Java 将集合拆分为通用基类型的相同大小的较小部分

Question

我想将集合分成更小的分区。为此，我创建了以下方法:

/**
 * Splits collection into smaller collections of given size
 * @param c input collection
 * @param partitionSize partition maximum size
 * @return collection of collections
 */
private static Collection<Collection<MyClass>> splitCollection(Collection<MyClass> c, int partitionSize) {
  List<Collection<MyClass>> result = new ArrayList<>();
  List<MyClass> partition = new ArrayList<>();
  for (MyClass o : c) {
    if (partition.size() == partitionSize) {
      result.add(partition);
      partition = new ArrayList<>();
    }
    partition.add(o);
  }
  if (!partition.isEmpty()) {
    result.add(partition);
  }
  return result;
}

现在我想创建一个通用(独立于基本类型)函数，以便能够调用如下内容:

 List<Collection<MyClass>> result = splitCollection(myClassList, 500, MyClass.class);
 List<Collection<MyClass2>> result = splitCollection(myClass2List, 500, MyClass2.class);

但是如果我不想使用多态性(用对象替换我的类型)，我该如何实现这一点？

Answer 1

你想要做的是使用 Generics :

private static <T> Collection<Collection<T>> splitCollection(Collection<T> c, int partitionSize) {
    List<Collection<T>> result = new ArrayList<>();
    List<T> partition = new ArrayList<>();
    for (T o : c) {
        if (partition.size() == partitionSize) {
            result.add(partition);
            partition = new ArrayList<>();
        }
        partition.add(o);
    }
    if (!partition.isEmpty()) {
        result.add(partition);
    }
    return result;
}

然后你可以将其称为:

Collection<Collection<Integer>> lsts = splitCollection(Arrays.asList(1,2,3,4), 2);
Collection<Collection<String>> lsts = splitCollection(Arrays.asList("1","2","3","4"), 2);