Vaadin-Grid的数字列不按数字排序

grid.setColumns("name", "age");

grid.getColumnByKey("age").setComparator((a, b) -> {
    if (a == null || b == null) {
        return 0;
    }
    return Integer.compare((Integer) a, (Integer) b);
});

grid.getColumnByKey("age").setComparator((a, b) -> {
    if (a == null || b == null) {
        return 0;
    }
    return Integer.compare((Integer) a, (Integer) b);
});

import com.vaadin.flow.component.grid.Grid;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.router.Route;

import java.util.ArrayList;
import java.util.List;

@Route("")
public class MainView extends VerticalLayout {

    public MainView() {
        Grid<Person> grid = new Grid<>(Person.class);
        grid.setColumns("name", "age");

        List<Person> persons = new ArrayList<>();
        persons.add(new Person("Alice", 30));
        persons.add(new Person("Bob", 25));
        persons.add(new Person("Charlie", 35));

        grid.setItems(persons);

        grid.getColumnByKey("age").setComparator((a, b) -> {
            if (a == null || b == null) {
                return 0;
            }
            return Integer.compare((Integer) a.getAge(), (Integer) b.getAge());
        });

        add(grid);
    }

    public static class Person {
        private String name;
        private Integer age;

        public Person(String name, Integer age) {
            this.name = name;
            this.age = age;
        }

        public String getName() {
            return name;
        }

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