有意思的代码：

1 循环取map里的value：eg: map {k1 : {k2:v2}}
input: map k1 , k2 output: v2

public static Object getValue(Map map, String... keys) {
      if (map == null) {
          return null;
      } else {
          for (int i = 0; i < keys.length - 1; ++i) {
              if (!map.containsKey(keys[i]) || map.get(keys[i]) == null || map.get(keys[i]) == JSONObject.NULL) {
                  return null;
              }
              map = (Map) map.get(keys[i]);
          }
          if (map.containsKey(keys[keys.length - 1]) && map.get(keys[keys.length - 1]) != null && map.get(keys[keys.length - 1]) != JSONObject.NULL) {
              return map.get(keys[keys.length - 1]);
          } else {
              return null;
          }
      }
  }```