java List排序

2.1 新建 Comparator 比较器

List<Person> list = new ArrayList<Person>() {};
Collections.sort(list, new PersonComparator());


class PersonComparator implements Comparator<Person> {
    @Override
    public int compare(Person p1, Person p2) {
      return p2.getAge() - p1.getAge();
    }
}

2.2 匿名类比较器

      List<Person> list = new ArrayList<Person>() {{
            add(new Person(1, 30, "北京"));
            add(new Person(2, 20, "西安"));
            add(new Person(3, 40, "上海"));
        }};
        // 使用匿名比较器排序
        Collections.sort(list, new Comparator<Person>() {
            @Override
            public int compare(Person p1, Person p2) {
                return p2.getAge() - p1.getAge();
            }
        });

参考：https://blog.csdn.net/sinat_32849897/article/details/122098256

参考2：https://blog.csdn.net/ScholarTang/article/details/108686221（ArrayList集合排序方式总结）