Example about copying multiple selected table cells to the clipboard. Select the cells and press CTRL+C. The clipboard data can then be pasted into Excel, Notepad, etc. Copy works, Paste operation will be added in a separate gist.

TableCopyCellsDemo.java

import javafx.application.Application;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.SelectionMode;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class TableCopyCellsDemo extends Application {

	private final ObservableList<Person> data = FXCollections.observableArrayList(new Person("Jacob", "Smith", 18), new Person("Isabella", "Johnson", 19), new Person("Ethan", "Williams", 20), new Person("Michael", "Brown", 21));

	public static void main(String[] args) {
		launch(args);
	}

	@Override
	public void start(Stage stage) {

		stage.setWidth(500);
		stage.setHeight(550);

		// create table columns
		TableColumn<Person, String> firstNameCol = new TableColumn<Person, String>("First Name");
		firstNameCol.setMinWidth(100);
		firstNameCol.setCellValueFactory(new PropertyValueFactory<Person, String>("firstName"));

		TableColumn<Person, String> lastNameCol = new TableColumn<Person, String>("Last Name");
		lastNameCol.setMinWidth(100);
		lastNameCol.setCellValueFactory(new PropertyValueFactory<Person, String>("lastName"));

		TableColumn<Person, Integer> ageCol = new TableColumn<Person, Integer>("Age");
		ageCol.setMinWidth(60);
		ageCol.setCellValueFactory(new PropertyValueFactory<Person, Integer>("age"));

		TableView<Person> table = new TableView<>();
		table.setPlaceholder(new Text("No content in table"));
		table.setItems(data);
		table.getColumns().addAll(firstNameCol, lastNameCol, ageCol);

		final VBox vbox = new VBox();
		vbox.setSpacing(5);
		vbox.setPadding(new Insets(10, 10, 10, 10));

		BorderPane borderPane = new BorderPane();
		borderPane.setCenter(table);

		vbox.getChildren().addAll(borderPane);

		vbox.getChildren().add( new Label( "Select cells and press CTRL+C. Paste the data into Excel or Notepad"));
		
		Scene scene = new Scene(vbox);

		stage.setScene(scene);
		stage.show();

		// enable multi-selection
		table.getSelectionModel().setCellSelectionEnabled(true);
		table.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);

		// enable copy/paste
		TableUtils.installCopyPasteHandler(table);
	}


	public static class Person {

		private final SimpleStringProperty firstName;
		private final SimpleStringProperty lastName;
		private final SimpleIntegerProperty age;

		private Person(String fName, String lName, Integer age) {
			this.firstName = new SimpleStringProperty(fName);
			this.lastName = new SimpleStringProperty(lName);
			this.age = new SimpleIntegerProperty(age);
		}

		public String getFirstName() {
			return firstName.get();
		}

		public void setFirstName(String fName) {
			firstName.set(fName);
		}

		public String getLastName() {
			return lastName.get();
		}

		public void setLastName(String fName) {
			lastName.set(fName);
		}

		public Integer getAge() {
			return age.get();
		}

		public void setAge(Integer fName) {
			age.set(fName);
		}
	}
	

}

TableUtils.java

import javafx.collections.ObservableList;
import javafx.event.EventHandler;
import javafx.scene.control.TablePosition;
import javafx.scene.control.TableView;
import javafx.scene.input.Clipboard;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyCodeCombination;
import javafx.scene.input.KeyCombination;
import javafx.scene.input.KeyEvent;

public class TableUtils {

	/**
	 * Install the keyboard handler:
	 *   + CTRL + C = copy to clipboard
	 * @param table
	 */
	public static void installCopyPasteHandler(TableView<?> table) {

		// install copy/paste keyboard handler
		table.setOnKeyPressed(new TableKeyEventHandler());

	}

	/**
	 * Copy/Paste keyboard event handler.
	 * The handler uses the keyEvent's source for the clipboard data. The source must be of type TableView.
	 */
	public static class TableKeyEventHandler implements EventHandler<KeyEvent> {

		KeyCodeCombination copyKeyCodeCompination = new KeyCodeCombination(KeyCode.C, KeyCombination.CONTROL_ANY);

		public void handle(final KeyEvent keyEvent) {

			if (copyKeyCodeCompination.match(keyEvent)) {

				if( keyEvent.getSource() instanceof TableView) {
				
					// copy to clipboard
					copySelectionToClipboard( (TableView<?>) keyEvent.getSource());
	
					System.out.println("Selection copied to clipboard");
	
					// event is handled, consume it
					keyEvent.consume();
					
				}

			}

		}

	}

	/**
	 * Get table selection and copy it to the clipboard.
	 * @param table
	 */
	public static void copySelectionToClipboard(TableView<?> table) {

		StringBuilder clipboardString = new StringBuilder();

		ObservableList<TablePosition> positionList = table.getSelectionModel().getSelectedCells();

		int prevRow = -1;

		for (TablePosition position : positionList) {

			int row = position.getRow();
			int col = position.getColumn();

			Object cell = (Object) table.getColumns().get(col).getCellData(row);

			// null-check: provide empty string for nulls
			if (cell == null) {
				cell = "";
			}

			// determine whether we advance in a row (tab) or a column
			// (newline).
			if (prevRow == row) {
				
				clipboardString.append('\t');
				
			} else if (prevRow != -1) {
				
				clipboardString.append('\n');
				
			}

			// create string from cell
			String text = cell.toString();

			// add new item to clipboard
			clipboardString.append(text);

			// remember previous
			prevRow = row;
		}

		// create clipboard content
		final ClipboardContent clipboardContent = new ClipboardContent();
		clipboardContent.putString(clipboardString.toString());

		// set clipboard content
		Clipboard.getSystemClipboard().setContent(clipboardContent);
	}
}