写道
HashMap map = new HashMap();
map.put("1", "Tom");
map.put("2", "Jim");
map.put("3", "Jane");
map.put("4", "Kevin");
map.put("6", "Bit");
map.put("2", "Gavin");
Set set =map.keySet();
//以数组的形式循环,特点是size瞬间确定
Object[] o =set.toArray();
for(int i=0;i<set.size();i++){
System.out.println("Loop One:"+o[i]);
}
//以链表的形式迭代,特点是size不固定
Iterator it= set.iterator() ;
while(it.hasNext()){
System.out.println("Loop Two:"+it.next()); ;
}
map.put("1", "Tom");
map.put("2", "Jim");
map.put("3", "Jane");
map.put("4", "Kevin");
map.put("6", "Bit");
map.put("2", "Gavin");
Set set =map.keySet();
//以数组的形式循环,特点是size瞬间确定
Object[] o =set.toArray();
for(int i=0;i<set.size();i++){
System.out.println("Loop One:"+o[i]);
}
//以链表的形式迭代,特点是size不固定
Iterator it= set.iterator() ;
while(it.hasNext()){
System.out.println("Loop Two:"+it.next()); ;
}