题目：

https://blog.csdn.net/qq_55056705/article/details/124563498

 

自定义排序步骤：

1. 定义所需要的对象

2. 实现Comparable接口（可指定泛型）

3. 重写compareTo方法（传入的参数相当于compare(Object o1, Object o2)中的o2，如果是o1-o2为顺序排序，o2-o1则是倒序排序）

关键代码：

class People implements Comparable<People> {
    private Integer id;
    private String code;
    private Integer age;

    public People(Integer id, String code, Integer age) {
        this.id = id;
        this.code = code;
        this.age = age;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public Integer getAge() {
        return age;
    }

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


    
    @Override
    public int compareTo(People people) {
        if (people.getAge()!=this.getAge()){
            return people.getAge()-this.getAge();
        }else {
            return this.getId()-people.getId();
        }
    }
}