javax.swing.filechooser.FileNameExtensionFilter#getExtensions ( )源码实例Demo

private void formPropertyChange(java.beans.PropertyChangeEvent evt) {//GEN-FIRST:event_formPropertyChange
  //Synchronize if the user selects a different filter
  if (evt.getPropertyName().equals(FILE_FILTER_CHANGED_PROPERTY)) {
    if (selectedFileName == null
        || (getSelectedFile() != null && selectedFileName.equals(getSelectedFile().getName()))) {
      return;
    }
    File file = new File(getCurrentDirectory(), selectedFileName);
    //We currently have no file selected so we dont need to modify it
    //The equals check ensures that both events wont trigger each other over and over
    Object filter = evt.getNewValue();
    if (filter instanceof FileNameExtensionFilter) {
      FileNameExtensionFilter extensionFilter = (FileNameExtensionFilter) filter;
      int fileExtensionIndex = getFileExtensionIndex(file);
      //Select the first extension of the filter as the new file extension
      String newExtension = extensionFilter.getExtensions()[0];
      //If the file has a known file ending, replace it. Else just add the new extension
      //at the end
      StringBuilder newPathBuilder = new StringBuilder();
      newPathBuilder.append(fileExtensionIndex >= 0
          ? file.getName().substring(0, fileExtensionIndex) : file.getName());
      if (!newPathBuilder.toString().endsWith(".")) {
        newPathBuilder.append(".");
      }
      newPathBuilder.append(newExtension);
      //Update the chosen file
      setSelectedFile(new File(file.getParent(), newPathBuilder.toString()));
    }
  }
  //Synchronize if the user selects a different file
  else if (evt.getPropertyName().equals(SELECTED_FILE_CHANGED_PROPERTY)) {
    Object newFile = evt.getNewValue();
    if (newFile instanceof File) {
      this.selectedFileName = ((File) newFile).getName();
    }
  }
}
 

/**
 * Returns the index of the file extension in the file name if the current file ending is
 * known by one of the file name extension filters.
 *
 * @param file The file
 * @return The index of a known file extension in the file's name or <code>-1</code>
 */
private int getFileExtensionIndex(File file) {
  for (FileFilter filter : getChoosableFileFilters()) {
    if (filter instanceof FileNameExtensionFilter) {
      FileNameExtensionFilter extensionFilter = (FileNameExtensionFilter) filter;
      for (String extension : extensionFilter.getExtensions()) {
        if (file.getName().endsWith(extension)) {
          return file.getName().length() - extension.length();
        }
      }
    }
  }
  return -1;
}
 

private String enforceExtension(String filePathName, JFileChooser ofd) {
	FileFilter fileExtFilter = ofd.getFileFilter();
	if (fileExtFilter == ofd.getAcceptAllFileFilter()) {
		return filePathName;
	}
	FileNameExtensionFilter fileNameExtensionFilter = (FileNameExtensionFilter) fileExtFilter;
	String ext = fileNameExtensionFilter.getExtensions()[0];
	if (!ext.equalsIgnoreCase(FilenameUtils.getExtension(filePathName))) {
		filePathName += "." + ext;
	}
	return filePathName;
}
 

private void onCompressFile(Compressor c) {
	File f = getSelectedArchiverFile(null);
	if (f == null) {
		return;
	}
	FileNameExtensionFilter filter = c.getFileFilter();
	String ext = "." + filter.getExtensions()[0];
	String destpath = f.getName() + ext;
	JFileChooser s = new JFileChooser(".");
	s.addChoosableFileFilter(filter);
	s.setSelectedFile(new File(destpath));
	int returnVal = s.showSaveDialog(this);
	if (returnVal != JFileChooser.APPROVE_OPTION) {
		return;
	}
	File ff = s.getSelectedFile();
	destpath = ff.getAbsolutePath();
	if (!filter.accept(ff)) {// 确保一定有后缀
		destpath += ext;
	}

	try {
		c.doCompress(f, destpath);
	} catch (IOException e) {
		e.printStackTrace();
	}
}
 

private void onArchiverFile(Archiver ma) {
	JFileChooser o = new JFileChooser(".");
	o.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
	o.setMultiSelectionEnabled(true);
	int returnVal = o.showOpenDialog(this);
	if (returnVal != JFileChooser.APPROVE_OPTION) {
		return;
	}
	File[] files = o.getSelectedFiles();

	JFileChooser s = new JFileChooser(".");
	FileNameExtensionFilter filter = ma.getFileFilter();
	s.addChoosableFileFilter(filter);
	returnVal = s.showSaveDialog(this);
	if (returnVal != JFileChooser.APPROVE_OPTION) {
		return;
	}
	File f = s.getSelectedFile();
	String filepath = f.getAbsolutePath();
	if (!filter.accept(f)) {// 确保一定有后缀
		filepath = filepath + "." + filter.getExtensions()[0];
	}

	try {
		ma.doArchiver(files, filepath);
	} catch (IOException e) {
		e.printStackTrace();
	}
}