谷歌的Gson.jar:
//list转换为json
Gson gson = new Gson();
List<Person> persons = new ArrayList<Person>();
String str = gson.toJson(persons);
//json转换为list
Gson gson = new Gson();
List<Person> persons = gson.fromJson(str, new TypeToken<List<Person>>(){}.getType());
阿里的fastJson.jar：
//list转换为json
List<CustPhone> list = new ArrayList<CustPhone>();
String str=JSON.toJSON(list).toString();
//json转换为list
List<Person> list = new ArrayList<Person>();
list = JSONObject.parseArray(jasonArray, Person.class);
参考：
http://blog.csdn.net/demonliuhui/article/details/52949079
http://blog.csdn.net/qxs965266509/article/details/42774691
http://huyizizhen.iteye.com/blog/1453621
http://blog.csdn.net/u010797575/article/details/43304981
http://blog.csdn.net/paincupid/article/details/51221391