JFileChooser dialog = new JFileChooser();
        dialog.setDialogTitle("Vyberte CSV soubor ke zpracování");
        dialog.setFileFilter(new FileNameExtensionFilter("CVS soubory", "csv"));
        if(dialog.showOpenDialog(this) == JFileChooser.APPROVE_OPTION){
            File file = dialog.getSelectedFile();
            if(file.exists() && file.canRead()){
                try (BufferedReader br = new BufferedReader(new FileReader(file))) {
                    String line;
                    double count = 0;
                    int pocet = 0;
                    while((line = br.readLine()) != null){
                        line = line.trim();
                        if(line.length() > 0){
                            String[] values = line.split(";");
                            for(String value : values){
                                double d;
                                try{
                                    d = Double.parseDouble(value.replace(",", "."));
                                    pocet++;
                                }catch(NumberFormatException ex){
                                    d = 0;
                                }
                                count += d;
                            }
                        }
                    }
                    JOptionPane.showMessageDialog(this, "Součet hodnot je " + count + "\nPrůměr " + (count/pocet));
                } catch (IOException ex) {
                    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }