public static void main(String[] args) {  Map
     
       map = new HashMap
      
       ();  map.put("1", "value1");  map.put("2", "value2");  map.put("3", "value3");    //第一种：普遍使用，二次取值  System.out.println("通过Map.keySet遍历key和value：");  for (String key : map.keySet()) {   System.out.println("key= "+ key + " and value= " + map.get(key));  }    //第二种  System.out.println("通过Map.entrySet使用iterator遍历key和value：");  Iterator
       
        
         > it = map.entrySet().iterator();  while (it.hasNext()) {   Map.Entry
         
           entry = it.next();   System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());  }    //第三种：推荐，尤其是容量大时  System.out.println("通过Map.entrySet遍历key和value");  for (Map.Entry
          
            entry : map.entrySet()) { System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue()); } //第四种 System.out.println("通过Map.values()遍历所有的value，但不能遍历key"); for (String v : map.values()) { System.out.println("value= " + v); } }
          
         
        
       
      
     

转自：http://www.cnblogs.com/kristain/articles/2033566.html