public static void main(String[] args) {

         Map<String, Integer> map = new HashMap<String, Integer>();

         map.put("张三", 12);

         map.put("张三1", 121);

         map.put("张三2", 122);

         map.put("张三3", 123);

         map.put("张三4", 124);

         map.put("张三5", 125);

         map.put("张三6", 126);

         map.put("张三7", 127);

         // keySet

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

         Iterator<String> it = set.iterator();

         while (it.hasNext()) {

             String key = it.next();

             System.out.println(key + "---" + map.get(key));

         }

         System.out.println("==============================================");

         // foreach 遍历keySet

         for (String string : map.keySet()) {

             System.out.println(string + "===" + map.get(string));

         }

         System.out.println("==============================================");

         // entrySet

         Set<Entry<String, Integer>> setenty = map.entrySet();

         Iterator<Entry<String, Integer>> ite = setenty.iterator();

         while (ite.hasNext()) {

             Entry<String, Integer> m = ite.next();

             System.out.println(m.getKey() + "---" + m.getValue());

         }

         System.out.println("==============================================");

         // foreach 遍历entrySet

         for (Entry<String, Integer> entry : map.entrySet()) {

             System.out.println(entry.getKey() + "===" + entry.getValue());

         }

     }