如何正确添加数组？

Question

我正在尝试将Integer数组添加到Set中,如下所示,

int[] arr = { 2, 6, 4 , 2, 3, 3, 1, 7 }; 
Set<Integer> set = new HashSet<Integer>(Arrays.asList(arr));

我收到一些错误,如下所示,

myTest.java:192: error: no suitable constructor found for HashSet(List<int[]>)
    Set<Integer> set = new HashSet<Integer>(Arrays.asList(arr));
                       ^
constructor HashSet.HashSet(Collection<? extends Integer>) is not applicable
  (argument mismatch; inferred type does not conform to upper bound(s)
      inferred: int[]
      upper bound(s): Integer,Object)
constructor HashSet.HashSet(int) is not applicable
  (argument mismatch; no instance(s) of type variable(s) T exist so that List<T> conforms to int)
 where T is a type-variable:
T extends Object declared in method <T>asList(T...)
Note: Some messages have been simplified; recompile with -Xdiags:verbose to        get full output
   1 error

其次,我也尝试如下并仍然得到错误,

int[] arr = { 2, 6, 4 , 2, 3, 3, 1, 7 }; 
Set<Integer> set = new HashSet<Integer>( );
Collections.addAll(set, arr);

如何正确地将一个Integer数组添加到Set中？谢谢.

Answer 1

您需要使用包装器类型 Arrays.asList(T...)

Integer[] arr = { 2, 6, 4, 2, 3, 3, 1, 7 };
Set<Integer> set = new HashSet<>(Arrays.asList(arr));

或手动添加元素

int[] arr = { 2, 6, 4, 2, 3, 3, 1, 7 };
Set<Integer> set = new HashSet<>();
for (int v : arr) {
    set.add(v);
}

最后,如果您需要保留广告订单,则可以使用LinkedHashSet.