package com.http;import java.awt.*;import java.awt.event.*;import javax.swing.*;public class SwingJTextComponent extends JFrame{    private static final int TEXTAREA_ROWS = 8;    private static final int TEXTARER_COLUMNS= 20;    public SwingJTextComponent()    {        //创建文本域实例        final JTextField textField = new JTextField();        final JPasswordField  passwordField = new JPasswordField();                //定义一个Panel,设置了表格布局管理器并指定行与列        JPanel northPanel = new JPanel();        northPanel.setLayout(new GridLayout(2,2));//        添加文本域的标签        northPanel.add(new JLabel("User name:", SwingConstants.RIGHT));//        将文本域添加到panel        northPanel.add(textField);        northPanel.add(new JLabel("Password:", SwingConstants.RIGHT));        northPanel.add(passwordField);//        将pannel添加到frame        add(northPanel,BorderLayout.NORTH);        //        定义文本区实例，并设置大小，添加到frame的中心位置        final JTextArea textArea = new JTextArea(TEXTAREA_ROWS,TEXTARER_COLUMNS);        JScrollPane scrollPane = new JScrollPane(textArea);        add(scrollPane, BorderLayout.CENTER);        //        定义一个按钮，添加到frame下方，并定义监听事件，点击按钮，文本区显示用户名与密码        JPanel southPanel = new JPanel();        JButton insertButton = new JButton("Insert");        insertButton.addActionListener(new ActionListener() {                        @Override            public void actionPerformed(ActionEvent e) {                // TODO Auto-generated method stub                textArea.append("User name:" + textField.getText() +                         " Password:" + new String(passwordField.getPassword()) + "\n");            }        });        southPanel.add(insertButton);        add(southPanel,BorderLayout.SOUTH);        pack();    }        public static void main(String[] argvs)    {        EventQueue.invokeLater(new Runnable()        {            public void run()            {                                JFrame frame = new SwingJTextComponent();                frame.setTitle("SwingJTextComponent");                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);                frame.setVisible(true);            }        });            }    }