Mengisi kotak kombo dengan data mysql

Pertanyaan Anda tidak terlalu jelas, tetapi inilah cara Anda mengisi kotak kombo dengan hasil yang diambil dari database:

// Create an array list to be filled with group names
ArrayList<String> groupNames = new ArrayList<String>();
String query = "SELECT group_name FROM customer ORDER BY group_name"; 
PreparedStatement stm = connection.prepareStatement(query); 

ResultSet rs = stm.executeQuery(query); 

while (rs.next()) { 
    String groupName = rs.getString("group_name"); 
    // add group names to the array list
    groupNames.add(groupName)
} 

rs.close(); 


// Populate the combo box
DefaultComboBoxModel model = new DefaultComboBoxModel(groupNames.toArray());
comboBox.setModel(model);