平常我们工作中基本最多两级嵌套，但是有时候难免会遇到三级嵌套的业务场景，笔者最近就碰到了，使用一般的嵌套发现赋值为空，这可难倒了菜逼的我，后来在stackoverflow的帮助下终于搜到了解决办法，完美解决了问题 ，总结一下，方便有需要的同学，下面直接上栗子：
首先上实体类：三级嵌套如下 （电站 -----> 电桩 ---->电枪）
电站实体类 (实体为JPA写法，不影响mybatis的使用)
package com.weima.cecapp.entities;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.hibernate.annotations.BatchSize;
import org.hibernate.annotations.GenericGenerator;
import javax.persistence.*;
import java.util.Collections;
import java.util.List;
import java.util.Set;
@NoArgsConstructor
@Data
@Entity
@Table(name = "station_info")
public class StationInfo {
/**
* Auto-generated primary key.
*/
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "org.hibernate.id.UUIDGenerator")
@Column(unique = true, nullable = false, updatable = false)
private String id;
@Column(name = "station_id")
private String stationId;
@Column(name = "operator_id")
private String operatorId;
@Column(name = "equipment_owner_id")
private String equipmentOwnerId;
@Column
private String stationName;
@Column
private String countryCode;
@Column
private String areaCode;
@Column
private String address;
@Column
private String stationTel;
@Column
private String serviceTel;
@Column
private Integer stationType;
@Column
private Integer stationStatus;
@Column
private Integer parkNums;
@Column
private Double stationLng;
@Column
private Double stationLat;
@Column
private String siteGuide;
@Column
private Integer construction;
@OneToMany(fetch = FetchType.LAZY, cascade = {CascadeType.ALL}, orphanRemoval = true, mappedBy = "ownerStationInfo")
private List<StationPicture> pictures;
@Column
private String matchCars;
@Column
private String parkInfo;
@Column
private String busineHours;
@Column(name = "busine_hours_in_milliseconds")
private Long busineHoursInMilliseconds;
@Column
private String electricityFee;
@Column
private String serviceFee;
@Column
private String parkFee;
@Column
private String payment;
@Column
private Integer supportOrder;
@Column
private String remark;
@OneToMany(fetch = FetchType.LAZY, cascade = {CascadeType.ALL}, orphanRemoval = true, mappedBy = "ownerStationInfo")
@BatchSize(size = 20)
private List<EquipmentInfo> equipmentInfos;
}
电站图片实体
package com.weima.cecapp.entities;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.ToString;
import org.hibernate.annotations.GenericGenerator;
import javax.persistence.*;
@Data
@Entity
@EqualsAndHashCode(of = {"url"})
@ToString(exclude = {"ownerStationInfo"})
@Table(name = "station_picture")
public class StationPicture {
/**
* Auto-generated primary key.
*/
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "org.hibernate.id.UUIDGenerator")
@Column(unique = true, nullable = false, insertable = true, updatable = false)
private String id;
@ManyToOne(fetch = FetchType.EAGER, optional = false)
@JoinColumn(nullable = false, updatable = false)
private StationInfo ownerStationInfo;
@Column
private String url;
}
电桩实体类
package com.weima.cecapp.entities;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.ToString;
import org.hibernate.annotations.BatchSize;
import org.hibernate.annotations.GenericGenerator;
import javax.persistence.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Collections;
import java.util.List;
@Data
@Entity
@EqualsAndHashCode(of = {"equipmentId"})
@ToString(exclude = {"ownerStationInfo"})
@Table(name = "equipment_info")
public class EquipmentInfo {
/**
* Auto-generated primary key.
*/
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "org.hibernate.id.UUIDGenerator")
@Column(unique = true, nullable = false, updatable = false)
private String id;
@Column(name = "equipment_id")
private String equipmentId;
@ManyToOne(fetch = FetchType.EAGER, optional = false)
@JoinColumn(nullable = false, updatable = false)
private StationInfo ownerStationInfo;
@Column(name = "manufacturer_id")
private String manufacturerId;
@Column
private String manufacturerName;
@Column
private String equipmentModel;
@Column
private String productionDate;
public String getProductionDate() {
String format = null;
if (this.productionDate != null) {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
try {
format = sdf.format(sdf.parse(this.productionDate));
} catch (ParseException e) {
e.printStackTrace();
}
return format;
}
return format;
}
@Column
private String equipmentType;
@OneToMany(fetch = FetchType.LAZY, orphanRemoval = true, mappedBy = "ownerEquipmentInfo", cascade = {CascadeType.PERSIST})
@BatchSize(size = 20)
private List<ConnectorInfo> connectorInfos;
@Column
private Double equipmentLng;
@Column
private Double equipmentLat;
@Column
private Double power;
@Column
private String equipmentName;
@Column(name = "equipment_no")
//cpo's custom equipmentId mostly for Evstation
private String equipmentNo;
}
电枪实体类
package com.weima.cecapp.entities;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.ToString;
import org.hibernate.annotations.GenericGenerator;
import javax.persistence.*;
@Data
@Entity
@EqualsAndHashCode(of = {"connectorId"})
@ToString(exclude = {"ownerEquipmentInfo"})
@Table(name = "connector_info")
public class ConnectorInfo {
/**
* Auto-generated primary key.
*/
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "org.hibernate.id.UUIDGenerator")
@Column(unique = true, nullable = false, updatable = false)
private String id;
@ManyToOne(fetch = FetchType.EAGER, optional = false)
@JoinColumn(nullable = false, updatable = false)
private EquipmentInfo ownerEquipmentInfo;
@Column(name = "connector_id")
private String connectorId;
@Column
private String connectorName;
@Column
private Integer connectorType;
@Column
private Integer voltageUpperLimits;
@Column
private Integer voltageLowerLimits;
@Column
private Integer current;
@Column
private Double power;
@Column
private String parkNo;
@Column
private Integer nationalStandard;
@Column(name = "connector_no")
//cpo's custom connectorId mostly for Evstation
private String connectorNo;
}
mapper 文件的resultMap映射及Sql语句的书写，要特别注意映射关系
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.hubject.cecapp.mapper.StationInfoAnyueMapper">
<resultMap id="templateListResp" type="com.hubject.cecapp.entities.EquipmentInfo">
<!-- 充电桩信息-->
<id column ="id " property="id"/>
<result column="equipment_id " property="equipmentId"/>
<result column="equipment_lat " property="manufacturerName"/>
<result column="equipment_lng " property="equipmentModel"/>
<result column="equipment_model " property="productionDate"/>
<result column="equipment_name " property="manufacturerId"/>
<result column="equipment_type " property="equipmentType"/>
<result column="manufacturer_id " property="equipmentLng"/>
<result column="manufacturer_name " property="equipmentLat"/>
<result column="power " property="power"/>
<result column="production_date " property="equipmentName"/>
<result column="owner_station_info_id " property="equipmentNo"/>
<!-- 充电枪 信息列表 -->
<collection property="connectorInfos" columnPrefix="f_" ofType="com.hubject.cecapp.entities.ConnectorInfo">
<id column="id" property="id"/>
<result column="connector_id" property="connectorId"/>
<result column="connector_name" property="connectorName"/>
<result column="connector_type" property="connectorType"/>
<result column="voltage_upper_limits" property="voltageUpperLimits"/>
<result column="voltage_lower_limits" property="voltageLowerLimits"/>
<result column="current" property="current"/>
<result column="power" property="power"/>
<result column="park_no" property="parkNo"/>
<result column="national_standard" property="nationalStandard"/>
<result column="connector_no" property="connectorNo"/>
</collection>
</resultMap>
<!-- 通用查询映射结果 -->
<resultMap id="Base3ResultMap" type="com.hubject.cecapp.entities.StationInfo">
<result column="id" property="id"/>
<result column="address" property="address"/>
<result column="area_code" property="areaCode"/>
<result column="busine_hours" property="busineHours"/>
<result column="construction" property="construction"/>
<result column="country_code" property="countryCode"/>
<result column="electricity_fee" property="electricityFee"/>
<result column="equipment_owner_id" property="equipmentOwnerId"/>
<result column="station_id" property="stationId"/>
<result column="operator_id" property="operatorId"/>
<result column="station_name" property="stationName"/>
<result column="station_tel" property="stationTel"/>
<result column="service_tel" property="serviceTel"/>
<result column="station_type" property="stationType"/>
<result column="station_status" property="stationStatus"/>
<result column="park_nums" property="parkNums"/>
<result column="station_lng" property="stationLng"/>
<result column="station_lat" property="stationLat"/>
<result column="site_guide" property="siteGuide"/>
<result column="match_cars" property="matchCars"/>
<result column="park_info" property="parkInfo"/>
<result column="busine_hoursIn_milliseconds" property="busineHoursInMilliseconds"/>
<result column="service_fee" property="serviceFee"/>
<result column="park_fee" property="parkFee"/>
<result column="payment" property="payment"/>
<result column="support_order" property="supportOrder"/>
<result column="remark" property="remark"/>
<result column="templateListResp" property="remark"/>
<collection property="equipmentInfos" columnPrefix="t_" resultMap="templateListResp"/>
</resultMap>
-- 要特别注意的是 t_f_ 的前缀，这个关乎到映射不映射上的根本。
<select id="queryAreaForAnyoCharging" resultMap="Base3ResultMap">
select
a.id as id,
a.station_id as station_id,
a.operator_id as operator_id,
a.equipment_owner_id as equipment_owner_id,
a.station_name as station_name,
a.country_code as country_code,
a.area_code as area_code,
a.address as address,
a.station_tel as station_tel,
a.service_tel as service_tel,
a.station_type as station_type,
a.station_status as station_status,
a.park_nums as park_nums,
a.station_lng as station_lng,
a.station_lat as station_lat,
a.site_guide as site_guide,
a. construction as construction,
a.match_cars as match_cars,
a.park_info as park_info,
a.busine_hours as busine_hours,
a.busine_hours_in_milliseconds as busine_hours_in_milliseconds,
a. electricity_fee as electricity_fee,
a. service_fee as service_fee,
a. park_fee as park_fee,
a. payment as payment,
a. support_order as support_order,
a.remark as remark
,
e.id as t_id ,
e.equipment_id as t_equipment_id ,
e.equipment_lat as t_equipment_lat ,
e.equipment_lng as t_equipment_lng ,
e.equipment_model as t_equipment_model ,
e.equipment_name as t_equipment_name ,
e.equipment_type as t_equipment_type ,
e.manufacturer_id as t_manufacturer_id ,
e.manufacturer_name as t_manufacturer_name ,
e.power as t_power ,
e.production_date as t_production_date ,
e.owner_station_info_id as t_owner_station_info_id ,
e.equipment_no as t_equipment_no
,
c.id as t_f_id ,
c.power as t_f_power ,
c.current as t_f_current ,
c.park_no as t_f_park_no ,
c.connector_id as t_f_connector_id ,
c.connector_name as t_f_connector_name ,
c.connector_type as t_f_connector_type ,
c.connector_no as t_f_connector_no ,
c.national_standard as t_f_national_standard ,
c.voltage_lower_limits as t_f_voltage_lower_limits ,
c.voltage_upper_limits as t_f_voltage_upper_limits ,
c.owner_equipment_info_id as t_f_owner_equipment_info_id
from station_info a join equipment_info e on a.id = e.owner_station_info_id
join connector_info c on e.id = c.owner_equipment_info_id
where a.operator_id='MA59J8YL8'
</select>
</mapper>
希望为遇到同样需求的同学提供到帮助。
到此这篇关于myBatis实现三级嵌套复杂对象的赋值问题的文章就介绍到这了,更多相关myBatis三级嵌套复杂对象的赋值内容请搜索呐喊教程以前的文章或继续浏览下面的相关文章希望大家以后多多支持呐喊教程！
声明：本文内容来源于网络，版权归原作者所有，内容由互联网用户自发贡献自行上传，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任。如果您发现有涉嫌版权的内容，欢迎发送邮件至：notice#nhooo.com（发邮件时，请将#更换为@）进行举报，并提供相关证据，一经查实，本站将立刻删除涉嫌侵权内容。