js前台直接map定义

js前台直接map定义

var map = {}; // Map map = new HashMap();

map[key] = value; // map.put(key, value);

var value = map[key]; // Object value = map.get(key);

var has = key in map; // boolean has = map.containsKey(key);

delete map[key]; // map.remove(key);

// 遍历  

for(key in map){  

    alert(key + map[key]);  

}  

var length  = Object.keys(map).length ;

 

以下是获得Map第几个键值的笨方法

public static void main(String[] args) {
        Map<String, String> map = new HashMap<String, String>();

        map.put("key1", "value1");

        map.put("key2", "value2");

        map.put("key3", "value3");

        Set<String> keySet = map.keySet();

        int i = map.size()-1;

Map<Integer, String> mapKey = new HashMap<Integer, String>();
        Map<Integer, String> mapValue = new HashMap<Integer, String>();
         for(java.util.Map.Entry<String, String> entry : map.entrySet()) {
//将原来MAP的VALUE放入新的MAP的VALUE里面
             mapKey.put(i, entry.getValue());
//将原来MAP的KEY放入新的MAP的VALUE 里面
             mapValue.put(i, entry.getKey());
             i--;
        
         }
    //打印KEY值

         System.out.println(mapKey.get(2));
    //打印VALUE值

         System.out.println(mapValue.get(0));

    }