Jackson学习(2)

将java对象序列化到文件中

public void test() {
	ObjectMapper obj = new ObjectMapper();
	Car car = new Car("yellow", "renault");
	obj.writevalue(new File("target/car.json"),car);
}

将json转换为java对象
Car car = objectMapper.readValue(json, Car.class)

json转换为jsonNode

String json = "{ "color" : "Black", "type" : "FIAT" }";
JsonNode jsonNode= objectMapper.readTree(json);
String color = jsonNode.get("color").asText();

json数组字符串转换为java

String jsonCarArray = 
  "[{ "color" : "Black", "type" : "BMW" }, { "color" : "Red", "type" : "FIAT" }]";
List listCar = objectMapper.readValue(jsonCarArray, new TypeReference>(){});

json字符串转换为java map

String json = "{ "color" : "Black", "type" : "BMW" }";
Map map 
  = objectMapper.readValue(json, new TypeReference>(){});

JsonNode转换为ObjectNode

ObjectNode objectNode = (ObjectNode) jsonNode;