1.getSelectedRow();
    String sql="delete from contactos where id="+jTable1.getValueAt(fila,0);
    sent=Conn.createStatement();
    int n=sent.executeUpdate(sql);
    if(n>0){
        Llenar();
        JOptionPane.showMessageDialog(null, "datos eliminados");
        Limpiar();
    }
}catch(Exception e){
    JOptionPane.showMessageDialog(null, "error"+e.getMessage());
}
  }

  private void btnGuardarActionPerformed(java.awt.event.ActionEvent evt) {                                          
try{
    String sql="insert into contactos ( direccion ,nombre, telefono, correo)" +
           "Values (?,?,?,?) ";
PreparedStatement ps=Conn.prepareCall(sql);
ps.setString(1, txtNombre.getText());
ps.setString(2, txtDireccion.getText());
ps.setString(3, txtTelefono.getText());
ps.setString(4, txtCorreo.getText());


int n=ps.executeUpdate();
if(n>0)
JOptionPane.showMessageDialog(null, "datos guardados");
}catch(Exception e){
    JOptionPane.showMessageDialog(null, "error"+ e.getMessage());
}
Llenar();
Limpiar();
    }                                          

    private void btnNuevoActionPerformed(java.awt.event.ActionEvent evt) {                                        
Limpiar();
Habilitar();
        // TODO add your handling code here:
    }
  private void jTable1MouseClicked(java.awt.event.MouseEvent evt) {                                    
 if(evt.getButton()==1){
   try{
       Habilitar();
        int fila=jTable1.getSelectedRow();
        String sql="select * from contactos where id="+jTable1.getValueAt(fila,0);
        sent=Conn.createStatement();
        ResultSet rs=sent.executeQuery(sql);
        rs.next();
        txtNombre.setText(rs.getString("nombre"));
        txtDireccion.setText(rs.getString("direccion"));
        txtTelefono.setText(rs.getString("telefono"));
        txtCorreo.setText(rs.getString("correo"));

}catch(Exception e){
    e.printStackTrace();
}
    }
    }        

private void btnModificarActionPerformed(java.awt.event.ActionEvent evt) {                                            
try{
    String sql="Update contactos set nombre=?, direccion=?, telefono=?, correo=?"+
            "where id=?";
    int fila=jTable1.getSelectedRow();
    String dao=(String)jTable1.getValueAt(fila,0);
    PreparedStatement ps=Conn.prepareCall(sql);
    ps.setString(1,txtNombre.getText());
    ps.setString(2,txtDireccion.getText());
    ps.setString(3,txtTelefono.getText());
    ps.setString(4,txtCorreo.getText());//valor de campos de texto a pasar a
    //BasedeDatos

   ps.setString(5,dao);//la llamada sql se muestra en la tabla

    int n=ps.executeUpdate();
    if(n>0){
        Limpiar();
        Llenar();
        JOptionPane.showMessageDialog(null, "datos modificados");
       
    }
}catch (Exception e){
    JOptionPane.showMessageDialog(null, "error"+ e.getMessage());
}
        // TODO add your handling code here:
    }             

private void btnCerrarActionPerformed(java.awt.event.ActionEvent evt) {                                         
System.exit(0);
        // TODO add your handling code here:
    }

public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Cliente().setVisible(true);
            }
        });
    }
   private javax.swing.JButton btnCerrar;
    private javax.swing.JButton btnEliminar;
    private javax.swing.JButton btnGuardar;
    private javax.swing.JButton btnModificar;
    private javax.swing.JButton btnNuevo;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    private javax.swing.JTextField txtCorreo;
    private javax.swing.JTextField txtDireccion;
    private javax.swing.JTextField txtNombre;
    private javax.swing.JTextField txtTelefono;
    // End of variables declaration                  

}

Como crear campo de texto, una area de texto, boton y etquetas en un frame en java usando jcreator

Este ejemplo hecho en jcreator 





import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;

public class Formulario extends JFrame implements ActionListener{
JLabel etiNombre, etiApellido, etiEdad;
JTextField txtNombre, txtApellido, txtEdad;
JButton boton;
JTextArea area;
JPanel panel;


    public Formulario() {
    etiNombre = new JLabel("nombre");
    etiNombre.setBounds(10,20,80,20);

    etiApellido = new JLabel("Apellido");
    etiApellido.setBounds(10,50,80,20);

    etiEdad = new JLabel("Edad");
    etiEdad.setBounds(10,80,80,20);

    txtNombre = new JTextField();
    txtNombre.setBounds(100,20,80,20);

    txtApellido = new JTextField();
    txtApellido.setBounds(100,50,80,20);

    txtEdad = new JTextField();
    txtEdad.setBounds(100,80,80,20);

    boton = new JButton("Aceptar");
    boton.setBounds(200,20,80,20);
    boton.addActionListener(this);

    area = new JTextArea();
    area.setBounds(10,110,300,250);
     
    panel=new JPanel();
    panel.setLayout(null);
    panel.add(etiNombre);
    panel.add(etiApellido);
    panel.add(etiEdad);
    panel.add(txtNombre);
    panel.add(txtApellido);
    panel.add(txtEdad);
    panel.add(boton);
    panel.add(area);
 
    add(panel);
    setSize(500,500);
    setVisible(true);
    }

    public static void main (String[] args) {
Formulario p=new Formulario();
}
    public  void actionPerformed(ActionEvent e){
    if(e.getSource()==boton)
    capturar();
    }

    public void capturar(){
    area.setText("\nLos datos capturaadps son nombre"+txtNombre.getText()+
    "\napellido"+txtApellido.getText()
    +"\nedad"+txtEdad.getText());
    }
}

A continuacion se muestra la explicacion del codigo hecho en Netbeans


jueves, 23 de octubre de 2014

Hacer cálculos estadísticos: moda, mediana, varianza, media, desviación típica, cuartil










import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;

public class Probabilidad_Estadistica extends JFrame implements ActionListener{

                JPanel paneldatos, paneldatosarriba, paneldatosabajo, paneldatoscentro,paneldatoscentroi, paneldatoscentroc, paneldatoscentrod, panelcalculos;
                JLabel lbldato, lblmedia, lblmoda, lblmediana, lblcuartil1, lblcuartil3, lbldtipica, lblvarianza;
                JTextField txtdato, txtmedia, txtmoda, txtmediana, txtcuartil1, txtcuartil3, txtdtipica, txtvarianza;
                JButton btnagregar, btnup, btndown, btnquitar, btnlimpiar, btnordenar, btncalcular;
                JList lista;
                JScrollPane desliza;
                DefaultListModel modelo;
                Dimension d;
                              
                public Probabilidad_Estadistica(){
                               //Inicializando el JFRAME con los valores deseados
                               super("Probabilidad & Estadistica");
                               this.setLayout(new GridLayout(1,2,15,15));
                               this.setVisible(true);
                               this.setSize(1000,300);
                               this.setLocationRelativeTo(null);
                               this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                              
                               //Creando los paneles principales
                               paneldatos=new JPanel(new BorderLayout());
                               paneldatos.setBorder(new TitledBorder("Datos"));
                               panelcalculos=new JPanel(new GridLayout(7,2,10,10));
                               panelcalculos.setBorder(new TitledBorder("Calculos"));
                              
                               //Creando los paneles secundarios
                               paneldatosarriba=new JPanel(new FlowLayout());
                               paneldatosabajo=new JPanel(new FlowLayout());
                               paneldatoscentro=new JPanel(new FlowLayout());
                               paneldatoscentroi=new JPanel(new GridLayout(2,1,5,5));
                               paneldatoscentroc=new JPanel();
                               paneldatoscentrod=new JPanel(new GridLayout(2,1,5,5));
                              
                               //Agregando objetos a paneldatosarriba
                               lbldato=new JLabel("Dato");
                               txtdato=new JTextField(10);
                               btnagregar=new JButton("Agregar");
                               paneldatosarriba.add(lbldato);
                               paneldatosarriba.add(txtdato);
                               paneldatosarriba.add(btnagregar);
                              
                               //Agregando objetos a paneldatoscentro
                               btnup=new JButton("Arriba");
                               btndown=new JButton("Abajo");
                               paneldatoscentroi.add(btnup);
                               paneldatoscentroi.add(btndown);
                              
                               lista=new JList();
                               modelo=new DefaultListModel();
                               lista.setModel(modelo);
                               d=new Dimension(150,300);
                               lista.setPreferredSize(d);
                               desliza=new JScrollPane(lista);
                               paneldatoscentroc.add(desliza);
                              
                               btnquitar=new JButton("Quitar");
                               btnlimpiar=new JButton("Limpiar");
                               paneldatoscentrod.add(btnquitar);
                               paneldatoscentrod.add(btnlimpiar);
                              
                               //Agregando objetos a paneldatosabajo
                               btnordenar=new JButton("Ordenar");
                               btncalcular=new JButton("Calcular");
                               paneldatosabajo.add(btnordenar);
                               paneldatosabajo.add(btncalcular);
                              
                               //Agregando objetos a panelcalculos
                               lblmedia=new JLabel("Media");
                               lblmoda=new JLabel("Moda");
                               lblmediana=new JLabel("Mediana");
                                lblcuartil1=new JLabel("Cuartil 1");
                               lblcuartil3=new JLabel("Cuartil 3");
                               lbldtipica=new JLabel("Desviacion Tipica");
                               lblvarianza=new JLabel("Varianza");
                               txtmedia=new JTextField(15);
                               txtmoda=new JTextField(15);
                               txtmediana=new JTextField(15);
                                txtcuartil1=new JTextField(15);
                               txtcuartil3=new JTextField(15);
                               txtdtipica=new JTextField(15);
                               txtvarianza=new JTextField(15);
                               panelcalculos.add(lblmedia);
                               panelcalculos.add(txtmedia);
                               panelcalculos.add(lblmoda);
                               panelcalculos.add(txtmoda);
                               panelcalculos.add(lblmediana);
                               panelcalculos.add(txtmediana);
                               panelcalculos.add(lblcuartil1);
                               panelcalculos.add(txtcuartil1);
                               panelcalculos.add(lblcuartil3);
                               panelcalculos.add(txtcuartil3);
                               panelcalculos.add(lbldtipica);
                               panelcalculos.add(txtdtipica);
                               panelcalculos.add(lblvarianza);
                               panelcalculos.add(txtvarianza);
                                                                                             
                               //Agregando los paneles
                               paneldatoscentro.add(paneldatoscentroi, FlowLayout.LEFT);
                               paneldatoscentro.add(paneldatoscentroc, FlowLayout.CENTER);
                               paneldatoscentro.add(paneldatoscentrod, FlowLayout.RIGHT);
                               paneldatos.add(paneldatosarriba, BorderLayout.NORTH);
                               paneldatos.add(paneldatoscentro, BorderLayout.CENTER);
                               paneldatos.add(paneldatosabajo, BorderLayout.SOUTH);
                               this.add(paneldatos);
                               this.add(panelcalculos);
                              
                               //Agregando eventos
                               btnagregar.addActionListener(this);
                               btnquitar.addActionListener(this);
                               btnlimpiar.addActionListener(this);
                               btnup.addActionListener(this);
                               btndown.addActionListener(this);
                               btnordenar.addActionListener(this);
                               btncalcular.addActionListener(this);                     
                              
                }

                public void actionPerformed(ActionEvent e){
                               if(e.getActionCommand().equals(btnagregar.getText())){
                                               Agregarobjeto();
                               }
                               if(e.getActionCommand().equals(btnquitar.getText())){
                                               Quitar();
                               }
                               if(e.getActionCommand().equals(btnlimpiar.getText())){
                                               Limpiar();
                               }
                               if(e.getActionCommand().equals(btnup.getText())){
                                               Up();
                               }
                               if(e.getActionCommand().equals(btndown.getText())){
                                               Down();
                               }
                               if(e.getActionCommand().equals(btnordenar.getText())){
                                               Ordenar();
                               }
                               if(e.getActionCommand().equals(btncalcular.getText())){
                                               //Agregando la instancia de la clase Calcular, la cual realiza las operaciones
                                               Calcular totales=new Calcular();
                                               totales.Media();
                                               totales.Moda();
                                               totales.Mediana();
                                               totales.Cuartil1();
                                               totales.Cuartil3();
                                               totales.DesviacionTipica();
                                               totales.Varianza();
                               }
                }
               
                //METODOS PARA LOS BOTONES
                //Metodo Agregar: Agrega el dato del txtdato al JList
                public void Agregarobjeto(){
                               modelo.addElement(txtdato.getText());
                               txtdato.setText("");                     
                }
               
                //Metodo Quitar: Elimina el elemento seleccionado del JList
                public void Quitar(){
                               int seleccion;
                               seleccion=lista.getSelectedIndex();
                               modelo.removeElementAt(seleccion);
                }

                //Metodo Limpiar: Elimina todos los elementos del Jlist
                public void Limpiar(){
                               modelo.removeAllElements();
                               txtmedia.setText("");
                               txtmoda.setText("");
                               txtmediana.setText("");
                               txtcuartil1.setText("");
                               txtcuartil3.setText("");
                               txtdtipica.setText("");
                               txtvarianza.setText("");
                }
               
                //Metodo Up: Mueve el objeto seleccionado hacia arriba
                public void Up(){
                               int subir,bajar;
                               Object up, down;
                               subir=lista.getSelectedIndex()-1;
                               bajar=lista.getSelectedIndex();
                               if(subir<0){
                                               JOptionPane.showMessageDialog(this,"No se puede mover hacia arriba porque es el primer elemento","Atencion!!!",JOptionPane.INFORMATION_MESSAGE);
                               }else{
                               up=modelo.getElementAt(bajar);
                               down=modelo.getElementAt(subir);
                               modelo.setElementAt(up,subir);
                               modelo.setElementAt(down,bajar);
                               lista.setSelectedIndex(subir);
                               }
                }
               
                //Metodo Down: Mueve el objeto seleccionado hacia abajo
                public void Down(){
                               int subir, bajar;
                               Object up,down;
                               bajar=lista.getSelectedIndex()+1;
                               subir=lista.getSelectedIndex();

                               if(bajar==modelo.getSize()){
                                               JOptionPane.showMessageDialog(this,"No se puede mover hacia abajo porque es el ultimo elemento","Atencion!!!",JOptionPane.INFORMATION_MESSAGE);
                               }else{
                               down=modelo.getElementAt(subir);
                               up=modelo.getElementAt(bajar);
                               modelo.setElementAt(down,bajar);
                               modelo.setElementAt(up,subir);
                               lista.setSelectedIndex(bajar);
                               }
                }
               
                //Metodo Ordenar: Ordena de menor a mayor los datos del JList
                public void Ordenar(){
                        for(int i=0;i<modelo.getSize()-1;i++){
                                               for(int a=i+1;a<modelo.getSize();a++){
                                                               String objeto1=String.valueOf(modelo.getElementAt(i));
                                                       String objeto2=String.valueOf(modelo.getElementAt(a));
                                                       double p1=Double.parseDouble(objeto1);
                                                               double p2=Double.parseDouble(objeto2);
                                                                              if(p1>p2){
                                                                                              Object temporal;
                                                                                              temporal=modelo.getElementAt(a);
                                                                                              modelo.setElementAt(modelo.getElementAt(i),a);
                                                                                              modelo.setElementAt(temporal,i);       
                                                               }                             
                                               }
                               }
                }
               
                //Clase Calcular: Calcula los datos necesarios con los datos que estan en la JList
                class Calcular{
                               //Calcular la Media Aritmetica
                               public void Media(){
                                               double total=0;
                                               double resultado;
                                               Object vector[]=modelo.toArray();
                                               String cadena[]=new String[modelo.getSize()];
                                               double numeros[]=new double[modelo.getSize()];
                                               //Primer for para convertir de tipo Object a String
                                               for(int i=0;i<modelo.getSize();i++){
                                                               cadena[i]=String.valueOf(vector[i]);
                                               }
                                               //Segundo for para convertir de tipo String a double
                                               for(int b=0;b<cadena.length;b++){
                                                               numeros[b]=Double.parseDouble(cadena[b]);
                                               }
                                               //Tercer for para sumar los valores del vector;
                                               for(int c=0;c<numeros.length;c++){
                                                               total+=numeros[c];
                                               }
                                               resultado=total/numeros.length;
                                               txtmedia.setText(String.valueOf(resultado));                 
                               }

                               //Calcula la Moda, el valor que mas se repite
                               public void Moda(){
                                               int total=0;
                                               double nummoda;
                                               Object vector[]=modelo.toArray();
                                               String cadena[]=new String[modelo.getSize()];
                                               double numeros[]=new double[modelo.getSize()];
                                               //Primer for para convertir de tipo Object a String
                                               for(int i=0;i<modelo.getSize();i++){
                                                               cadena[i]=String.valueOf(vector[i]);
                                               }
                                               //Segundo for para convertir de tipo String a double
                                               for(int b=0;b<cadena.length;b++){
                                                               numeros[b]=Double.parseDouble(cadena[b]);
                                               }
                                               //Recorre el vector y si halla un valor igual al primero va aumentando en 1 el contador de veces
                                               for(int c=0;c<numeros.length;c++){
                                                               double numero=numeros[c];
                                                               int totalveces=0;
                                                               for(int d=0;d<numeros.length;d++){
                                                                              if(numero==numeros[d]){
                                                                                              totalveces++;
                                                                               }
                                                               }                                                            
                                                               if(totalveces>total){
                                                                                              total=totalveces;
                                                                                              txtmoda.setText("El numero "+String.valueOf(numero)+" Se Repite "+String.valueOf(total)+" Veces");
                                                               }
                                               }
                               }
                              
                               //Calcula la Mediana, el valor del centro de la lista de datos
                               public void Mediana(){
                                               Object vector[]=modelo.toArray();
                                               String cadena[]=new String[modelo.getSize()];
                                               double numeros[]=new double[modelo.getSize()];
                                               int posicion=0;
                                               int division=0;
                                               double mediana=0;
                                               //Primer for para convertir de tipo Object a String
                                               for(int i=0;i<modelo.getSize();i++){
                                                               cadena[i]=String.valueOf(vector[i]);
                                               }
                                               //Segundo for para convertir de tipo String a double
                                               for(int b=0;b<cadena.length;b++){
                                                               numeros[b]=Double.parseDouble(cadena[b]);
                                               }
                                              
                                               posicion=numeros.length%2;
                                               if(posicion==0){
                                                               division=numeros.length/2;
                                                               mediana=(numeros[division]+numeros[division+1])/2;
                                                               txtmediana.setText(""+String.valueOf(mediana));
                                               }
                                               if(posicion==1){
                                                               division=(numeros.length+1)/2;
                                                               txtmediana.setText(""+String.valueOf(numeros[division-1]));
                                               }
                               }
                              
                               //Metodo Cuartil 1
                               public void Cuartil1(){
                                               double cuartil=0.25*modelo.getSize();
                                               double residuo=cuartil%1;
                                               double total=0;
                                               if(residuo>0){
                                                               double entero=(cuartil/1)-(cuartil%1);
                                                               total=(entero+1)*2;
                                                               txtcuartil3.setText(String.valueOf(total));
                                               }
                                               if(residuo==0){
                                                               double entero=(cuartil/1)-(cuartil%1);                                
                                                               total=(entero+1)/2;
                                                               txtcuartil3.setText(String.valueOf(total));
                                               }
                               }
                              
                               //Metodo Cuartil 3
                               public void Cuartil3(){
                                               double cuartil=0.75*modelo.getSize();
                                               double residuo=cuartil%1;
                                               double total=0;
                                               if(residuo>0){
                                                               double entero=(cuartil/1)-(cuartil%1);
                                                               total=(entero+1)*2;
                                                               txtcuartil1.setText(String.valueOf(total));
                                               }
                                               if(residuo==0){
                                                               double entero=(cuartil/1)-(cuartil%1);                                
                                                               total=(entero+1)/2;
                                                               txtcuartil1.setText(String.valueOf(total));
                                               }
                               }
                              
                               //Metodo Desviacion Tipica
                               public void DesviacionTipica(){
                                               Object vector[]=modelo.toArray();
                                               String cadena[]=new String[modelo.getSize()];
                                               double numeros[]=new double[modelo.getSize()];
                                               double radical=0;
                                               double desviacion=0;
                                               double desviaciontotal=0;
                                               double total=0;
                                               //Primer for para convertir de tipo Object a String
                                               for(int i=0;i<modelo.getSize();i++){
                                                               cadena[i]=String.valueOf(vector[i]);
                                               }
                                               //Segundo for para convertir de tipo String a double
                                               for(int b=0;b<cadena.length;b++){
                                                               numeros[b]=Double.parseDouble(cadena[b]);
                                               }
                                              
                                               for(int c=0;c<numeros.length;c++){
                                                               radical=(Math.pow((numeros[0]-numeros.length),2))/numeros.length;
                                                               desviacion=Math.sqrt(radical);
                                                               desviaciontotal+=desviacion;
                                               }
                                               total=desviaciontotal/numeros.length;
                                               txtdtipica.setText(String.valueOf(total));
                               }
                              
                               //Metodo Varianza
                               public void Varianza(){
                                               Object vector[]=modelo.toArray();
                                               String cadena[]=new String[modelo.getSize()];
                                               double numeros[]=new double[modelo.getSize()];
                                               double radical=0;
                                               double desviacion=0;
                                               double desviaciontotal=0;
                                               double total=0;
                                               double var=0;
                                               //Primer for para convertir de tipo Object a String
                                               for(int i=0;i<modelo.getSize();i++){
                                                               cadena[i]=String.valueOf(vector[i]);
                                               }
                                               //Segundo for para convertir de tipo String a double
                                               for(int b=0;b<cadena.length;b++){
                                                               numeros[b]=Double.parseDouble(cadena[b]);
                                               }
                                              
                                               for(int c=0;c<numeros.length;c++){
                                                               radical=(Math.pow((numeros[0]-numeros.length),2))/numeros.length;
                                                               desviacion=Math.sqrt(radical);
                                                               desviaciontotal+=desviacion;
                                               }
                                               total=desviaciontotal/numeros.length;
                                               var=Math.sqrt(total);
                                               txtvarianza.setText(String.valueOf(var));
                                              
                               }
                              
                }//Fin de la clase Calcular
               
               
                                               public static void main(String []args){
                                                               new Probabilidad_Estadistica();
                                               }




}