用泛型，比較器排序時遇到的麻煩Map

Question

最初的目的是在HashMap中檢索一個按值排序的項目列表。

粗糙的代碼（名稱只是簡單）：

public abstract class Thing<T> implements Iface<T> { 
    private HashMap<T, Integer> map; 

    static class DescendingValueComparator<K, V extends Comparable<V>> implements Comparator<Map.Entry<K, V>> { 
     public int compare(Map.Entry<K,V> a, Map.Entry<K,V> b) { 
      return (b.getValue().compareTo(a.getValue())); 
     } 
    } 

    public LinkedHashMap<T, Integer> getSorted() { 
     LinkedHashMap<T, Integer> linked = new LinkedHashMap<T, Integer>(); 
     ArrayList<Map.Entry<T, Integer>> s = new ArrayList<Map.Entry<T, Integer>>(map.entrySet()); 

     Arrays.sort(s, new DescendingValueComparator<T, Integer>()); 
     //... 
     } 
} 

編譯器錯誤：

Thing.java:30: error: no suitable method found for sort(ArrayList<Entry<T#1,Integer>>,DescendingValueComparator<T#1,Integer>) 
     Arrays.sort(sorted, new DescendingValueComparator<T, Integer>()); 
      ^
    method Arrays.<T#2>sort(T#2[],int,int,Comparator<? super T#2>) is not applicable 
     (cannot instantiate from arguments because actual and formal argument lists differ in length) 
    method Arrays.<T#3>sort(T#3[],Comparator<? super T#3>) is not applicable 
     (no instance(s) of type variable(s) T#3 exist so that argument type ArrayList<Entry<T#1,Integer>> conforms to formal parameter type T#3[]) 
    method Arrays.sort(Object[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(Object[]) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(double[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(double[]) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(float[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(float[]) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(byte[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(byte[]) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(char[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(char[]) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(short[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(short[]) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(long[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(long[]) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(int[],int,int) is not applicable 
     (actual and formal argument lists differ in length) 
    method Arrays.sort(int[]) is not applicable 
     (actual and formal argument lists differ in length) 
    where T#1,T#2,T#3 are type-variables: 
    T#1 extends Object declared in class Thing 
    T#2 extends Object declared in method <T#2>sort(T#2[],int,int,Comparator<? super T#2>) 
    T#3 extends Object declared in method <T#3>sort(T#3[],Comparator<? super T#3>) 
1 error 

我大致能理解基本的仿製藥，但我發現通過之類的東西扔下位例如，T＃x。我盲目地試圖改變，似乎掀起了幾件事情，而不是像製作

new DescendingValueComparator<Map.Entry<T, Integer>>() 

，但我已經在這個一直盯着這麼久，沒有什麼有意義了。 （如果有人對泛型有很好的全面參考，我會很感激鏈接）。

感謝

Answer 1

你是一個ArrayList使用Arrays.sort。

Arrays.sort需要一個數組。

您應該改用Collections.sort。