如何检查Wicket Textfield中的空值？

TextField textField = new TextField("textField");

if (!textField.isEmpty()) {
    // do something
}

TextField textField = new TextField("textField");

if (textField.length() > 0) {
    // do something
}

TextField textField = new TextField("textField");

if (!textField.getText().matches("\\s*")) {
    // do something
}