textareademo.java

来自「java课件 java课件 java课件 java课件」· Java 代码 · 共 62 行

//TextAreaDemo.java
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
public class TextAreaDemo extends JFrame implements ActionListener{
	private JButton jbtView = new JButton("View");
	private JTextField jtfFileName = new JTextField(20);
	private JTextArea jtaFile =new JTextArea();
	public TextAreaDemo(){
		JScrollPane jsp = new JScrollPane(jtaFile);
		JPanel p=new JPanel();
		p.setLayout(new BorderLayout());
		p.add(new JLabel("FileName"),BorderLayout.WEST);
		p.add(jtfFileName,BorderLayout.CENTER);
		p.add(jbtView,BorderLayout.EAST);
		jtfFileName.setBackground(Color.YELLOW);
		jtfFileName.setForeground(Color.RED);
		
		getContentPane().add(jsp,BorderLayout.CENTER);
		getContentPane().add(p,BorderLayout.SOUTH);
		
		jbtView.addActionListener(this);
		jtfFileName.addActionListener(this);
	}
	
	public void actionPerformed(ActionEvent e){
		if(e.getSource()==jbtView || e.getSource()==jtfFileName)
		   showFile();
	}
	
	private void showFile(){
		BufferedReader inFile=null;
		String fileName=jtfFileName.getText().trim();
		String inLine;
		try{
			inFile=new BufferedReader(new FileReader(fileName));
			while((inLine=inFile.readLine())!=null){
				jtaFile.append(inLine+'\n');
			}
		}catch(FileNotFoundException ex){
			jtfFileName.setText("File not found:"+fileName);
		}catch(IOException ex){
			System.out.println(ex.getMessage());
		}finally{
			try{
				if(inFile!=null)
				  inFile.close();
			}catch(IOException ex){
				System.out.println(ex.getMessage());
			}
		}
	}
	
	public static void main(String args[]){
		TextAreaDemo frame = new TextAreaDemo();
		frame.setTitle("Text Area Demo");
		frame.setSize(400,300);
		frame.setVisible(true);
	}
}