如何使用列表项目中的属性找到Arraylist项目的索引

Question

//使用要约ID的特定事件索引的最佳方法是什么？
使用Core Java或使用（Guava/Commons Collection）的第三方库？

  public class Event{
        private String title;
        //other attributes
        private ArrayList<Offers> lOffers;
    }
    public class Offers{
        private Sring Id;
        private String offerName;
    }

    //Code
    List<PayPerViewTitles>  PayPerViewTitleList = someMethod();
/*
offerId -> Offers Object id property
**/
    private int findEventPositionByOfferId(List<Event> eventList, String offerId){
       // how to implement this method to find the Main Event using the 
       offer->id
    }

此对象用于映射服务器JSON响应，

Answer 1

您可以使用映射将ID保存为键，对象为值，然后使用列表，例如：

List<Student> students = new ArrayList<>();
    Student student0 = Student.builder().id(1).name("wentjiang").age(23).build();
    Student student1 = Student.builder().id(2).name("wentjiang2").age(232).build();
    Map<Integer,Student> map = new HashMap<>();
    map.put(student0.getId(),student0);
    map.put(student1.getId(),student1);
    students.add(student0);
    students.add(student1);
    Integer findId = 2;
    Student student = map.get(findId);
    int index = students.indexOf(student);
    System.out.println(index);