//导入Java类
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;

public class Demo extends JFrame {public Demo(){setBounds(100,100,200,100);setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);Container c=getContentPane();c.setLayout(new FlowLayout());JPasswordField jf=new JPasswordField();jf.setColumns(15);//设置字符长度为15jf.setFont(new Font("隶书",Font.BOLD,20));jf.setEchoChar('*');//设置回显字符
jf.addActionListener(new AbstractAction() {//添加监听public void actionPerformed(ActionEvent e) {//添加监听的方法
              System.out.println(jf.getPassword());}});c.add(jf);setVisible(true);}
public static void main(String[] args){new Demo();}
}

public class Demo extends JFrame {public Demo(){setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);setBounds(100,100,200,250);Container c=getContentPane();c.setLayout(null);String item[]={"one","two","tree","four","five"};JList<String> jl=new JList<>(item);//创建列表模型  单独添加// DefaultListModel<String> model=new DefaultListModel<>();//       for(String temp:item){//foreach遍历//          model.addElement(temp);// }//      JList<String> jl=new JList<>();//      model.addElement("新增元素");//      jl.setModel(model);//列表框载入列表模型/*SINGLE_SELECTION：单选SINGLE_INTERVAL_SELECTION:只能选择相邻的两个元素MULTIPLE_INTERVAL_SELECTION:随意选择*/
//jl.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);//设置选择模式
  JScrollPane js=new JScrollPane(jl);//将列表框添加到滚动面板上js.setBounds(40,50,100,100);c.add(js);JButton btn=new JButton("可选择");btn.setBounds(40,160,100,20);btn.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {//获取列表框选择的所有元素java.util.List<String> values=jl.getSelectedValuesList();for(String temp:values){//foreach 遍历System.out.println(temp);}}});c.add(btn);setVisible(true);}public static void main(String[] args) {new Demo();}
}