jackson object to json string code example
Example 1: java json serializer
public class someClass {
ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addSerializer(MyAwesomeClass.class, new MyAwesomeSerializer());
mapper.registerModule(module);
jsonNode = mapper.convertValue(myAwesomeObject, JsonNode.class);
}
public class MyAwesomeSerializer extends StdSerializer<MyAwesomeClass> {
public MyAwesomeSerializer() {
super(MyAwesomeClass.class);
}
@Override
public void serialize(MyAwesomeClass myAwesomeClass, JsonGenerator jgen, SerializerProvider provider) throws IOException {
ObjectMapper mapper = new ObjectMapper();
jgen.writeStartObject();
jgen.writeStringField("name", myAwesomeClass.getName());
jgen.writeStringField("age", myAwesomeClass.getAge());
jgen.writeArrayFieldStart("hobbies");
for (Hobby hobby : myAwesomeClass.getHobbies()) {
jgen.writeObject(mapper.convertValue(hobby, JsonNode.class));
}
jgen.writeEndArray();
jgen.writeEndObject();
}
}
Example 2: convert json to object jackson
ObjectMapper objectMapper = new ObjectMapper();
String carJson =
"{ \"brand\" : \"Mercedes\", \"doors\" : 5 }";
try {
Car car = objectMapper.readValue(carJson, Car.class);
System.out.println("car brand = " + car.getBrand());
System.out.println("car doors = " + car.getDoors());
} catch (IOException e) {
e.printStackTrace();
}
Example 3: jackson object to json
ObjectMapper objectMapper = new ObjectMapper();
Car car = new Car("yellow", "renault");
objectMapper.writeValueAsString(car);
Example 4: jackson object to json
val objectMapper = ObjectMapper()
val car = Car("yellow", "renault")
objectMapper.writeValueAsString(car)