SWT combobox 联动菜单

import java.sql.DriverManager; import org.eclipse.swt.SWT; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; import org.eclipse.swt.widgets.Label; import org.eclipse.swt.widgets.Combo; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import org.eclipse.swt.events.SelectionAdapter; import org.eclipse.swt.events.SelectionEvent; public class DLC { protected Shell shell; /** * Launch the application. * @param args */ public static void main(String[] args) { try { DLC window = new DLC(); window.open(); } catch (Exception e) { e.printStackTrace(); } } /** * Open the window. */ public void open() { Display display = Display.getDefault(); createContents(); shell.open(); shell.layout(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) { display.sleep(); } } } /** * Create contents of the window. */ protected void createContents() { shell = new Shell(SWT.CLOSE); shell.setSize(336, 74); shell.setText("DLC-数据联动下拉框"); Label lblNewLabel = new Label(shell, SWT.NONE); lblNewLabel.setAlignment(SWT.RIGHT); lblNewLabel.setBounds(10, 10, 54, 12); lblNewLabel.setText("主要分类"); Label label = new Label(shell, SWT.NONE); label.setText("次要分类"); label.setAlignment(SWT.RIGHT); label.setBounds(173, 10, 54, 12); final Combo combo = new Combo(shell, SWT.READ_ONLY); combo.setBounds(70, 10, 87, 20); final Combo subcombo = new Combo(shell, SWT.READ_ONLY); subcombo.setBounds(233, 10, 87, 20); subcombo.setEnabled(false); try { Conn MySqlLink = new Conn(); MySqlLink.conn(); Connection connect = DriverManager.getConnection( "jdbc:mysql://localhost:3306/BuBuDB","root","123456"); Statement stmt = connect.createStatement(); ResultSet rs = stmt.executeQuery("select * from mcc order by id asc"); int i=0; while (rs.next()) { combo.add(rs.getString("MainClass"),i); i+=1; } combo.addSelectionListener(new SelectionAdapter() { @Override public void widgetSelected(SelectionEvent e) { try { subcombo.removeAll(); Conn aa = new Conn(); aa.conn(); Connection connect = DriverManager.getConnection( "jdbc:mysql://localhost:3306/BuBuDB","root","20050819"); Statement stmt = connect.createStatement(); ResultSet rs = stmt.executeQuery("select * from scc where MainClass='"+ combo.getText() +"' order by id asc"); int i=0; while (rs.next()) { subcombo.add(rs.getString("SubClass"),i); i+=1; } subcombo.setEnabled(true);} catch (SQLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } } }); } catch (Exception e) { System.out.print("get data error!"); e.printStackTrace(); } } }