下拉列表（JComboBox）
列表框（JList）

package jframe; import java.awt.BorderLayout; import java.awt.Container; import java.awt.Dimension; import javax.swing.*;  public class jframe extends JFrame{          /**      *       */     PRivate static final long serialVersionUID = 1L;          public jframe(){         this.setTITle("test");         Container con = this.getContentPane();         con.setLayout(new BorderLayout());                                                         String [] a = {"身份证","军人证","残疾证","护照","身份证","军人证","残疾证","护照"};                //定义字符串         JComboBox jcombo = new JComboBox(a);                                                //实例化下拉列表         JList jlist = new JList(a);                                                            //实例化列表框         //实例化JScrollPane面板         JScrollPane jp = new JScrollPane(jlist);         jp.setPreferredSize(new Dimension(100, 200));                        //设置JScrollPane大小       //实例化JPanel面板         JPanel jpp1 = new JPanel();         jpp1.add(jcombo);                  con.add(BorderLayout.EAST,jp);         con.add(BorderLayout.WEST,jpp1);         this.setVisible(true);         this.setBounds(50, 50, 300, 200);         this.setDefaultCloseoperation(DISPOSE_ON_CLOSE);            //设置关闭方式，可以选择多种关闭玄子选项     }     public static void main(String[] args) {         new jframe();     } }