使用jackson的ObjectMapper json转object

json 转 List<User>

CollectionType collectionType = MAPPER.getTypeFactory().constructCollectionType(ArrayList.class, GroupUser.class);//the sieze of the list is dependon the str json length although the json content is not the POJO type maybeArrayList<GroupUser> groupUsers = MAPPER.readValue(res, collectionType);

json 转 数组

ArrayType arrayType = MAPPER.getTypeFactory().constructArrayType(User.class);User[] users = MAPPER.readValue(expected, arrayType);

json 转 boject

User user = MAPPER.readValue(expected, User.class);

Object 转json

     String test = MAPPER.writeValueAsString(users);