TreeSet存入的顺序跟存储的顺序不同,但是存储是按照排序存储的,但是它知道如何对类进行排序,毕竟类是可以改变的。所以TreeSet对类进行排序需要重写接口Comparactor内的compare方法
public static void main(String[] args) {
Book b1 = new Book();
Book b2 = new Book();
b1.name = "name";
b1.price = 10;
b2.name = "name";
b2.price = 20;
Set<Book> set = new TreeSet(new Book());
set.add(b1);
set.add(b2);
for(Book b : set) {
System.out.println(b.name+"价格"+b.price);
}
}
运行结果
name2价格10
name1价格20
import java.util.Comparator;
public class Book implements Comparator{
String name;
int price;
@Override
public int compare(Object o1, Object o2) {
// TODO Auto-generated method stub
Book b1 = (Book)o1;
Book b2 = (Book)o2;
if(b1.price > b2.price) {
return 1;
}
else if(b1.price < b2.price) {
return -1;
}
return 0;
}