Java8如何使用lambda比较对象的属性

Comparator.comparing((Person p)->p.firstName)
          .thenComparing(p->p.lastName)
          .thenComparingInt(p->p.age);

或

Comparator.comparing(Person::getFirstName)
          .thenComparing(Person::getLastName)
          .thenComparingInt(Person::getAge);

或

// Person类实现Comparable接口

@Override
public int compareTo(Person o){
    return Comparator.comparing(Person::getFirstName)
              .thenComparing(Person::getLastName)
              .thenComparingInt(Person::getAge)
              .compare(this, o);
}