遍历MAP

遍历MAP的key

Map<String,Integer> map = new HashMap<String,Integer>();
map.put:
//遍历key
Set<String> keySet = map.keySet();
for(String key : keySet){
     System.out.println(key);          
}

//遍历value
Collection<Integer> value = map.values();
Iterator<Integer> iterator = values.iterator();
while(iterator.hasNext()){
       System.out.println(iterator.next());      
}

//遍历key - value
Set<Map.Entry<String,Integer>> entrySet = map.entrySet();
Iterator<Map.Entry<String,Integer>> iterator = entrySet.iterator();
while(iterator.hasNext()){
       Map.Entry<String,Integer> entry = iterator.next();
        String key = entry.getKey();
        Integer  value = entry.getValue();
        System.out.println(key+"---->"+ value);  
}