实现对象字段在转换为 JSON 时大小写保持不变

当个胖子 / 2024-10-22 / 原文

实现对象字段在转换为 JSON 时大小写保持不变

预期效果：对象中字段名是 Age，NAME
转成json后：{"Age":"12","NAME":"张三"}
使用场景：给外系统传参数rest接口参数时，对方要求；

方式一使用 Jackson 的@JsonProperty注解

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.ObjectMapper;

class Person {
    private String name;
    @JsonProperty("Age")  // 加了这个注解的可以保持大小写不变
    private int age;

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

    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 class JsonCasePreservationExample {
    public static void main(String[] args) throws Exception {
        Person person = new Person("Alice", 30);
        ObjectMapper objectMapper = new ObjectMapper();
        String json = objectMapper.writeValueAsString(person);
        System.out.println(json);
    }
}

方式二使用gson

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

class Person {
    private String name;
    private int Age;

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

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return Age;
    }

    public void setAge(int age) {
        Age = age;
    }
}

public class GsonCasePreservationExample {
    public static void main(String[] args) {
        Person person = new Person("Alice", 30);
        Gson gson = new GsonBuilder()
               .setFieldNamingPolicy(com.google.gson.FieldNamingPolicy.IDENTITY)
               .create();
        String json = gson.toJson(person);
        System.out.println(json);
    }
}