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import java.io.File ;
import java.io.FileInputStream ;
import java.io.FileOutputStream ;
import java.io.PrintStream ;
import java.util.Scanner ;
import java.awt.BorderLayout ;
import java.awt.event.WindowAdapter ;
import java.awt.event.WindowEvent ;
import java.awt.event.ActionEvent ;
import java.awt.event.ActionListener ;
import javax.swing.JFrame  ;
import javax.swing.JTextArea ;
import javax.swing.JLabel ;
import javax.swing.JButton ;
import javax.swing.JPanel ;
import javax.swing.JFileChooser ;
import javax.swing.JScrollPane ;
class Note implements ActionListener{
    private JTextArea area = new JTextArea(8,10) ;  // 定义文本区
    private JFrame frame = new JFrame("Welcome To MLDN") ;
    private JButton open = new JButton("打开文件") ;
    private JButton save = new JButton("保存文件") ;
    private JLabel label = new JLabel("现在没有打开的文件") ;
    private JPanel butPan = new JPanel() ;
    public Note(){
        this.butPan.add(open) ; // 在面板中加入按钮
        this.butPan.add(save) ; // 在面板中加入按钮
        this.frame.setLayout(new BorderLayout(3,3)) ;
        this.frame.add(this.label,BorderLayout.NORTH) ;
        this.frame.add(this.butPan,BorderLayout.SOUTH) ;
        this.frame.add(new JScrollPane(this.area),BorderLayout.CENTER) ;
        this.frame.setSize(330,180) ;
        this.frame.setVisible(true) ;
        this.frame.addWindowListener(
            new WindowAdapter() {
                public void windowClosing(WindowEvent e){
                    System.exit(1) ;
                }
            }
        ) ;
        this.open.addActionListener(this) ;
        this.save.addActionListener(this) ;
    }
    public void actionPerformed(ActionEvent e){
        File file = null ;  // 接收文件
        int result = 0 ;    // 接收操作状态
        JFileChooser fileChooser = new JFileChooser() ; // 文件选择框
        if(e.getSource()==this.open){   // 表示执行的是打开操作
            this.area.setText("") ; // 打开将文字区域的内容清空
            fileChooser.setApproveButtonText("确定") ;
            fileChooser.setDialogTitle("打开文件") ;
            result = fileChooser.showOpenDialog(this.frame) ;
            if(result==JFileChooser.APPROVE_OPTION){    // 选择的是确定按钮
                file = fileChooser.getSelectedFile() ;  // 得到选择的文件
                this.label.setText("打开的文件名称为：" + file.getName()) ;
            }else if(result==JFileChooser.CANCEL_OPTION){
                this.label.setText("没有选择任何文件") ;
            }else{
                this.label.setText("操作出现错误") ;
            }
            if(file!=null){
                try{
                    Scanner scan = new Scanner(new FileInputStream(file)) ;
                    scan.useDelimiter("\n") ;
                    while(scan.hasNext()){
                        this.area.append(scan.next()) ;
                        this.area.append("\n") ;
                    }
                    scan.close() ;
                }catch(Exception e1){}
            }
        }
        if(e.getSource()==this.save){   // 判断是否是保存操作
            result = fileChooser.showSaveDialog(this.frame) ;   // 显示保存框
            if(result==JFileChooser.APPROVE_OPTION){    // 选择的是确定按钮
                file = fileChooser.getSelectedFile() ;  // 得到选择的文件
                this.label.setText("选择的存储文件名称为：" + file.getName()) ;
            }else if(result==JFileChooser.CANCEL_OPTION){
                this.label.setText("没有选择任何文件") ;
            }else{
                this.label.setText("操作出现错误") ;
            }
            if(file!=null){
                try{
                    PrintStream out = new PrintStream(new FileOutputStream(file)) ;
                    out.print(this.area.getText()) ;
                    out.close() ;
                }catch(Exception e1){}
            }
        }
    }
}
 
public class JFileChooserDemo{
    public static void main(String args[]){
        new Note() ;
    }
}