Java 除法运算：上取整、下取整和四舍五入方法

public static void main(String[] args) { double d1 = 17; double d2 = 3; double result = d1 / d2; /** * 四舍五入 */ int roundNum = (int) Math.round(result); /** * 向上取整 */ int ceilNum = (int) Math.ceil(result); /** * 向下取整 */ int floorNum = (int) Math.floor(result); System.out.println("除法商值：" + result); System.out.println("四舍五入：" + roundNum); System.out.println("向上取整：" + ceilNum); System.out.println("向下取整：" + floorNum); Integer[] arr = {1, 2, 3, 4, 5}; List<Integer> list = new ArrayList<Integer>(); double childNum = 22; double colorNum = 5; double num = childNum / colorNum; System.out.println(num); int ceilNum1 = (int) Math.ceil(num); System.out.println(ceilNum1); for (int i = 0; i < ceilNum1; i++) { Collections.addAll(list, arr); } System.out.println(list); }