ArrayList(JSONArray)中contains怎么用？

contains是判断元素是否在动态数组中。用法如下

 @Test
    public  void test() {
        ArrayList arrayList = new ArrayList();
        arrayList.add("AAA");
        arrayList.add("BBB");
        arrayList.add("CCC");
        System.out.println(arrayList.contains("AAA"));
        System.out.println(arrayList.contains("DDD"));

    }

   @Test
    public void test2(){
        JSONArray jsonArray = new JSONArray();
        jsonArray.add(1);
        jsonArray.add(2);
        jsonArray.add(3);
        System.out.println(jsonArray.contains(2));
        System.out.println(jsonArray.contains(4));
    }