我开始用Java编写Java程序。 我遇到的问题是，当我尝试用sql中的表中的数据填充组合框时，它不起作用，我不知道为什么。
这是我到目前为止所尝试的内容：
public class Proveedores extends javax.swing.JFrame
{
Connection cnn;
ConexionesBaseDeDatos conexiones = new ConexionesBaseDeDatos();
public Proveedores() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jLabel5 = new javax.swing.JLabel();
txtNombreProveedor = new javax.swing.JTextField();
txtDireccionProveedor = new javax.swing.JTextField();
txtMailProveedor = new javax.swing.JTextField();
cmbProvinciasProveedores = new javax.swing.JComboBox();
btnCrearProveedor = new javax.swing.JButton();
btnModificarProveedor = new javax.swing.JButton();
btnDesabilitarProveedor = new javax.swing.JButton();
txtTelefonoProveedor = new javax.swing.JFormattedTextField();
jScrollPane1 = new javax.swing.JScrollPane();
listProveedores = new javax.swing.JList();
btnAceptar = new javax.swing.JButton();
btnGuardarCambios = new javax.swing.JButton();
btnDesabilitar = new javax.swing.JButton();
btnCancelar = new javax.swing.JButton();
jMenuBar1 = new javax.swing.JMenuBar();
jMenu1 = new javax.swing.JMenu();
jMenuItem1 = new javax.swing.JMenuItem();
jMenuItem2 = new javax.swing.JMenuItem();
jMenuItem3 = new javax.swing.JMenuItem();
jMenuItem4 = new javax.swing.JMenuItem();
jMenuItem5 = new javax.swing.JMenuItem();
jMenuItem6 = new javax.swing.JMenuItem();
jMenuItem7 = new javax.swing.JMenuItem();
jMenuItem10 = new javax.swing.JMenuItem();
jMenuItem11 = new javax.swing.JMenuItem();
jMenu3 = new javax.swing.JMenu();
jMenuItem9 = new javax.swing.JMenuItem();
jMenu4 = new javax.swing.JMenu();
jMenuItem8 = new javax.swing.JMenuItem();
jMenu2 = new javax.swing.JMenu();
jMenuItem12 = new javax.swing.JMenuItem();
jMenu5 = new javax.swing.JMenu();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
addWindowListener(new java.awt.event.WindowAdapter() {
public void windowActivated(java.awt.event.WindowEvent evt) {
formWindowActivated(evt);
}
});
jLabel1.setText("Nombre");
jLabel2.setText("Teléfono");
jLabel3.setText("Dirección");
jLabel4.setText("Mail");
jLabel5.setText("Provincia");
btnCrearProveedor.setText("Crear Proveedor");
btnModificarProveedor.setText("Modificar Proveedor");
btnDesabilitarProveedor.setText("Deshabilitar Proveedor");
txtTelefonoProveedor.setCursor(new java.awt.Cursor(java.awt.Cursor.TEXT_CURSOR));
listProveedores.setEnabled(false);
listProveedores.setVisibleRowCount(13);
jScrollPane1.setViewportView(listProveedores);
btnAceptar.setText("Aceptar");
btnGuardarCambios.setText("Guardar Cambios");
btnGuardarCambios.setEnabled(false);
btnDesabilitar.setText("Desabilitar");
btnDesabilitar.setEnabled(false);
btnCancelar.setText("Cancelar");
jMenu1.setText("File");
jMenuItem1.setText("Proveedores");
jMenu1.add(jMenuItem1);
jMenuItem2.setText("Clientes");
jMenu1.add(jMenuItem2);
jMenuItem3.setText("Modelos");
jMenu1.add(jMenuItem3);
jMenuItem4.setText("Eventos");
jMenu1.add(jMenuItem4);
jMenuItem5.setText("Subastas");
jMenu1.add(jMenuItem5);
jMenuItem6.setText("Compras");
jMenu1.add(jMenuItem6);
jMenuItem7.setText("Ventas");
jMenu1.add(jMenuItem7);
jMenuItem10.setText("Colecciones");
jMenu1.add(jMenuItem10);
jMenuItem11.setText("Lineas");
jMenu1.add(jMenuItem11);
jMenu3.setText("Productos");
jMenuItem9.setText("Tipos de productos");
jMenu3.add(jMenuItem9);
jMenu1.add(jMenu3);
jMenu4.setText("Insumos");
jMenuItem8.setText("Tipos de insumos");
jMenu4.add(jMenuItem8);
jMenu1.add(jMenu4);
jMenuBar1.add(jMenu1);
jMenu2.setText("Ayuda");
jMenuItem12.setText("Acerca de...");
jMenu2.add(jMenuItem12);
jMenuBar1.add(jMenu2);
jMenu5.setText("Salir");
jMenuBar1.add(jMenu5);
setJMenuBar(jMenuBar1);
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(40, 40, 40)
.addComponent(btnCrearProveedor)
.addGap(97, 97, 97)
.addComponent(btnModificarProveedor)
.addGap(104, 104, 104)
.addComponent(btnDesabilitarProveedor)
.addContainerGap(64, Short.MAX_VALUE))
.addGroup(layout.createSequentialGroup()
.addGap(67, 67, 67)
.addComponent(btnAceptar)
.addGap(52, 52, 52)
.addComponent(btnCancelar)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 92, Short.MAX_VALUE)
.addComponent(btnGuardarCambios)
.addGap(62, 62, 62)
.addComponent(btnDesabilitar)
.addGap(71, 71, 71))
.addGroup(layout.createSequentialGroup()
.addGap(22, 22, 22)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel5)
.addGap(18, 18, 18)
.addComponent(cmbProvinciasProveedores, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel2)
.addGap(18, 18, 18)
.addComponent(txtTelefonoProveedor))
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addComponent(jLabel4)
.addGap(42, 42, 42)
.addComponent(txtMailProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel3)
.addComponent(jLabel1))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(txtNombreProveedor)
.addComponent(txtDireccionProveedor, javax.swing.GroupLayout.DEFAULT_SIZE, 117, Short.MAX_VALUE))))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 137, Short.MAX_VALUE)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 312, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(36, 36, 36))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(20, 20, 20)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(btnCrearProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, 34, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(btnModificarProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, 34, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createSequentialGroup()
.addGap(1, 1, 1)
.addComponent(btnDesabilitarProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(50, 50, 50)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(txtNombreProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(27, 27, 27)
.addComponent(jLabel3))
.addGroup(layout.createSequentialGroup()
.addGap(22, 22, 22)
.addComponent(txtDireccionProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(20, 20, 20)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(3, 3, 3)
.addComponent(jLabel5))
.addComponent(cmbProvinciasProveedores, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(txtTelefonoProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(21, 21, 21)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(3, 3, 3)
.addComponent(jLabel4))
.addComponent(txtMailProveedor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(35, 35, 35))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(36, 36, 36)
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 223, Short.MAX_VALUE)
.addGap(27, 27, 27)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(btnDesabilitar)
.addComponent(btnAceptar)
.addComponent(btnCancelar)
.addComponent(btnGuardarCambios))
.addGap(64, 64, 64))
);
pack();
}// </editor-fold>
private void formWindowActivated(java.awt.event.WindowEvent evt) {
deshabilitarCampos();
if (conexiones.conectaralabase())
cargarComboProvincias();
}
public static void main()
{
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Proveedores().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton btnAceptar;
private javax.swing.JButton btnCancelar;
private javax.swing.JButton btnCrearProveedor;
private javax.swing.JButton btnDesabilitar;
private javax.swing.JButton btnDesabilitarProveedor;
private javax.swing.JButton btnGuardarCambios;
private javax.swing.JButton btnModificarProveedor;
private javax.swing.JComboBox cmbProvinciasProveedores;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JMenu jMenu1;
private javax.swing.JMenu jMenu2;
private javax.swing.JMenu jMenu3;
private javax.swing.JMenu jMenu4;
private javax.swing.JMenu jMenu5;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem jMenuItem1;
private javax.swing.JMenuItem jMenuItem10;
private javax.swing.JMenuItem jMenuItem11;
private javax.swing.JMenuItem jMenuItem12;
private javax.swing.JMenuItem jMenuItem2;
private javax.swing.JMenuItem jMenuItem3;
private javax.swing.JMenuItem jMenuItem4;
private javax.swing.JMenuItem jMenuItem5;
private javax.swing.JMenuItem jMenuItem6;
private javax.swing.JMenuItem jMenuItem7;
private javax.swing.JMenuItem jMenuItem8;
private javax.swing.JMenuItem jMenuItem9;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JList listProveedores;
private javax.swing.JTextField txtDireccionProveedor;
private javax.swing.JTextField txtMailProveedor;
private javax.swing.JTextField txtNombreProveedor;
private javax.swing.JFormattedTextField txtTelefonoProveedor;
// End of variables declaration
private void deshabilitarCampos()
{
txtNombreProveedor.setEnabled(false);
txtDireccionProveedor.setEnabled(false);
txtMailProveedor.setEnabled(false);
btnAceptar.setEnabled(false);
btnCancelar.setEnabled(false);
btnDesabilitar.setEnabled(false);
btnGuardarCambios.setEnabled(false);
cmbProvinciasProveedores.setEnabled(false);
listProveedores.setEnabled(false);
}
private void habilitarCamposBtnCrearProveedor()
{
btnAceptar.setEnabled(true);
btnCancelar.setEnabled(true);
cmbProvinciasProveedores.setEnabled(true);
listProveedores.setEnabled(true);
txtDireccionProveedor.setEnabled(true);
txtMailProveedor.setEnabled(true);
txtNombreProveedor.setEnabled(true);
}
private void habilitarCamposBtnModificarProveedor()
{
btnAceptar.setEnabled(false);
btnCancelar.setEnabled(true);
cmbProvinciasProveedores.setEnabled(true);
listProveedores.setEnabled(true);
txtDireccionProveedor.setEnabled(true);
txtMailProveedor.setEnabled(true);
txtNombreProveedor.setEnabled(true);
btnGuardarCambios.setEnabled(true);
btnDesabilitarProveedor.setEnabled(false);
btnDesabilitar.setEnabled(false);
btnCrearProveedor.setEnabled(false);
}
private void limpiarCampos()
{
cmbProvinciasProveedores.setSelectedIndex(-1);
txtDireccionProveedor.setText("");
txtMailProveedor.setText("");
txtNombreProveedor.setText("");
}
public void habilitarbtnCrearProveedor()
{
btnAceptar.setEnabled(true);
btnCancelar.setEnabled(true);
cmbProvinciasProveedores.setEnabled(true);
txtDireccionProveedor.setEnabled(true);
txtMailProveedor.setEnabled(true);
txtNombreProveedor.setEnabled(true);
txtTelefonoProveedor.setEnabled(true);
}
private void cargarComboProvincias()
{
Statement sql;
ResultSet datos;
boolean seguir;
Provincias provinciaActual;
try
{
sql = cnn.createStatement();
datos = sql.executeQuery("SELECT * FROM provincias WHERE id_provincia IS NOT NULL");
seguir = datos.next();
while (seguir)
{
provinciaActual = new Provincias();
provinciaActual.setNombre_provincia(datos.getString("nombre_provincia"));
provinciaActual.toString();
cmbProvinciasProveedores.addItem(provinciaActual);
seguir = datos.next();
}
}
catch (Exception e)
{
JOptionPane.showMessageDialog(null,e.getMessage() + "error en cargarComboProvincias");
e.printStackTrace();
}
}
}
and here is where i make the connection with the database:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.swing.JOptionPane;
public class ConexionesBaseDeDatos
{
Connection cnn;
public boolean conectaralabase()
{
String connString;
try
{
Class.forName ("com.microsoft.sqlserver.jdbc.SQLServerDriver");
connString = ("jdbc:sqlserver://GILLOPEZ:1433;database=DOLLS;Trusted_Connection=True");
cnn = DriverManager.getConnection (connString,"sa","1q2w3e4r");
}
catch(Exception e)
{
System.out.println( e.getMessage() + "Error en conectaralabase()");
return false;
}
return true;
}
}
感谢任何帮助。感谢。
答案 0 :(得分：3)
你必须在Resulset循环
1）将数据放入String[]数组
`String[] items = {"test1", "test2", "test3"};
JComboBox combo = new JComboBox(items);`
2）将数据放入Vector 1D Vector
Vector<String> v1 = new Vector<String>();
v1.add("item1");
v1.add("item2");
v1.add("item3");
JComboBox combo = new JComboBox(v1);
3）将数据放入ComboBoxModel
DefaultComboBoxModel model = new DefaultComboBoxModel();
model.add("item1");
model.add("item2");
model.add("item3");
JComboBox combo = new JComboBox();
combo.setModel(model);
但请在阅读之前阅读