Java-记事本程序、文件选择对话框（JFileChooser）

Bertha 。 2024-02-17 19:59 20阅读 0赞

基本的GUI基础和IO基础  
核心代码

JFileChooser jfc = new JFileChooser();
    jfc.setDialogTitle("另存为...");
    // jfc.showOpenDialog(null); // 显示打开文件对话框
    jfc.showSaveDialog(null); // 显示保存文件对话框
    jfc.setVisible(true);
    
    String filename = jfc.getSelectedFile().getAbsolutePath(); // 获取选择的文件的绝对路径

1 打开文件  
2 保存文件  
3 文件选择对话框

public class Base extends JFrame implements ActionListener{
        
    
    private static final long serialVersionUID = -1131829311416485951L;
    
    
    JTextArea jta = null;
    JMenuBar jmb = null;
    JMenu jm1 = null;
    JMenuItem jmi1 = null, jmi2 = null;
    
    public Base() {
        jta = new JTextArea();
    
        jmb = new JMenuBar();
        jm1 = new JMenu("文件");
        jm1.setMnemonic('F');
    
        jmi1 = new JMenuItem("打开");
        jmi2 = new JMenuItem("保存");
    
        jmi1.addActionListener(this);
        jmi1.setActionCommand("open");
        jmi2.addActionListener(this);
        jmi2.setActionCommand("save");
    
        this.setJMenuBar(jmb);
    
        jmb.add(jm1);
        jm1.add(jmi1);
        jm1.addSeparator();
        jm1.add(jmi2);
    
        this.add(jta);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(400, 300);
        this.setVisible(true);
    }
    
    //------------------------------------------------------
    public void actionPerformed(ActionEvent e) {
    
            if(e.getActionCommand().equals("open")) {
                // 文件选择窗口
                JFileChooser jfc1 = new JFileChooser();
                jfc1.setDialogTitle("请选择文件...");
    
                jfc1.showOpenDialog(null);
                jfc1.setVisible(true);
                // 得到用户选择的文件路径
                String filename = jfc1.getSelectedFile().getAbsolutePath();
    
    //          System.out.println(filename);
                BufferedReader br = null;
                try {
                    br = new BufferedReader(new FileReader(filename));
    
                    String s = "";
                    String allCon = "";
                    while((s=br.readLine())!=null) {
                        allCon+=s+"\r\n";
                    }
                    jta.setText(allCon);
                } catch (Exception e1) {
                    e1.printStackTrace();
                } finally {
                    try {
                        br.close();
                    } catch (IOException e1) {
                        e1.printStackTrace();
                    }
                }
    
    
            } else if(e.getActionCommand().equals("save")) {
                JFileChooser jfc2 = new JFileChooser();
                jfc2.setDialogTitle("另存为...");
                jfc2.showSaveDialog(null);
                jfc2.setVisible(true);
    
                String filename = jfc2.getSelectedFile().getAbsolutePath();
    
                BufferedWriter bw = null;
    
                try {
                    bw = new BufferedWriter(new FileWriter(filename));
    
                    bw.write(this.jta.getText());
    
                } catch (IOException e1) {
                    e1.printStackTrace();
                } finally {
                    try {
                        bw.close();
                    } catch (IOException e1) {
                        e1.printStackTrace();
                    }
                } 
            }
        }
    }