java中TreeMap排序的示例代码

TreeMap<Screen,Integer> res = new TreeMap<Screen, Integer>(new Comparator<Screen>() {
      @Override
      public int compare(Screen screen1, Screen t1) { // 定义TreeMap的排序方法
        return screen1.compareTo(t1); // TreeMap的排序方法是：调用screen的比较方法
      }
    });

public class Screen implements Comparable{
  private double size,price;
  
  ...
  
  @Override
  public int compareTo(Object s){ // 定义比较方法
    Screen screen = (Screen)s;
    return this.price>screen.getPrice()?-1:1; // 返回负整数和正整数
  }
}

import java.util.*;
import java.lang.Integer;

public class Screen implements Comparable{
  private double size,price;
  public Screen(){}
  public void setSize(double size){
    this.size = size;
  }
  public void setPrice(double price){
    this.price = price;
  }
  public double getSize(){ return this.size;}
  public double getPrice() { return this.price;}
  public void show(){
    System.out.println("size is: "+this.size+"; price is: "+this.price);
  }
  @Override
  public int compareTo(Object s){ // 定义比较方法
    Screen screen = (Screen)s;
    return this.price>screen.getPrice()?-1:1; // 返回负整数和正整数
  }
}

import java.util.Comparator;
import java.util.Scanner;
import java.util.TreeMap;
import problem2.Screen;

public class TestScreen {
  final static int MAX_NUM = 8;
  public static void main(String []args){
    TreeMap<Screen,Integer> res = new TreeMap<Screen, Integer>(new Comparator<Screen>() {
      @Override
      public int compare(Screen screen1, Screen t1) { // 定义TreeMap的排序方法
        return screen1.compareTo(t1); // TreeMap的排序方法是：调用screen的比较方法
      }
    });
    double price, size;
    Scanner scan = new Scanner(System.in);
    for(int i=0;i<MAX_NUM;++i){
      Screen screen = new Screen();
      size = scan.nextDouble();
      price = scan.nextDouble();
      screen.setSize(size);
      screen.setPrice(price);
      res.put(screen,i);
    }
    for(Screen screen:res.keySet()){
      screen.show();
    }
    return ;
  }
}
//    测试样例（输入）
//    1 2
//    3 4
//    5 6
//    7 8
//    9 10
//    1 2
//    3 4
//    3 4