package collection; import java.util.ArrayList; import java.util.Collection; import java.util.HashSet; import java.util.Iterator; public class CollectionTest03 { public static void main(String[] args) { // 创建集合对象 Collection c1 = new ArrayList();// 有序可重复 // 添加元素 c1.add(1); c1.add(2); c1.add(3); c1.add(4); c1.add(1); // 迭代集合 /*Iterator it = c1.iterator(); while (it.hasNext()){ Object obj = it.next(); System.out.println(obj); }*/ print(c1.iterator()); // 创建集合对象 Collection c2 = new HashSet();// 无序不重复 c2.add(100); c2.add(200); c2.add(300); c2.add(90); c2.add(400); c2.add(50); c2.add(60); c2.add(100); /*Iterator it2 = c2.iterator(); while (it2.hasNext()){ Object obj = it2.next(); System.out.println(obj); }*/ print(c2.iterator()); } public static void print(Iterator it){ while (it.hasNext()){ System.out.println(it.next()); } } }