[英]Java HashSet still allow duplicates
我有一個名為Mountain的類,其中重寫了hashCode()和equals()方法以便在HashSet中使用,這樣我就不會重復。 但是無論如何,我一直在重復山峰運動。 我弄不懂我在搞什么。 代碼實現:
package Unidad16;
public class Mountain{
String Name;
int Heigh;
Mountain(String n,int h){
this.Name=n;
this.Heigh = h;
}
public void setName(String name){
this.Name=name;
}
public String getName(){
return this.Name;
}
public void setHeigh(int Heigh){
this.Heigh=Heigh;
}
public int getHeigh(){
return this.Heigh;
}
public String toString(){
return this.Name;
}
@Override
public boolean equals(Object aMountain){
if(!(aMountain instanceof Mountain)){
return false;
}
Mountain m = (Mountain) aMountain;
return this.Name.equals(m.getName());
}
@Override
public int hashCode(){
return this.Name.hashCode();
}
}
package Unidad16;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
public class MainCompara {
public static void main(String args[]){
List<Mountain> listaMontanas = new ArrayList<Mountain>();
listaMontanas.add(new Mountain("Loma Cabrera", 2000));
listaMontanas.add(new Mountain("Loma Cabrera", 2000));
listaMontanas.add(new Mountain("Pico Duarte", 2000));
listaMontanas.add(new Mountain("Pico Duarte", 2000));
listaMontanas.add(new Mountain("Pico Duarte", 2000));
listaMontanas.add(new Mountain("Pico Duarte", 2000));
listaMontanas.add(new Mountain("Montaña X", 3000));
listaMontanas.add(new Mountain("Montaña X", 3000));
//Collections.sort(listaMontanas);
System.out.println(listaMontanas);
System.out.println("**************************************************");
HashSet<Mountain> miSet = new HashSet<Mountain>();
miSet.addAll(listaMontanas);
System.out.println(listaMontanas);
}
}
這是問題所在(最后一行):
System.out.println(listaMontanas);
你的意思是:
System.out.println(miSet);
目前,您只是將列表打印兩次,而不是第二次設置。
進行此更改后,輸出為:
[Loma Cabrera, Loma Cabrera, Pico Duarte, Pico Duarte, Pico Duarte, Pico Duarte,
Montaña X, Montaña X]
**************************************************
[Loma Cabrera, Montaña X, Pico Duarte]
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