Map的迭代

 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());
         }
     }