Java重写equals和hashCode与泛型

问题描述

在一个java类中，我有以下代码：

   示例equals（）实现 Couple 可能类似于：
  @Override 
 public boolean equals（Object obj）{
 if（！（obj instanceof Couple））
 return假; 
 if（obj == this）
 return true; 
 
 Couple couple =（Couple）obj; 
 return（this.v1！= null&& this.v1.equals（couple.v1）
&& this.v2！= null&& this.v2.equals（ couple.v2））; 
} 
  
 
 
 和hashcode（）示例： 
 
 
  @Override 
 public int hashCode（）{
 final int prime = 31; 
 int result = 1; 
 result = prime * result +（（v1 == null）？0：v1.hashCode（））; 
 result = prime * result +（（v2 == null）？0：v2.hashCode（））; 
返回结果; 
} 
  
 
In a java class i have the following code:
private class Couple<V extends Comparable<V>>{

    private V v1;
    private V v2;

    public Couple(V v1, V v2){
        this.v1 = v1;
        this.v2 = v2;
    }
}
I use an HashMap and i want to use keys with the Couple type. For example if i want to insert a new element in the HashMap i do the following:
HashMap<Couple<V>, Integer> map = new HashMap<Couple<V>, Integer>();
map.put(new Couple<V>(v1, v2), new Integer(10));
How should i Override the equals and hashCode methods in the Couple class using Generics?
 解决方案 
Sample equals() implementation for Couple could be like:
@Override
public boolean equals(Object obj) {
   if (!(obj instanceof Couple))
        return false;
    if (obj == this)
        return true;

    Couple couple = (Couple) obj;
    return (this.v1 != null && this.v1.equals(couple.v1)
            && this.v2 != null && this.v2.equals(couple.v2));
}
And hashcode() example:
@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((v1 == null) ? 0 : v1.hashCode());
    result = prime * result + ((v2 == null) ? 0 : v2.hashCode());
    return result;
}
                        
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