使用java servlet的CRUD json文件

Question

我想将java servlet方法创建为Create Update或Delete Json file.In json文件是关于Dog类的信息。 这里是来源，还没有完成 这是狗类

public class Dog {
private String name;
private int age;
private int height;

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}

public int getHeight() {
    return height;
}

public void setHeight(int height) {
    this.height = height;
}

}

这是CreateServlet。

import com.google.gson.Gson;

import javax.servlet.http.HttpServlet;
import java.io.FileWriter;

    public class CreateServlet extends HttpServlet {
    public static void main(String[] args) {
        Dog dog = new Dog();
        dog.setAge(20);
        dog.setHeight(15);
        dog.setName("name");

        Gson gson = new Gson();
        try {
            FileWriter writer = new FileWriter("C://tojson.json");
            gson.toJson(dog, writer);
        } catch (Exception exp) {
            System.out.println(exp.getMessage());
        }

    }
}

如何处理Servlet方法的CRUD json文件？谢谢