扁平化JSON字符串，使用Gson或Jackson将包含每个级别键值的键转换为Map<String、String>

import com.google.gson.Gson;
import java.util.Map;

public class GsonExample {
    public static void main(String[] args) {
        String jsonString = "{\"name\":\"John\",\"age\":30,\"address\":{\"city\":\"New York\",\"country\":\"USA\"}}";

        Gson gson = new Gson();
        Map<String, String> flattenedMap = gson.fromJson(jsonString, Map.class);

        System.out.println(flattenedMap);
    }
}

import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.Map;

public class JacksonExample {
    public static void main(String[] args) {
        String jsonString = "{\"name\":\"John\",\"age\":30,\"address\":{\"city\":\"New York\",\"country\":\"USA\"}}";

        ObjectMapper objectMapper = new ObjectMapper();
        Map<String, String> flattenedMap = objectMapper.readValue(jsonString, Map.class);

        System.out.println(flattenedMap);
    }
}