重新整理了新版JSON工具类和一些见解

封装好了，工具类，直接粘贴就好了:所需依赖 springboot，hutool

package com.jmj.gulimall.product.utils;

import cn.hutool.core.bean.BeanUtil;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.util.StdDateFormat;
import com.jmj.gulimall.product.vo.spu.Attr;
import lombok.*;

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

public class JsonUtils {

    private final static ObjectMapper objectMapper;

    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    @EqualsAndHashCode(callSuper = true)//不加这个情况下重写的Hashcode和Equals 不会比较父类属性值
    @ToString(callSuper = true)//包括父类
    @JsonIgnoreProperties({"attrValue","attrId","attrName"})//这个注解可以忽略父类属性,不需要spring环境
    public static class Energy extends Attr {
        @JsonIgnore//忽略本类字段
        private String name;
        private Date time;
    }

    public static ObjectMapper instance(DateFormat dateFormat){
        ObjectMapper objectMapper = new ObjectMapper();
        //{"name":"边杰","time":"2024-06-21T10:43:43.480+0000"}
        objectMapper.setDateFormat(dateFormat);//中间没有:号
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);//禁用转换时间戳
        // 序列化时忽略未知属性
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        // 禁用忽略大小写的特性
        objectMapper.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, false);

        // 设置序列化时不包含空属性
        // objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL); // 不包括null值
        objectMapper.setSerializationInclusion(JsonInclude.Include.ALWAYS); // 全部
        return objectMapper;
    }
    public static ObjectMapper instance(){
        return instance(new StdDateFormat().withColonInTimeZone(false));
    }
    static {
       objectMapper = instance();
    }
    public static DateFormat format(){
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return simpleDateFormat;
    }

    public static String getJson(Object obj, boolean exIsThrow) {
        try {
            return objectMapper.writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            if (exIsThrow) {
                throw new RuntimeException("JSON解析异常 e=" + e.getMessage());
            } else {
                return null;
            }

        }
    }

    public static String getJson(Object obj) {
        return getJson(obj, false);
    }

    public static <R> R getObj(String json, Class<R> clazz, boolean exIsThrow) {
        try {
            return objectMapper.readValue(json, clazz);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            if (exIsThrow) {
                throw new RuntimeException("JSON解析异常 e=" + e.getMessage());
            } else {
                return null;
            }
        }
    }
    public static <R> R getObj(String json, Class<R> clazz) {
        return getObj(json, clazz, false);
    }

    public static <T> T getObj(String json,TypeReference<T> type, boolean exIsThrow) {
        try {
            return objectMapper.readValue(json, type);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            if (exIsThrow) {
                throw new RuntimeException("JSON解析异常 e=" + e.getMessage());
            } else {
                return null;
            }
        }

    }

    public static <T> T getObj(String json,TypeReference<T> type) {
        return getObj(json, type,false);
    }


    public static void main(String[] args) throws JsonProcessingException {
//        List<Energy> list = Arrays.asList(new Energy("边界", new Date()), new Energy("边界", new Date()), new Energy("边界", new Date()));
//        String s = getJson(list);
//        System.out.println(s);
//        List<Energy> energy = getObj("[{\"attrId\":\"123\",\"attrName\":null,\"name\":\"边界\",\"time\":\"2024-06-21T11:59:00.118+0000\"},{\"attrId\":null,\"attrName\":null,\"name\":\"边界\",\"time\":\"2024-06-21T11:59:00.118+0000\"},{\"attrId\":null,\"attrName\":null,\"name\":\"边界\",\"time\":\"2024-06-21T11:59:00.118+0000\"}]",
//                new TypeReference<List<Energy>>() {},true);
//        System.out.println(energy);

//        System.out.println(instance(format()).writeValueAsString(list));


        Energy energy = new Energy("边界", new Date());
        energy.setAttrId(123L);
        energy.setAttrName("a");
        energy.setAttrValue("as");

        System.out.println(getJson(energy));
        
        
        Attr attr = new Attr();
        //父类属性也会Copy过来
        BeanUtil.copyProperties(energy,attr);
        System.out.println(attr);

    }


}