@Test
public void test05() {

    Map map = new LinkedHashMap<>();
    map.put(1, "12");
    map.put("2", 13);
    List list = new ArrayList();
    list.add("78");
    list.add(90);
    map.put(56, list);
    String src = DDRJSONUtils.toJSONString(map);
    Assert.equals(src, "{1:\"12\",\"2\":13,56:[\"78\",90]}");
}