So füllen Sie JComboBox von SqlServer

Question

Ich versuche, eine JComboBox aus Daten in SqlServer zu füllen. Ich verwende WindowBuilder, wenn das einen Unterschied macht. Dies ist der Code, den ich bisher habe. Ich bin sehr neu in Java, also habe ich keine Ahnung, was ich tun soll.

import java.awt.EventQueue; 
import java.awt.Font; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.sql.Connection; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import javax.swing.JButton; 
import javax.swing.JComboBox; 
import javax.swing.JFrame; 
import javax.swing.JLabel; 
import javax.swing.JOptionPane; 
import javax.swing.JTable; 

public class Customer extends JFrame{ 

private JFrame frame; 
private JTable table; 
private JTable tblInformation; 
private JTable tblHistory; 

/** 
* Launch the application. 
*/ 
public static void NewScreen() 
{ 
    EventQueue.invokeLater(new Runnable() { 
     public void run() { 
      try { 
       Customer window = new Customer(); 
       window.frame.setVisible(true); 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
     } 
    }); 
} 
/** 
* Create the application. 
*/ 
public Customer() { 
    initialize(); 
} 

/** 
* Initialize the contents of the frame. 
*/ 
private void initialize() { 
    frame = new JFrame(); 
    frame.setBounds(100, 100, 819, 656); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    frame.getContentPane().setLayout(null); 

    JComboBox comboBox = new JComboBox(); 
    comboBox.setBounds(372, 28, 152, 22); 
    frame.getContentPane().add(comboBox); 

    JLabel lblCustomer = new JLabel("Select customer"); 
    lblCustomer.setFont(new Font("Tahoma", Font.PLAIN, 16)); 
    lblCustomer.setBounds(245, 30, 121, 16); 
    frame.getContentPane().add(lblCustomer); 

    JLabel lblCustomerInformation = new JLabel("Information"); 
    lblCustomerInformation.setFont(new Font("Tahoma", Font.PLAIN, 16)); 
    lblCustomerInformation.setBounds(12, 74, 92, 16); 
    frame.getContentPane().add(lblCustomerInformation); 

    JLabel lblHistory = new JLabel("History"); 
    lblHistory.setFont(new Font("Tahoma", Font.PLAIN, 16)); 
    lblHistory.setBounds(12, 334, 56, 16); 
    frame.getContentPane().add(lblHistory); 

    JButton btnEdit = new JButton("Edit"); 
    btnEdit.setBounds(12, 569, 97, 25); 
    frame.getContentPane().add(btnEdit); 

    JButton btnExit = new JButton("Exit"); 
    btnExit.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) { 
      Welcome.main(null); 
     } 
    }); 
    btnExit.setBounds(690, 569, 97, 25); 
    frame.getContentPane().add(btnExit); 

    JButton btnAdd = new JButton("Add"); 
    btnAdd.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent arg0) 
     { 
      String custIDString, firstName, lastName, companyName, phoneNumber, street, city, state, zip; 
      int custID; 

      custIDString = JOptionPane.showInputDialog(null,"Enter customer ID", "Customer ID", JOptionPane.INFORMATION_MESSAGE); 
      custID = Integer.parseInt(custIDString); 

      firstName = JOptionPane.showInputDialog(null,"Enter first name", "First Name", JOptionPane.INFORMATION_MESSAGE); 
      lastName = JOptionPane.showInputDialog(null,"Enter last name", "Last Name", JOptionPane.INFORMATION_MESSAGE); 
      companyName = JOptionPane.showInputDialog(null,"Enter company name", "Company Name", JOptionPane.INFORMATION_MESSAGE); 
      phoneNumber = JOptionPane.showInputDialog(null,"Enter phone number (xxx-xxx-xxx)", "Phone Number", JOptionPane.INFORMATION_MESSAGE); 
      street = JOptionPane.showInputDialog(null,"Enter street", "Street", JOptionPane.INFORMATION_MESSAGE); 
      city = JOptionPane.showInputDialog(null,"Enter city", "City", JOptionPane.INFORMATION_MESSAGE); 
      state = JOptionPane.showInputDialog(null,"Enter state", "State", JOptionPane.INFORMATION_MESSAGE); 
      zip = JOptionPane.showInputDialog(null,"Enter zip", "Zip", JOptionPane.INFORMATION_MESSAGE); 
     } 


    }); 
    btnAdd.setBounds(235, 569, 97, 25); 
    frame.getContentPane().add(btnAdd); 

    table = new JTable(); 
    table.setBounds(257, 168, 137, -66); 
    frame.getContentPane().add(table); 

    tblInformation = new JTable(); 
    tblInformation.setBounds(12, 96, 422, 156); 
    frame.getContentPane().add(tblInformation); 

    tblHistory = new JTable(); 
    tblHistory.setBounds(12, 357, 422, 177); 
    frame.getContentPane().add(tblHistory); 

    JButton btnDelete = new JButton("Delete"); 
    btnDelete.setBounds(474, 569, 97, 25); 
    frame.getContentPane().add(btnDelete); 
} 
public class TestComboBox extends JComboBox 
{ 
    private Connection sqlCon; 
    private Statement st; 

    public TestComboBox() 
    { 
     super(); 

     initComponents(); 
    } 
    private void initComponents() 
    { 
     try 
     { 
      st = sqlCon.createStatement(); 
      loadComboBox(); 
     } 
     catch (SQLException sqle) 
     { 
      System.out.println(sqle); 
     } 
    } 
    public void loadComboBox() 
    { 
     this.removeAllItems(); 
     this.addItem("Please select"); 
     try 
     { 
      ResultSet rs = st.executeQuery("select FirstName, LastName from Customer"); 
      while (rs.next()) 
      { 
       this.addItem(rs.getString("FirstName") + "" + rs.getString("LastName")); 
      } 
     } 
     catch (SQLException sqle) 
     { 
      System.out.println(sqle); 
     } 
    } 

} 
} 

Answer 1

public void loadCombo(){ 
    Vector vec = new Vector(); 

     try { 
      resultset = //"resultst from database"; 
      while (resultset.next()) { 
       vec.add(resultset.getString("table column")); 
       } 
       yourCombo.setModel(new DefaultComboBoxModel(vec)); 
     } catch (Exception ex) { 
      ex.printStackTrace(); 
     } 

    } 

hier auch ein Beispiel, was im hier zu tun bekommt values von resultset die Werte in eine der vector innerhalb des comboboxvector dann im Putting Hinzufügen dieses versuchen.

Answer 2

Haben Sie in Klassen über das Überschreiben der toString-Methode gehört? Ich werde versuchen es zu erklären.

Wenn Sie eine Klasse mit dem Namen Kunden haben und Attribute für diese Klasse sind Vorname und Nachname (mit Getter und Setter), dann könnten Sie toString-Methode in Kunden Klasse wie folgt außer Kraft setzen:

@Override 
public String toString() { 
    return firstName; 
} 

Dann könnten Sie erstellen eine Klasse Beispiel, die eine DefaultComboBoxModel wie folgt zurückgibt:

public static DefaultComboBoxModel getCustomerModel() { 
    DefaultComboBoxModel model = new DefaultComboBoxModel(); 
    ResultSet rs = st.executeQuery("select FirstName, LastName from Customer"); 
    while (rs.next()) { 
     Customer c = new Customer(); 
     c.setFirstName(rs.getString("FirstName")); 
     c.setLastName(rs.getString("LastName")); 
     model.addElement(c); 
    } 
    return model; 
} 

gesetzt Schließlich Ihr Combobox Modell wie folgt aus:

myComboBox.setModel(Example.getCustomerModel()); 

So in MeineComboBox werden Sie nur den Vornamen des Kunden sehen und wenn Sie einen Kunden von MeineComboBox Objekt erhalten mögen, dann:

Customer c = (Customer) myComboBox.getSelectedItem(); 

Grüße.