String a = "[1,2]";
        JSONArray json = JSONArray.fromObject(a);


        if(json.size()>0){
            Object[] objects =  json.toArray();
            for(int i=0;i<objects.length;i++){
                int j = (int) objects[i];
                System.out.println(objects[i]) ;
                System.out.println("j=="+j);// 得到 每个对象中的属性值
            }
        }