map 集合迭代

Map<Integer,String> test = new HashMap<Integer,String>();
test.put(1, "aaa");
test.put(2, "bbb");
test.put(3, "ccc");
test.put(4, "ddd");
Iterator it =test.entrySet().iterator();
while(it.hasNext()){   
  Map.Entry<Integer,String> helloEntry =(Map.Entry<Integer,String>)
it.next();
  System.out.println( helloEntry.getKey()+"-----"+helloEntry.getValue()); } 
for(Map.Entry<Integer,String> m : test.entrySet()){
    System.out.println(m.getKey()+"----"+m.getValue());
}       
  Iterator<Integer> it = test.keySet().iterator();
while(it.hasNext()){   
int key = it.next();  
  System.out.println(key+"--keyset--"+test.get(key)); }
for(Object m :test.keySet()){   
int key = (int) m;    
System.out.println(m+"--nadaoduixiang--"+test.get(m));
}

描述：map集合