Question

我有两个包含两种类型对象的数组列表。他们是两种类型的用户。我输入了一个id（两种类型的用户都有唯一的整数id），并想找出该用户是否存在于两个arraylist中。

ArrayList<Artist> artist = new ArrayList();
ArrayList<Customer> customer = new ArrayList();

class Artist implements User{
      private String name;
      private int a_id = 0;
      private ArrayList<ArrayList> albums = new ArrayList();
      private int money;
      private int ma = 999;
      private int mi = 100;

      public Artist(String name) {
          this.name = name;
          a_id = (int)(Math.random()*((ma - mi) + 1)) + mi;
      }
}
...<i>getters and setters</i>

class Customer implements User {
      private String name;
      private int subscription = 1;
      private int due = 0;
      private int c_id = 0;
      private int ma = 9999;
      private int mi = 1000;

      public Customer(String name) {
        this.name = name;
        c_id = (int) (Math.random() * ((ma - mi) + 1)) + mi;
      }
}
    ...<i>getters and setters</i>

Answer 1

使用anyMatch方法和||：

public boolean exist(ArrayList<Artist> artist, ArrayList<Customer> customer, int id) {
    return artist.stream().anyMatch(user -> user.getA_id() == id) ||
            customer.stream().anyMatch(user -> user.getC_id() == id);
}

Answer 2

您应该考虑只包含一个类型为User的列表，因为Artist和Customer属于user类型（它们都实现该接口）。
然后，您可以简单地使用流api来确定用户ID是否存在：

page2.html

在2个数组列表中搜索对象

2 个答案: