如何解决Neo4j OGM无法在保存时清除空值关系
- Neo4j社区4.0.3
- Windows 10 通过Java 11 OGM框架访问的
- 螺栓驱动程序
- 复制步骤...
我已经在下面创建了两个(helm package --dependency-update parent-chart
和Car
)类,然后运行第三个(Person
)类作为JUnit测试。我原以为最终的assertNull会通过,但是失败了:已经设置,保存,然后清除并再次保存的关系似乎并没有在最终保存中保留其清除/空值处理。
这对我来说似乎很奇怪,所以我想知道这是否是一个错误...但是接受它很可能是我所缺乏的知识。
(我想知道是否需要创建一个显式的关系类,然后使用其标识符将其删除,但是鉴于我可能不想要其他任何属性,我宁愿不要来。)
任何人都可以向我提供这方面的理解将是非常欢迎的。谢谢!
PocTest
import org.neo4j.ogm.annotation.GeneratedValue;
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.annotation.Relationship;
@NodeEntity( label = "Car" )
public class Car {
@GeneratedValue
@Id
private Long id;
@Relationship( type = "DRIVER",direction = Relationship.OUTGOING )
private Person driver;
public Long getId()
{
return this.id;
}
public Person getDriver()
{
return this.driver;
}
public void setDriver( final Person driver )
{
this.driver = driver;
}
}
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.annotation.NodeEntity;
@NodeEntity( label = "Person" )
public class Person {
@Id
private String name;
public String getName()
{
return this.name;
}
public void setName( final String name )
{
this.name = name;
}
}
解决方法
完整的解决方法“解决方案”,来自我上面的评论:
import org.neo4j.ogm.annotation.GeneratedValue;
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.annotation.Relationship;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@NodeEntity( label = "Car" )
public class Car {
@GeneratedValue
@Id
private Long id;
@JsonIgnoreProperties( { "car" } )
@Relationship( type = "DRIVEN_BY",direction = Relationship.OUTGOING )
private CarDriver drivenBy;
public Long getId()
{
return this.id;
}
public CarDriver getDrivenBy()
{
return this.drivenBy;
}
public void setDrivenBy( final CarDriver value )
{
if( this.drivenBy != null && this.drivenBy.getCar() != this )
{
this.drivenBy.setCar( null );
}
this.drivenBy = value;
if( this.drivenBy != null && this.drivenBy.getCar() != this )
{
this.drivenBy.setCar( this );
}
}
}
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.annotation.Relationship;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@NodeEntity( label = "Person" )
public class Person {
@Id
private String name;
@JsonIgnoreProperties( { "drivenBy" } )
@Relationship( type = "DRIVEN_BY",direction = Relationship.INCOMING )
private CarDriver drives;
public String getName()
{
return this.name;
}
public void setName( final String name )
{
this.name = name;
}
public CarDriver getDrives()
{
return this.drives;
}
public void setDrives( final CarDriver value )
{
if( this.drives != null && this.drives.getDriver() != this )
{
this.drives.setDriver( null );
}
this.drives = value;
if( this.drives != null && this.drives.getDriver() != this )
{
this.drives.setDriver( this );
}
}
}
import org.neo4j.ogm.annotation.EndNode;
import org.neo4j.ogm.annotation.GeneratedValue;
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.annotation.RelationshipEntity;
import org.neo4j.ogm.annotation.StartNode;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@RelationshipEntity( type = "DRIVEN_BY" )
public class CarDriver {
@GeneratedValue
@Id
private Long id;
@JsonIgnoreProperties( "drivenBy" )
@StartNode
private Car car;
@JsonIgnoreProperties( "drives" )
@EndNode
private Person driver;
public Long getId()
{
return this.id;
}
public Car getCar()
{
return this.car;
}
public void setCar( final Car car )
{
if( this.car != null && this.car.getDrivenBy() != this )
{
this.car.setDrivenBy( null );
}
this.car = car;
if( this.car != null && car.getDrivenBy() != this )
{
car.setDrivenBy( this );
}
}
public Person getDriver()
{
return this.driver;
}
public void setDriver( final Person driver )
{
if( this.driver != null && this.driver.getDrives() != this )
{
this.driver.setDrives( null );
}
this.driver = driver;
if( this.driver != null && driver.getDrives() != this )
{
driver.setDrives( this );
}
}
}
import static org.junit.jupiter.api.Assertions.assertNull;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.neo4j.ogm.config.Configuration;
import org.neo4j.ogm.session.Session;
import org.neo4j.ogm.session.SessionFactory;
import org.springframework.util.StringUtils;
public class PoCTest {
private static SessionFactory ogmSessionFactory;
@BeforeAll
private static void createSessionFactory()
{
final Configuration config = new Configuration.Builder().uri( "bolt://localhost:7687" )
.credentials( "neo4j",StringUtils.replace( "111","1","n304j" ) )
.useNativeTypes()
.verifyConnection( true )
.build();
ogmSessionFactory = new SessionFactory( config,PoCTest.class.getPackageName() );
}
private static Session getOgmSession()
{
return ogmSessionFactory.openSession();
}
@BeforeEach
void setUp()
{
getOgmSession().deleteAll( CarDriver.class );
getOgmSession().deleteAll( Car.class );
getOgmSession().deleteAll( Person.class );
}
@Test
void testCreateCarChangeDriver()
{
final Car car = new Car();
final Person fred = new Person();
fred.setName( "fred" );
final CarDriver carDriver = new CarDriver();
carDriver.setCar( car );
carDriver.setDriver( fred );
getOgmSession().save( car );
getOgmSession().delete( carDriver );
assertNull( getOgmSession().load( Car.class,car.getId() ).getDrivenBy() );
assertNull( getOgmSession().load( Person.class,fred.getName() ).getDrives() );
}
}
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