1. Jackson:对象转Json
ObjectMapper mapper = new ObjectMapper();
//User类转JSON
String json = mapper.writeValueAsString(user);
2. Jackson:List转Json
List<User> list= new ArrayList<User>();
users.add(user);
// List转Json
String jsonlist = mapper.writeValueAsString(list);
3. Jackson:Json转对象
ObjectMapper mapper = new ObjectMapper();
// Json转对象
User user = mapper.readValue(json, User.class);
4. Jackson:Json转List
ObjectMapper mapper = new ObjectMapper();
//反序列化List
JavaType type = mapper.getTypeFactory().constructParametricType(List.class, User.class);
List<User> list = mapper.readValue(listJson,type);