Map循环遍历的常用方法

常用Map循环遍历的方法

  Map<String, Object> map = new HashMap<String, Object>();         map.put("1", "a");         map.put("2", "b");         map.put("3", "c");         System.out.println(map.containsKey("4"));          //构造测试数据         List<Map<String, Integer>> list = new ArrayList<>();          HashMap<String, Integer> map1 = new HashMap<String, Integer>() {             {                 put("a", 16);             }         };         list.add(map1);         HashMap<String, Integer> map2 = new HashMap<String, Integer>() {             {                 put("a", 17);             }         };         list.add(map2);         HashMap<String, Integer> map3 = new HashMap<String, Integer>() {             {                 put("a", 18);             }         };         list.add(map3);          Iterator<Map<String, Integer>> iterator = list.iterator();         while (iterator.hasNext()) {             Map<String, Integer> info = iterator.next();             if (Integer.valueOf(info.get("a").toString()) > 16) {                 iterator.remove();             }          }         for (Map<String, Integer> mapz : list) {             System.out.println(mapz.get("a"));         }          Map<String, Object> newmap = new HashMap<>();         newmap.put("1", "A");         newmap.put("2", "B");         newmap.put("3", "C"); 		//方法一         Set set = newmap.keySet();         Iterator iterator1 = set.iterator();         while (iterator1.hasNext()) {             Object next = iterator1.next();             System.out.println(next + "/" + newmap.get(next));         }  		//方法二         Set<Map.Entry<String, Object>> setx = newmap.entrySet();         Iterator<Map.Entry<String, Object>> iteratorx = setx.iterator();         while (iteratorx.hasNext()) {             Map.Entry<String, Object> mapx = iteratorx.next();             System.out.println(mapx.getKey() + "/" + mapx.getValue());         }          //方法三         Set<Map.Entry<String, Object>> entries = newmap.entrySet();         for (Map.Entry<String, Object> entry : entries) {            System.out.println(entry.getKey() + ",value为：" + entry.getValue());         }