java怎样从txt文件中读内容显示到JTextArea中

//包你满意

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.HeadlessException;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.filechooser.FileFilter;

/**
* @author wsj
* @date 2010-5-27, 下午09:10:10
*/
public class JTextAreaTest extends JFrame implements ActionListener{
JTextArea area=new JTextArea(20, 50);
private JButton btn=new JButton("读取文件到JTextArea...");

public JTextAreaTest(String title) throws HeadlessException {
super(title);
setBounds(100,100,900,500);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
area.setFont(new Font("宋尘租瞎体", Font.PLAIN,16));
area.setForeground(Color.red);
add(new JScrollPane(area),BorderLayout.CENTER);
JPanel panel=new JPanel();
panel.add(btn);
btn.addActionListener(this);
add(panel,BorderLayout.SOUTH);
validate();
}

public static void main(String[] args) {
new JTextAreaTest("JTextArea测试");
}

@Override
public void actionPerformed(ActionEvent e) {
if(e.getSource()==btn){
new FileReadThread(this).start();//开启文型备件读取线程
}
}
}
/**
* 文件读取线程
*/
class FileReadThread extends Thread{
private JTextAreaTest test;

public FileReadThread(JTextAreaTest test) {
this.test = test;
}

@Override
public void run() {
JFileChooser chooser=new JFileChooser("d:/");
chooser.setFileFilter(new FileFilter() {//定义文件过滤器,仅显示文件派空夹和txt文本

@Override
public String getDescription() {
return null;
}

@Override
public boolean accept(File file) {
if(file.isDirectory()||file.getName().endsWith(".txt"))
return true;
return false;
}
});
int option=chooser.showOpenDialog(test);
if(option==JFileChooser.APPROVE_OPTION){
File selFile=chooser.getSelectedFile();
try {
BufferedReader reader=new BufferedReader(new InputStreamReader(new FileInputStream(selFile),"gbk"));
String line=null;
while ((line=reader.readLine())!=null) {
test.area.append(line+"\n");
Thread.sleep(30);//线程暂停,以看到读取过程效果
}
} catch (Exception e1) {
e1.printStackTrace();
}
JOptionPane.showMessageDialog(test, "读取完毕");
}

}

}

用IO字节流和字符流