多个嵌套实体上的 Spring JPA 双向关系

Question

我知道过去有多个关于使用 spring jpa 的双向关系的问题，但我的情况有点不同，因为我使用 3 个实体和 2 个关系来实现医疗系统

我有 3 个实体：医生/患者/预约

这是 3 个实体的代码 请注意所有已实现的 setter 、 getter 和构造函数，但为了清楚起见，此处省略了

患者分类

@Entity
public class resPatient {
@Id
@GeneratedValue( strategy= GenerationType.IDENTITY )
private long code;
private String name;
private String gender;
private String email;
private String mobile;
private int age;

private String notes;


@OneToMany(mappedBy = "patient")
List<resPackageMembership> memberships;

@OneToMany(mappedBy = "patient")
List<resAppointment> appointments;

@OneToMany(fetch = FetchType.LAZY,mappedBy = "patient")
List<resMedImage> medImages;

医生类

 @Entity
 public class resDoctor {

@Id
@GeneratedValue( strategy= GenerationType.IDENTITY )
private long code;
private String name;
private String mobile;



private String email;
private String gender;
private int age;
private  String speciality;

@OneToMany(mappedBy = "doctor")
List<resAppointment> appointments;

约会类

@Entity
public class resAppointment {

@Id
@GeneratedValue( strategy= GenerationType.IDENTITY )
private long code;
private String speciality;
@Basic
@Temporal(TemporalType.TIMESTAMP)
private Date dateCreated;


@Basic
@Temporal(TemporalType.TIMESTAMP)
private Date dateToVisit;
private String status;
private String notes;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "doctorCode")
private resDoctor doctor;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "patientCode")
private resPatient patient;

我的医疗系统应该工作的方式是，当我让病人使用我的 restful 控制器时，我想要所有的病人数据，包括他的预约，但这会导致一个无限循环，因为预约的医生也有预约等等.

我不能使用@JSONIGNORE，因为我希望有两个关系让病人预约，这应该让医生没有预约数组，并且不应该有任何病人数据，因为我已经在病人对象中

Answer 1

作为一般的最佳实践，建议将实体与用于其余控制器的数据传输对象分开。使用 DTO，您可以更好地控制要在其中包含和序列化哪些数据，以避免循环引用。 如果您喜欢查看https://bootify.io，它会根据您的数据库架构生成 DTO，但您仍然需要定义/构建自定义端点。

Answer 2

我最近开发了一个名为beanknife 的注释处理器，它支持从任何类生成DTO。您需要通过注释进行配置。但是你不需要改变原来的类。该库支持在单独的类上进行配置。当然，您可以选择您想要的和不需要的属性。您可以通过配置类中的静态方法添加新属性。对于您的问题：

// this will generate a DTO class named "resPatientView". 
// You can change this name using genName attribute.
@ViewOf(value=resPatient.class, includePattern = ".*")
public class PatientViewConfigure {
    // here tell the processor to automatically convert the property appointments from List<resAppointment> to List<resAppointmentWithoutPatient>. 
    // resAppointmentWithoutPatient is the generated class configured at the following. 
    // Note, although at this moment it not exists and your idea think it is an error. 
    // this code really can be compiled, and after compiled, all will ok.
    @OverrideViewProperty("appointments")
    private List<resAppointmentWithoutPatient> appointments;
}

// here generated a class named resAppointmentWithoutPatient whick has all properties of resAppointment except patient
@ViewOf(value=resAppointment.class, genName="resAppointmentWithoutPatient", includePattern = ".*", excludes={"patient"})
public class AppointmentWithoutPatientViewConfigure {
    // the doctor property will be converted to its dto version which defined by the configure class DoctorWithoutAppointmentsViewConfigure.
    @OverrideViewProperty("doctor")
    private resDoctorWithoutAppointments doctor;
}

// here we generate a class which has all properties of resDoctor except appointments
@ViewOf(value=resDoctor.class, genName="resDoctorWithoutAppointments", includePattern = ".*", excludes={"appointments"})
public class DoctorWithoutAppointmentsViewConfigure {}

// in you rest controller. return the dto instead of the entities.
resPatient patient = ...
resPatientView dto = resPatientView.read(patient);
List<resPatient> patients = ...
List<resPatientView> dto = resPatientView.read(patients);

最后，类 resPatientView 将与 resPatient 具有相同的形状，只是它的约会没有患者属性，并且它的医生属性被替换为没有约会属性的版本。

这里有更多examples。 1.10 版本已准备就绪。将修复一些错误并支持由spring管理的configure bean。