排序复杂类型

Question

我建造了一流的夫妇的ArrayList：

public class Couple<E,K> { 
    E first; K second; 

    Couple(E first, K second){ 
     this.first = first; 
     this.second = second; 
    } 
    public E getFirst(){ 
     return first; 
    } 
    public K getSecond(){ 
     return second; 
    } 
} 

而一个ArrayList<Couple<String, Integer>>

ArrayList<Couple<URL, Integer>> a = ArrayList<Couple<URL, Integer>>(); 
a=fillArray(); 

我想排序“A”由夫妇的第二个元素的值是一个整数。

Answer 1

做这样

您SimpleComparator

class SimpleComparator implements Comparator<Couple<URL, Integer>> { 
    public int compare(Couple<URL, Integer> a, Couple<URL, Integer> b) { 
     return a.second.compareTo(b.second); 
    } 
} 

您的排序

Collections.sort(a,new SimpleComparator()); // now a is sorted based on second value.  

Answer 2

a.sort(new Comparator<Couple<URL, Integer>>() { 
    public int compare(Couple<URL, Integer> a, Couple<URL, Integer> b) { 
     return a.second.compareTo(b.second); //assuming a.second is not null 
    } 
});