使用字符串键实现自定义对象的Java二进制搜索

Question

我有课

class User{
   String territory;
   String company;
   String name;
}

Answer 1

您所需要的就是为User类实现可比接口。然后可以使用collections.binarysearch()方法（当然，只有在列表已排序的情况下）。

这样的事情对你来说很管用：

    public static void main(String[] args) {
        List <User> list = new ArrayList<>();
        list.add(new User("A1", "B1", "Name1"));
        list.add(new User("A2", "B2", "Name2"));
        list.add(new User("A3", "B3", "Name3"));
        list.add(new User("A4", "B4", "Name4"));
        list.add(new User("A5", "B5", "Name5"));

        System.out.println(list.get(Collections.binarySearch(list, new User("A4", "B4", "Name4"))));
    }


    static class User implements Comparable <User>{
        String territory;
        String company;
        String name;

        public User(String territory, String company, String name) {
            this.territory = territory;
            this.company = company;
            this.name = name;
        }

        @Override
        public int compareTo(User o) {
            return (territory+company).compareTo(o.territory+o.company);
        }

        @Override
        public String toString(){
            return territory + "," + company + "," + name;
        }
    }