/** 集合的添加元素和遍历 */ import java.util.*; class ArrayListTest { public static void main(String[] args) { System.out.println("Hello World!"); test1(); } public static void test1() { ArrayList al=new ArrayList(); al.add("zhangsan"); al.add("lisi"); al.add("wangwu"); al.add("zhangliu"); System.out.println(al.indexOf("lisi")); System.out.println("原始集合："+al); Iterator it=al.iterator(); while (it.hasNext()) { System.out.print(it.next()); } } }