大虾们帮我看看这个JPanel为什么显示出来
郁闷呀..运行程序以后Panel显示不出来,大家给我说说怎么改呀....


package com.swtdesigner;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class TestArea {

private JFrame frame;
public static final int DEFAULT_WIDTH = 300;
public static final int DEFAULT_HEIGHT = 300;

private JTextArea textArea;
private JScrollPane scrollPane;
private JPanel buttonPanel;
private JButton wrapButton;
/**
* Launch the application
* @param args
*/
public static void main(String args[]) {
try {

TestArea window = new TestArea();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}

}

/**
* Create the application
*/
public TestArea() {
initialize();
}

/**
* Initialize the contents of the frame
*/
private void initialize() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setTitle( "TextAreaTest ");
frame.setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

buttonPanel = new JPanel();
// buttonPanel.setBounds(200,200, 200, 200);

// add button to append text into the text area

JButton insertButton = new JButton( "Insert ");
buttonPanel.add(insertButton);
insertButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
textArea.append( "The quick brown fox jumps over the lazy dog. ");
}
});

// add button to turn line wrapping on and off

wrapButton = new JButton( "Wrap ");
buttonPanel.add(wrapButton);
wrapButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
boolean wrap = !textArea.getLineWrap();
textArea.setLineWrap(wrap);
scrollPane.revalidate();
wrapButton.setText(wrap ? "No Wrap " : "Wrap ");
}
});

frame.add(buttonPanel, BorderLayout.SOUTH);

// add a text area with scroll bars

textArea = new JTextArea(8, 40);
scrollPane = new JScrollPane(textArea);

frame.add(scrollPane, BorderLayout.CENTER);
}

}





[解决办法]
注意你的Frame

JFrame frame = new JFrame(); －－－》不用重新定义。直接frame=new JFrame();
它把属性里的frame屏蔽了