Question

我创建了几个对象，我想在ArrayList中只打印一个对象参数：

Superhero batman = new Superhero("Bruce", 26, "Batman");
Human rachel = new Human("Rachel", 24);

Superhero ironman = new Superhero("Tony", 35, "Ironman");
Human pepper = new Human("Pepper", 22);

List<Human> people = new ArrayList<Human>();
people.add(batman);
people.add(rachel);
people.add(ironman);
people.add(pepper);

我想打印：

Bruce
Rachel
Tony
Pepper

Answer 1

在Java 8之前

for (Human human : people) {
    System.out.println(human.getName());
}

从Java 8开始

people.stream().map(Human::getName).forEach(System.out::println);

Answer 2

for(Human human : people) {
    System.out.println(human.getName());
}

这应该为人员列表中的每个人打印名称。你应该在Human class中有方法：

getName() {
    return this.name;
}

打印ArrayList对象

2 个答案: