参考链接出处

https://blog.csdn.net/qq_42937522/article/details/110310826

修改后的代码(包括引用的出处)

import cn.hutool.core.date.DatePattern;
import cn.hutool.core.date.LocalDateTimeUtil;
import cn.hutool.core.util.StrUtil;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import org.springframework.boot.autoconfigure.jackson.Jackson2ObjectMapperBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.converter.Converter;

import java.io.IOException;
import java.time.LocalDateTime;

/**
 * @author hanfeng
 * @date 2021/11/9
 */
/**
 * jackson全局配置java8 LocalDateTime的序列化 全局配置时间返回格式
 */
@Configuration
public class JacksonCustomizerConfig {

    /**
     * description:适配自定义序列化和反序列化策略
     */
    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
        return builder -> {
            builder.serializerByType(LocalDateTime.class, new LocalDateTimeSerializer());
            builder.deserializerByType(LocalDateTime.class, new LocalDateTimeDeserializer());
        };
    }

    /**
     * description:序列化
     * LocalDateTime序列化为yyyy-MM-dd HH:mm:ss
     */
    public static class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {
        @Override
        public void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider serializers)
                throws IOException {
            if (value != null) {
                String timestamp = LocalDateTimeUtil.format(value, DatePattern.NORM_DATETIME_PATTERN);
                gen.writeNumber(timestamp);
            }
        }
    }

    /**
     * description:反序列化
     * 解析ISO时间序列化为LocalDateTime
     */
    public static class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {
        @Override
        public LocalDateTime deserialize(JsonParser p, DeserializationContext deserializationContext)
                throws IOException {
            String timestamp = p.getValueAsString();
            if (StrUtil.isNotEmpty(timestamp)) {
                return LocalDateTimeUtil.parse(timestamp);
            } else {
                return null;
            }
        }
    }

    /**
     * description:LocalDateTime转换器，用于转换RequestParam和PathVariable参数
     * 接收解析ISO时间——>LocalDateTime
     */
    @Bean
    public Converter<String, LocalDateTime> localDateTimeConverter() {
        return new Converter<String, LocalDateTime>() {
            @Override
            public LocalDateTime convert(String source) {
                //毫秒级时间戳转LocalDateTime
                return LocalDateTimeUtil.parse(source);
            }
        };
    }
}

有解释不清问题请留言,希望能帮到你!