java利用stream流查出符合某个条件的list，并且进行赋值

public class nullExcDemo {
    public static void main(String[] args) {
        List<Stu> list = new ArrayList<>();
        list.add(new Stu(19, "sire", 'n'));
        list.add(new Stu(23, "abc", 'm'));
        list.add(new Stu(19, "ab", 'm'));
        list.add(new Stu(null, "g", 'n'));
        // 筛选出符合条件的list 筛选出符合条件的list: [Stu(age=19, name=sire, sex=n), Stu(age=19, name=ab, sex=m)]
        List<Stu> filtered = list.stream().filter(s ->  s.getAge() != null && s.getAge()==19).collect(Collectors.<Stu>toList());
        System.out.println("筛选出符合条件的list: "+filtered);
        // 进行赋值 赋值后的结果：[Stu(age=null, name=sire, sex=n), Stu(age=null, name=ab, sex=m)]
        filtered.stream().forEach(o->o.setAge(null));
        System.out.println("赋值后的结果："+filtered);
    }
}
@Data
class Stu{
    private Integer age;
    private String name;
    private Character sex;

    public Stu(Integer age, String name, Character sex) {
        this.age = age;
        this.name = name;
        this.sex = sex;
    }
}

// 筛选出符合条件的list 筛选出符合条件的list: [Stu(age=19, name=sire, sex=n), Stu(age=19, name=ab, sex=m)]
List<Stu> filtered = list.stream().filter(s ->  s.getAge() != null && s.getAge()==19).collect(Collectors.<Stu>toList());
System.out.println("筛选出符合条件的list: "+filtered);
// 进行赋值 赋值后的结果：[Stu(age=null, name=sire, sex=n), Stu(age=null, name=ab, sex=m)]
filtered.stream().forEach(o->o.setAge(null));
System.out.println("赋值后的结果："+filtered);