Jackson使用许多动态节点对JSON进行反序列化

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonExample {
    public static void main(String[] args) throws Exception {
        String jsonString = "{\"name\":\"John\", \"age\":30, \"cars\":[\"Ford\", \"BMW\", \"Fiat\"]}";

        ObjectMapper mapper = new ObjectMapper();
        JsonNode rootNode = mapper.readTree(jsonString);

        // 访问固定字段
        String name = rootNode.path("name").asText();
        System.out.println("Name: " + name);

        // 访问动态字段
        if (rootNode.has("cars")) {
            JsonNode carsNode = rootNode.path("cars");
            if (carsNode.isArray()) {
                for (JsonNode carNode : carsNode) {
                    System.out.println("Car: " + carNode.asText());
                }
            }
        }
    }
}

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;

import java.io.IOException;

public class CustomDeserializerExample {
    public static void main(String[] args) throws Exception {
        String jsonString = "{\"name\":\"John\", \"age\":30, \"cars\":[\"Ford\", \"BMW\", \"Fiat\"]}";

        ObjectMapper mapper = new ObjectMapper();
        SimpleModule module = new SimpleModule();
        module.addDeserializer(MyData.class, new MyDataDeserializer());
        mapper.registerModule(module);

        MyData data = mapper.readValue(jsonString, MyData.class);
        System.out.println(data);
    }

    static class MyData {
        private String name;
        private int age;
        private JsonNode cars;

        // Getters and setters

        @Override
        public String toString() {
            return "MyData{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    ", cars=" + cars +
                    '}';
        }
    }

    static class MyDataDeserializer extends JsonDeserializer<MyData> {
        @Override
        public MyData deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
            JsonNode node = p.getCodec().readTree(p);
            MyData data = new MyData();
            data.setName(node.path("name").asText());
            data.setAge(node.path("age").asInt());
            data.setCars(node.path("cars"));
            return data;
        }
    }
}