JComBox下拉框使用对象封装，显示时指定显示对象中的某一属性

public class Item {	private String id;	private String name;
public Item() {	}
public Item(String id, String name) {		this.id = id;		this.name = name;	}
public String getId() {		return id;	}
public void setId(String id) {		this.id = id;	}
public String getName() {		return name;	}
public void setName(String name) {		this.name = name;	}
// 重写toString方法，将内容显示在下拉框中	public String toString() {		return getName();	}}
public class JComboBoxModelTest extends JFrame {	JComboBox jc = new JComboBox();	JLabel jl = new JLabel("请选择证件:");		public JComboBoxModelTest() {		setTitle("在窗口中设置下拉列表框");		Item item = new Item();		item.setId("1");item.setName("aa");		jc.addItem(item);		item = new Item();		item.setId("2");item.setName("bb");		jc.addItem(item);		item = new Item();		item.setId("3");item.setName("cc");		//下拉框直接添加对象，显示时会直接调用Item的toString方法		jc.addItem(item);		setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);		Container cp = getContentPane();		cp.setLayout(new FlowLayout());		cp.add(jl);		cp.add(jc);
setSize(new Dimension(160, 180));		setVisible(true);	}		public static void main(String[] args) {		new JComboBoxModelTest();	}}