Java如何使用Optional与Stream取代if判空逻辑（JDK8以上）

public class DemoUtils {

  public static void main(String[] args) {
    List<Person> personList = new ArrayList<>();
    personList.add(new Person());
    personList.add(null);
    personList.add(new Person("小明",10));
    personList.add(new Person("小红",12));
    
    for (Person person : personList) {
    //if判空逻辑
      if (person != null) {
        System.out.println(person.getName());
        System.out.println(person.getAge());
      }
    }
  }

  static class Person {
    private String name;
    private int age;

    public Person() {
    }

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

    public String getName() {
      return name;
    }
    public void setName(String name) {
      this.name = name;
    }
    public int getAge() {
      return age;
    }
    public void setAge(int age) {
      this.age = age;
    }
  }
}

 public static void main(String[] args) {
    List<Person> personList = new ArrayList<>();
    personList.add(new Person());
    personList.add(null);
    personList.add(new Person("小明",10));
    personList.add(new Person("小红",12));

    personList.stream().filter(Objects::nonNull).forEach(person->{
      System.out.println(person.getName());
      System.out.println(person.getAge());
    });
  }

public static void main(String[] args) {
  List<Person> personList = new ArrayList<>();
  personList.add(new Person());
  personList.add(null);
  personList.add(new Person("小明", 10));
  personList.add(new Person("小红", 12));

  Optional.ofNullable(personList).orElseGet(() -> {
    System.out.println("personList为null！");
    return new ArrayList<>();
  }).stream().filter(Objects::nonNull).forEach(person -> {
    System.out.println(person.getName());
    System.out.println(person.getAge());
  });
}

orElseGet(() -> {
  //代替log
  System.out.println("personList为null！");
  return new ArrayList<>();
})