java - 保存文件和另存为文件方法

Question

我正在使用 Netbeans 开发一个编辑器应用程序。我已经编写了使用 Jfilechooser 保存文件的代码，保存功能正常工作。但我在编写简单保存按钮的代码时遇到问题。 当前打开的选项卡的。给我一些想法来保存当前选项卡的内容，例如 ctrl+s 功能。这是我保存为方法的代码。提前致谢。

  private void saveAsmActionPerformed(java.awt.event.ActionEvent evt) {                                        
    // TODO add your handling code here:
  int returnVal = fileChooser.showSaveDialog(this);
  if (returnVal == fileChooser.APPROVE_OPTION) 
  {
    File dir1 = fileChooser.getCurrentDirectory();
    String dir = dir1.getPath();
    String name = fileChooser.getSelectedFile().getName();
    //if it dont have .txt at end of name then add it
    if (!name.endsWith(".txt"))
            {
                name = (name + ".txt");
            }    

    try{
    File file = new File(dir,name);
    int res = 0;

    if(file.exists())
    {
  res = JOptionPane.showConfirmDialog(null, "This file already exists, Overwrite it?");
    }
    if(res == 0)
    {

    FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);


     FilePanel selectedComp = (FilePanel)tabbedPane.getSelectedComponent();

        if (selectedComp != null) {
           String text = selectedComp.getTextArea().getText();
           bw.write(text);

        } else {
           System.out.println("No component selected");
        }

bw.close();
    tabbedPane.setTitleAt(tabbedPane.getSelectedIndex(), name);
     ClosableTab.apply(tabbedPane, tabbedPane.getTabCount()-1);
    }

    }
    catch(Exception e)
    {
        System.out.println("err");
    }

  }
  }    

Answer 1

执行“另存为”后，将文件存储为字段，然后“保存”写入现有文件。

public class FilePanel /* extends not sure */ {
    private File file;

    ...

    public File getFile() { return file; }
    public void setFile(File f) { file = f; }

    ...
}

/*
 * not sure how your event structure works
 * this is the common way to do it
 *
 * @Override
 * public void actionPerformed(ActionEvent evt) {
 *     if (evt.getSource() == saveAsButton) {
 *         saveAsAction();
 *     } else if (evt.getSource() == saveButton) {
 *         saveAction();
 *     }
 * }
 *
 */

// recommend refactor so "save" can call "save as" without regard to event
private void saveAsAction() {

    int exInput = JOptionPane.NO_OPTION;
    File file = null;

    // use a do-while and "no" to reshow the save dialog if exists

    do {
        int returnVal = fileChooser.showSaveDialog(null);

        if (returnVal != JFileChooser.APPROVE_OPTION) {
            return;
        }

        file = fileChooser.getSelectedFile();

        if (!file.getName().endsWith(".txt")) {
            file = new File(file.getParentFile(), file.getName() + ".txt");
        }

        if (file.exists()) {
            exInput = JOptionPane.showConfirmDialog(
                            null, "This file already exists, overwrite it?");

            if (exInput == JOptionPane.CANCEL_OPTION) {
                return;
            }
        }
    } while (file.exists() && exInput == JOptionPane.NO_OPTION);

    FilePanel selectedComp = (FilePanel)tabbedPane.getSelectedComponent();

    if (selectedComp != null) {
        String text = selectedComp.getTextArea().getText();
        file = writeToFile(file, text);
        selectedComp.setFile(file);

    } else {
        System.out.println("No component selected");
        return;
    }

    tabbedPane.setTitleAt(tabbedPane.getSelectedIndex(), file.getName());
    ClosableTab.apply(tabbedPane, tabbedPane.getTabCount() - 1);
}

private void saveAction() {

    FilePanel selectedComp = (FilePanel)tabbedPane.getSelectedComponent();

    if (selectedComp != null) {
        File file = selectedComp.getFile();

        if (file == null) {
            // imply no "save as" performed

            saveAsAction();
            return;
        }

        String text = selectedComp.getTextArea().getText();
        file = writeToFile(file, text);
        selectedComp.setFile(file);

    } else {
        System.out.println("No component selected");
    }
}

// recommend refactor so "save" and "save as" can share write code
private static File writeToFile(File file, String text) {

    try {

        FileWriter fw = new FileWriter(file);
        BufferedWriter bw = new BufferedWriter(fw);

        bw.write(text);
        bw.close();

        return file;

    } catch(Exception e) {
        // handle your IO errors better than this
        // files are not willy-nilly!

        System.out.println("err");
        return null;
    }
}