Set<String> set = new HashSet<String>();
set.add("a");
set.add("b");
set.add("c");
JSONArray jsonArray = JSONArray.fromObject(set);
System.out.println("set转的jsonArray==>"+jsonArray);
Set<String> mySet =new HashSet<String>(JSONArray.toCollection(jsonArray));
System.out.println("json转set获取到元素==>"+mySet.iterator().next());
运行后输出结果
set转的jsonArray==>["a","b","c"]
json转set获取到元素==>a