一,实现Comparator接口可以实现比较大小
二,实现comparable接口实现对象是可比较的
Set<Book> set = new TreeSet<>(new Comparator<Book>() {
@Override
public int compare(Book o1, Book o2) {
return (int) (o1.getPrice() - o2.getPrice());
}
});//匿名内部类
public class Book implements Comparable<Book>{
public int compareTo(Book o) {//继承Comparable<>接口重写compareTo方法
return (int) (price - o.price);
}
}