java-可变参数示例

package cd.itcast.day1;public class OrderItem {private Long id;private Double price;private Integer num;public OrderItem(Long id, Double price, Integer num) {super();this.id = id;this.price = price;this.num = num;}public Long getId() {return id;}public void setId(Long id) {this.id = id;}public Double getPrice() {return price;}public void setPrice(Double price) {this.price = price;}public Integer getNum() {return num;}public void setNum(Integer num) {this.num = num;}}package cd.itcast.day1;/** * 为了解决参数不固定性，引入了可变参数 *  * 类型 ... 引用名称 *  * @author Administrator *  */public class VarArgsDemo {public static void main(String[] args) {OrderItem item1 = new OrderItem(1l, 20d, 10);OrderItem item2 = new OrderItem(1l, 20d, 10);OrderItem item3 = new OrderItem(1l, 20d, 10);Double total = count(.8, new OrderItem[] { item1, item2, item3 });System.out.println(total);}/** * [Lcd.itcast.day1.OrderItem;@1fb8ee3 *  * @param items *            1,可变参数就是数组,在编译完成之后，方法的签名变成了数组的方式 2,可变参数必须放到参数列表的最后 * @return */private static Double count(Double cutoff, OrderItem... items) {// 在1.4写法：// Double total = new Double(0);// Double total=Double.valueOf(0);/** * 这里存在大量的自动装箱/拆箱特性，这个特性也是编译器级别的特性 */Double total = 0d;for (int i = 0; i < items.length; i++) {OrderItem item = items[i];total += item.getPrice() * item.getNum();}return total * cutoff;}private static Double sum(OrderItem[] items) {Double total = 0d;for (int i = 0; i < items.length; i++) {OrderItem item = items[i];total += item.getPrice() * item.getNum();}return total;}}