使用Jackson从POJO形成嵌套JSON

import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) {
        // 创建POJO对象
        Person person = new Person("John", 25, new Address("123 Street", "City"));

        // 创建ObjectMapper对象
        ObjectMapper objectMapper = new ObjectMapper();

        try {
            // 执行转换
            String json = objectMapper.writeValueAsString(person);
            System.out.println(json);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

class Person {
    private String name;
    private int age;
    private Address address;

    // 构造方法、getter和setter省略

    public Person(String name, int age, Address address) {
        this.name = name;
        this.age = age;
        this.address = address;
    }
}

class Address {
    private String street;
    private String city;

    // 构造方法、getter和setter省略

    public Address(String street, String city) {
        this.street = street;
        this.city = city;
    }
}