Java日期时间字段JSON序列化为时间戳，原来这么简单？

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

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

public class TimestampLocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {

    public static final TimestampLocalDateTimeSerializer INSTANCE = new TimestampLocalDateTimeSerializer();

    @Override
    public void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
        gen.writeNumber(value.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli());
    }

}

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;

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


public class TimestampLocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {

    public static final TimestampLocalDateTimeDeserializer INSTANCE = new TimestampLocalDateTimeDeserializer();

    @Override
    public LocalDateTime deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
        return LocalDateTime.ofInstant(Instant.ofEpochMilli(p.getValueAsLong()), ZoneId.systemDefault());
    }

}

SimpleModule simpleModule = new SimpleModule();
        simpleModule
                // 新增 LocalDateTime 序列化、反序列化规则，使用 Long 时间戳
                .addSerializer(LocalDateTime.class, TimestampLocalDateTimeSerializer.INSTANCE)
                .addDeserializer(LocalDateTime.class, TimestampLocalDateTimeDeserializer.INSTANCE);
// 注册模块.
objectMapper.registerModule(module);

  /** 支付时间 */
  @JsonProperty("pay_time")
  @JsonDeserialize(using = TimestampLocalDateTimeDeserializer.class)
  @JsonSerialize(using = TimestampLocalDateTimeSerializer.class)
  private LocalDateTime payTime;