Json、Gson、Jackson

Gson gson = new Gson();
String userJson = gson.toJson(userObject);

// str代表的是json字符串，Student.class代表的是你要转成的类型
Gson gson = new Gson();
Student student = gson.fromJson(str, Student.class);

Type type = new TypeToken>() {}.getType();
List userLists = new Gson().fromJson(json, type);

String json = new Gson().toJson(list);

ObjectMapper objectMapper = new ObjectMapper();
People peo = new People();
String jsonStr = objectMapper.writevalueAsString(peo);

ObjectMapper objectMapper = new ObjectMapper();
People peo = objectMapper.readValue(jsonStr, People.class);

ObjectMapper objectMapper = new ObjectMapper();
JavaType javaType = objectMapper.getTypeFactory().constructParametricType(List.class, People.class);
List list = objectMapper.readValue(jsonStr, javaType);