list =和addAll在List＜实体类＞数组的应用

实体类 A

public class A {
    private String name;
    private Integer age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

用=会报错

    public static void main(String[] args) {
        List<A>[] lists=new ArrayList[4];
        List<A> list= new ArrayList<>();
        A a=new A();
        a.setName("小米");
        a.setAge(8);
        list.add(a);
         A a1=new A();
        a1.setName("小明");
        a1.setAge(8);
        list.add(a1);
         A a2=new A();
        a2.setName("小红");
        a2.setAge(8);
        list.add(a2);
         A a3=new A();
        a3.setName("小绿");
        a3.setAge(8);
        list.add(a3);
        for (int i = 0; i < list.size(); i++) {
            List<A> list1=list.subList(i,i+1);
            lists[i]=list1;

        }


    }

用 addAll就不报错

 public static void main(String[] args) {
        List<A>[] lists=new ArrayList[4];
        List<A> list= new ArrayList<>();
        A a=new A();
        a.setName("小米");
        a.setAge(8);
        list.add(a);
         A a1=new A();
        a1.setName("小明");
        a1.setAge(8);
        list.add(a1);
         A a2=new A();
        a2.setName("小红");
        a2.setAge(8);
        list.add(a2);
         A a3=new A();
        a3.setName("小绿");
        a3.setAge(8);
        list.add(a3);
        for (int i = 0; i < list.size(); i++) {
            List<A> alist=new ArrayList<>();
            List<A> list1=list.subList(i,i+1);
            alist.addAll(list1);
            lists[i]=alist;

        }


    }