1，实体类，在实体类中在要转换的字段上加上该注解@JsonSerialize(using = Date2LongSerializer.class)

package com.san.dto;import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.san.dataobject.OrderDetail;
import com.san.enums.OrderStatusEnum;
import com.san.enums.PayStatusEnum;
import com.san.utils.EnumUtil;
import com.san.utils.serializer.Date2LongSerializer;
import lombok.Data;import java.math.BigDecimal;
import java.util.Date;
import java.util.List;public class OrderDTO {/** 订单id. */private String orderId;/** 买家名字. */private String buyerName;/** 买家手机号. */private String buyerPhone;/** 买家地址. */private String buyerAddress;/** 买家微信Openid. */private String buyerOpenid;/** 订单总金额. */private BigDecimal orderAmount;/** 订单状态, 默认为0新下单. */private Integer orderStatus;/** 支付状态, 默认为0未支付. */private Integer payStatus;/** 创建时间. */@JsonSerialize(using = Date2LongSerializer.class)private Date createTime;/** 更新时间. */@JsonSerialize(using = Date2LongSerializer.class)private Date updateTime;List<OrderDetail> orderDetailList;public String getOrderId() {return orderId;}public void setOrderId(String orderId) {this.orderId = orderId;}public String getBuyerName() {return buyerName;}public void setBuyerName(String buyerName) {this.buyerName = buyerName;}public String getBuyerPhone() {return buyerPhone;}public void setBuyerPhone(String buyerPhone) {this.buyerPhone = buyerPhone;}public String getBuyerAddress() {return buyerAddress;}public void setBuyerAddress(String buyerAddress) {this.buyerAddress = buyerAddress;}public String getBuyerOpenid() {return buyerOpenid;}public void setBuyerOpenid(String buyerOpenid) {this.buyerOpenid = buyerOpenid;}public BigDecimal getOrderAmount() {return orderAmount;}public void setOrderAmount(BigDecimal orderAmount) {this.orderAmount = orderAmount;}public Integer getOrderStatus() {return orderStatus;}public void setOrderStatus(Integer orderStatus) {this.orderStatus = orderStatus;}public Integer getPayStatus() {return payStatus;}public void setPayStatus(Integer payStatus) {this.payStatus = payStatus;}public Date getCreateTime() {return createTime;}public void setCreateTime(Date createTime) {this.createTime = createTime;}public Date getUpdateTime() {return updateTime;}public void setUpdateTime(Date updateTime) {this.updateTime = updateTime;}public List<OrderDetail> getOrderDetailList() {return orderDetailList;}public void setOrderDetailList(List<OrderDetail> orderDetailList) {this.orderDetailList = orderDetailList;}@JsonIgnorepublic OrderStatusEnum getOrderStatusEnum() {return EnumUtil.getByCode(orderStatus, OrderStatusEnum.class);}@JsonIgnorepublic PayStatusEnum getPayStatusEnum() {return EnumUtil.getByCode(payStatus, PayStatusEnum.class);}
}

,2，负责转换的类

package com.san.utils.serializer;import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;import java.io.IOException;
import java.util.Date;public class Date2LongSerializer extends JsonSerializer<Date> {@Overridepublic void serialize(Date date, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException, JsonProcessingException {jsonGenerator.writeNumber(date.getTime() / 1000);}
}

数据存储在数据库中的格式：

转换后的效果（返回给前端的json格式）：