<分区>
我正在处理一个示例，其中它使用 ArrayList 包含新实例并使用 Collections.sort() 方法使用可比较的接口(interface)。我不知道为什么它在排序时会打印出哈希码，也不知道我的代码中的错误在哪里。任何人都可以找出错误并详细解释我。
SortFruitObject.java
import java.util.*;
public class SortFruitObject{
public static void main(String[] args){
ArrayList<Fruit> frui = new ArrayList<Fruit>();
frui.add(new Fruit("Pine", "PineDesc", 500));
frui.add(new Fruit("Apple", "AppleDesc", 400));
frui.add(new Fruit("Banana", "BananaDesc", 450));
frui.add(new Fruit("JackFruit", "JackFruitDesc", 300));
Collections.sort(frui);
System.out.println(frui);
}
}
水果.java
import java.io.*;
import java.util.*;
public class Fruit implements Comparable<Fruit>{
private String fruitName;
private String fruitDesc;
private int fruitQuantity;
public int compareTo(Fruit f){
return fruitName.compareTo(f.getFruitName());
}
public Fruit(String fruitName, String fruitDesc, int fruitQuantity){
this.fruitName = fruitName;
this.fruitDesc = fruitDesc;
this.fruitQuantity = fruitQuantity;
}
public void setFruitName(String fruitName){
this.fruitName = fruitName;
}
public void setFruitDesc(String fruitDesc){
this.fruitDesc = fruitDesc;
}
public void setFruitQuantity(int fruitQuantity){
this.fruitQuantity = fruitQuantity;
}
public String getFruitName(){
return fruitName;
}
public String getFruitDesc(){
return fruitDesc;
}
public int getFruitQuantity(){
return fruitQuantity;
}
}
输出:
[Fruit@36422510, Fruit@308f5944, Fruit@132d9844, Fruit@1667a232]