JSON解析方案及json转Map反序列号，应用于支付回调通知中接收参数

JSON解析方案及json转Map反序列号，应用于支付回调通知中接收参数

1.使用 Jackson：业界标配
2.使用 Gson：轻量好用
3.使用 FastJSON：高性能

class User {
    @Expose(serialize = true)
    private int id;
    @Expose
    private String name;
    @Expose
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")    //Jackson 日期格式化
    private Date birthday;
    @JsonIgnore            //Jackson 忽略字段
    private String sex;
    @Expose
    @JsonProperty("city_name")  //Jackson 重命名字段
    private String cityName;

    @Expose(serialize = false)      //gson 忽略字段
    private String sex2;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", sex2='" + sex2 + '\'' +
                ", cityName='" + cityName + '\'' +
                '}';
    }

    public String getSex2() {
        return sex2;
    }

    public void setSex2(String sex2) {
        this.sex2 = sex2;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getCityName() {
        return cityName;
    }

    public void setCityName(String cityName) {
        this.cityName = cityName;
    }

    // Getters 和 Setters
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

1. 使用 Jackson：业界标配

package com.example.core.mydemo.json2025;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.gson.annotations.Expose;
import com.fasterxml.jackson.core.type.TypeReference;

import java.util.Date;
import java.util.Map;

public class JacksonExample {
    public static void main(String[] args) throws Exception {
        //(through reference chain: com.example.core.mydemo.json2025.User["cityName"])
        String json = "{\"id\":1,\"name\":\"张三\",\"birthday\":\"2025-03-04 10:00:00\",\"sex\":\"男\",\"city_name\":\"北京\"}";

        ObjectMapper objectMapper = new ObjectMapper();
        /**
         * JSON 转对象（反序列化）
         */
        User user = objectMapper.readValue(json, User.class);
        System.out.println(user.toString()); // 输出：User{id=1, name='张三', birthday=Tue Mar 04 18:00:00 CST 2025, sex='null', cityName='北京'}

        Map<String, Object> map = objectMapper.readValue(json, new TypeReference<Map<String, Object>>() {});
        System.out.println("map=" + map); // 输出： map={id=1, name=张三, birthday=2025-03-04 10:00:00, sex=男, city_name=北京}


        /**
         * 对象转 JSON（序列化）
         */
        user = new User();
        user.setId(1);
        user.setName("李四");
        //测试注解高级功能
        user.setBirthday(new Date());
        user.setSex("男");
        user.setCityName("上海");
        json = objectMapper.writeValueAsString(user);
        System.out.println(json); // 输出：{"id":1,"name":"李四","birthday":"2025-03-05","city_name":"上海"}
    }
}

2.使用 Gson：轻量好用

package com.example.core.mydemo.json2025;

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

import java.util.Date;
import java.util.Map;

public class GsonExample {
    public static void main(String[] args) {
        String json = "{\"id\":1,\"name\":\"王五\"}";

        Gson gson = new Gson();
        User user = gson.fromJson(json, User.class);
        System.out.println(user.getName()); // 输出：王五
        /**
         * 反序列化
         */
        Map map = gson.fromJson(json, Map.class);
        System.out.println("map=" + map); // 输出： map={id=1.0, name=王五}


        user = new User();
        user.setId(2);
        user.setName("赵六");
        //测试注解高级功能
        user.setBirthday(new Date());
        user.setSex2("男");
        user.setCityName("上海");
        /**
         * 序列化
         */
        GsonBuilder builder = new GsonBuilder();
        builder.excludeFieldsWithoutExposeAnnotation();   //配合@Expose使用，其他的字段也都要加上该注释，默认是true
        Gson gson3 = builder.create();
        json = gson3.toJson(user);
        System.out.println(json);   // 输出：{"id":2,"name":"赵六"}

    }

}

3.使用 FastJSON：高性能

package com.example.core.mydemo.json2025;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializerFeature;

import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;

public class FastJsonExample {
    public static void main(String[] args) {
        String json = "{\"id\":1,\"name\":\"小明\"}";

        User user = JSON.parseObject(json, User.class);
        System.out.println(user.getName()); // 输出：小明
        /**
         * 反序列化
         */
        Map<String, Object> map = JSON.parseObject(json, Map.class);
        System.out.println("map=" + map);  //输出： map={name=小明, id=1}  可以用于支付的异步通知接收消息


        user = new User();
        user.setId(3);
        user.setName("小红");
        //测试注解高级功能
        user.setBirthday(new Date());
        user.setSex2("男");
        user.setCityName("上海");

        //默认
        json = JSON.toJSONString(user);
        System.out.println(json);   //输出： {"birthday":1741164892016,"cityName":"上海","id":3,"name":"小红","sex2":"男"}

        //日期格式  序列化
//        第一种方法：
        JSON.DEFFAULT_DATE_FORMAT = "yyyy-MM-dd";
        json = JSON.toJSONString(user,SerializerFeature.WriteDateUseDateFormat);
        System.out.println(json); // 输出： {"birthday":"2025-03-05","cityName":"上海","id":3,"name":"小红","sex2":"男"}

//        第二种方法：
        json = JSON.toJSONStringWithDateFormat(user, "yyyy-MM-dd HH:mm:ss.SSS");
        System.out.println(json); //输出： {"birthday":"2025-03-05 16:54:52.016","cityName":"上海","id":3,"name":"小红","sex2":"男"}

    }

}