src/main/java/wycc/util/ArrayUtils.java
public static int[] toIntArray(Collection<Integer> items) {
		int[] result = new int[items.size()];
		int i = 0;
		for (Integer v : items) {
			result[i++] = v;
		}
		return result;
	}
public static int[] toIntArray(Collection<Integer> items) {
		int[] result = new int[items.size()];
		int i = 0;
		for (Integer v : items) {
			result[i++] = v;
		}
		return result;
	}
Convert a collection of Integers into an int array.

@param items
@return