PersonJSON

Address.java

package personJson;

public class Address {
    public String country;
    public String city;
    public String street;

    @Override
    public String toString() {
      return "Country: " + country + "\n" +
              "City: " + city + "\n" +
              "Street: " + street + "\n";
    }
}

Json.java

package personJson;

import java.util.Arrays;

public class Json {
    public String name;
    public String surname;
    public String[] phones;
    public String[] sites;
    public Address address;

    @Override
    public String toString() {
        return  "Name: " + name + "\n" +
                "Surname: " + surname + "\n" +
                "Phones: " + Arrays.toString(phones) + "\n" +
                "Sites: " + Arrays.toString(sites) + "\n" +
                "Address: " + address.toString() + "\n";
    }
}

Main.java

package personJson;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Arrays;

public class Main {
    public static void main(String[] args) {

        String path = "D:\\dir\\person.txt";
        String result = null;
        try {
            result = fileToText(path);
        } catch (IOException e) {
            e.printStackTrace();
        }

        Gson gson = new GsonBuilder().create();
        Json json = gson.fromJson(result, Json.class);

        //Выводим на экран то, что нам нужно
        System.out.println(json.surname + Arrays.toString(json.sites));
        System.out.println("----------------------------------------");

        //Выводим на экран все
        System.out.println(json.toString());
    }

    public static String fileToText(String path) throws IOException {
        
        try (RandomAccessFile raf = new RandomAccessFile(path, "r")){
            byte[] buf = new byte[(int) raf.length()];
            raf.read(buf);
            return new String(buf);
        }
    }
}