使用gson在java中读取json对象文件保持获取空值

<!-- Maven -->
<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.8</version>
</dependency>

// Gradle
implementation 'com.google.code.gson:gson:2.8.8'

{
  "name": "John",
  "age": 30,
  "city": null
}

public class Person {
    private String name;
    private int age;
    private String city;

    // Getters and setters
}

import com.google.gson.Gson;
import java.io.FileReader;

public class Main {
    public static void main(String[] args) {
        Gson gson = new Gson();

        try (FileReader reader = new FileReader("path/to/json/file.json")) {
            Person person = gson.fromJson(reader, Person.class);
            System.out.println("Name: " + person.getName());
            System.out.println("Age: " + person.getAge());
            System.out.println("City: " + person.getCity());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}