高级UI组件之文件对话框

  在对话框的基础模式上添加JFileChooser。读取文件，显示在文字编辑框中。并可以保存编辑框中的内容，选择指定文件位置。

package Night;

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.JFileChooser;

import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.awt.event.ActionEvent;
import javax.swing.JTextArea;
import java.awt.GridLayout;

public class FileChooserDemo {

	private JFrame frame;

	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					FileChooserDemo window = new FileChooserDemo();
					window.frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

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

	/**
	 * Initialize the contents of the frame.
	 */
	private void initialize() {
		frame = new JFrame();
		frame.setBounds(100, 100, 553, 371);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		JLabel label = new JLabel("\u8BF7\u9009\u62E9\u6587\u4EF6\uFF1A");
		frame.getContentPane().add(label, BorderLayout.NORTH);
		
		JPanel panel = new JPanel();
		frame.getContentPane().add(panel, BorderLayout.CENTER);
		panel.setLayout(new GridLayout(0, 1, 0, 0));
		
		JTextArea textArea = new JTextArea();
		panel.add(textArea);
		
		JPanel panel_1 = new JPanel();
		frame.getContentPane().add(panel_1, BorderLayout.SOUTH);
		
		JButton btnNewButton = new JButton("打开");
		btnNewButton.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				JFileChooser jfc = new JFileChooser();
				int value = jfc.showOpenDialog(frame);
				if(value==JFileChooser.APPROVE_OPTION)//选择打开
				{
					File fileName = jfc.getSelectedFile();
					try {
						FileReader fread = new FileReader(fileName);
						char[] ch = new char[1024];
						int hasData=0;
						try {
							if((hasData=fread.read(ch))>=0) {
								textArea.append(new String(ch));
							}
							fread.close();
						} catch (IOException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
						
						
					} catch (FileNotFoundException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
					
				}
				
			}
		});
		panel_1.add(btnNewButton);
		
		JButton btnNewButton_1 = new JButton("保存");
		btnNewButton_1.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				JFileChooser jfc = new JFileChooser();
				int value = jfc.showOpenDialog(frame);
				if(value==JFileChooser.APPROVE_OPTION) {
				File filename = jfc.getSelectedFile();
				try {
					FileWriter fw = new FileWriter(filename);
					char[] ch = new char[1024];
					int hasData=0;
					fw.write(textArea.getText());
					fw.close();
					
					
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}}
		});
		panel_1.add(btnNewButton_1);
		
		JButton btnNewButton_2 = new JButton("清除");
		btnNewButton_2.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				textArea.setText("");
			}
		});
		panel_1.add(btnNewButton_2);
	}

}