package BasicAndDontKnow; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; public class Test1 extends Test{ public static void main(String[] args) { Test1 test1=new Test1(); test1.a("2"); final int a=9; Map map=new HashMap(); map.put(1, 1); map.put(2, 2); Iterator iterator=map.keySet().iterator(); while(iterator.hasNext()){ Integer integer=(Integer) iterator.next(); System.out.println("键:"+integer+" 值:"+map.get(integer)); } //动态数组 List arrayList=new ArrayList(); arrayList.add("12"); arrayList.add("23"); Iterator iterator2=arrayList.iterator(); while(iterator2.hasNext()){ System.out.println(iterator2.next()); } for(Iterator iterator3=arrayList.iterator();iterator3.hasNext();){ System.out.println(iterator3.next()); } } }