问题描述
如何使用org.mapstruct框架将一对多关系映射？
DTO类：
componentDidMount() {
getTime('Europe/London')
.then((response) => this.setState({ london: response });
}
域类-
@Data
public class ScheduledJobDTO {
private String jobName;
private String jobGroup;
private String jobClass;
private String cronExpression;
private Boolean cronJob;
private Long repeatTime;
private Integer repeatCount;
private Set<ScheduledJobParamsDTO> paramtersDTOs;
}
@Data
@EqualsAndHashCode
public class ScheduledJobParamsDTO {
String name;
String value;
}
映射器类-
@Data
@Entity
@Table(name = "scheduled_job")
public class ScheduledJob {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(name = "job_name")
private String jobName;
@Column(name = "job_group")
private String jobGroup;
@Column(name = "job_class")
private String jobClass;
@Column(name = "cron_expression")
private String cronExpression;
@Column(name = "is_cron_job")
private Boolean cronJob;
@Column(name = "repeat_time")
private Long repeatTime;
@Column(name = "repeat_count")
private Integer repeatCount;
@Column(name = "trigger_start_date")
private LocalDate triggerStartDate;
@Column(name = "trigger_end_date")
private LocalDate triggerEndDate;
@Column(name = "created_at")
private LocalDate createdAt;
@Column(name = "modified_at")
private LocalDate modifiedAt;
@Column(name = "is_active")
private Boolean active;
@OnetoMany(mappedBy = "scheduledJob")
private Set<ScheduledJobParams> parameters;
}
@Data
@Entity
@Table(name = "scheduled_job_params")
@EqualsAndHashCode
public class ScheduledJobParams {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
Long id;
@ManyToOne(fetch = FetchType.LAZY,optional = false)
@JoinColumn(name = "scheduled_job_id",nullable = false)
ScheduledJob scheduledJob;
String name;
String value;
}
现在，上面的映射器正在映射ScheduledJob和ScheduledJobParams，但是ScheduledJobParams引用了ScheduledJob。
如何将引用ScheduledJob映射到ScheduledJobParams？
解决方法
您可以通过@AfterMapping和@MappedTarget来实现。参考文档12.2. Mapping customization with before-mapping and after-mapping methods中对此进行了说明。
// Java 8+ otherwise you need to use an abstract class and a for-loop instead
@Mapper(componentModel = "spring")
public interface ScheduledJobMapper {
@Mapping(target = "parameters",source = "paramtersDTOs")
ScheduledJob mapToDomain(ScheduledJobDTO dto);
@AfterMapping
default void after(@MappingTarget ScheduledJob domain,ScheduledJobDTO dto) {
domain.getParameters().forEach(scheduledJobParams -> {
scheduledJobParams.setScheduledJob(domain);
});
}
}
但是，我确定当您从 DTO 映射回实体时，您不需要填写双向关系（这就是您的理解）请参阅“域” ）。请注意，如果处理不当，请打印出或序列化此类对象，即将其序列化为JSON或XML，并抛出java.lang.StackOverflowError。