无法将两个Neo4j实例与Spring Boot/Spring数据Neo4j一起使用

Question

预期行为

Trying to use two Neo4j instances with Spring boot and Spring data Neo4j

当前行为

Able to use only one Neo4j instances. Unable to use two repositories.

复制步骤（针对错误）

1. Run two Neo4j Instances
2. Create Data source configuration for both Neo4j Instances using spring boot.
3. Use Repository to access the Node entity
4. It will throw error

语境

假设我正在经营一家图书馆，并将书籍出租给其他用户。如果用户从我这里租用书籍，那么他们的存储库中将显示相同的节点详细信息，我将允许他们通过我的应用程序编辑节点实体（如添加关键字、添加书籍的亮点等）

因此，在这两个存储库中，节点详细信息将是相同的。

下面是应用程序。两个Neo4j存储库的属性详细信息。

我的Neo4j存储库详细信息

spring.data.neo4j.uri=bolt://localhost:7687
spring.data.neo4j.username=neo4j
spring.data.neo4j.password=neo4j

租用用户的Neo4j存储库详细信息（通过在其他机器上运行的超文本传输协议访问）

rental.data.neo4j.uri=bolt://...:7687
rental.data.neo4j.username=neo4j
rental.data.neo4j.password=neo4j

以下是租赁用户的Neo4j配置：

@configuration
@EnableNeo4jRepositories(basePackages = "com.metadata.dao.rentallibrary", sessionFactoryRef = "rentalSessionFactory", transactionManagerRef = "rentalUsertransactionManager")
@EnableTransactionManagement
@EntityScan("com.metadata.dao")
public class rentalUserNeo4jConfiguration {

@Value("${rental.data.neo4j.uri}")
private String url;

@Value("${rental.data.neo4j.username}")
private String userName;

@Value("${rental.data.neo4j.password}")
private String password;

@Bean(name = "rentalSessionFactory")
public SessionFactory rentalUserSessionFactory() {
    return new SessionFactory(rentalNeo4jconfiguration(), "com.metadata.dao.rentallibrary.entity");
}

@Bean
public org.neo4j.ogm.config.Configuration rentalNeo4jconfiguration() {
    org.neo4j.ogm.config.Configuration configuration = new org.neo4j.ogm.config.Configuration.Builder().uri(url)// "
            .credentials(userName, password)
            .build();
    return configuration;
}

@Bean
public Neo4jTransactionManager rentalUsertransactionManager() {
    return new Neo4jTransactionManager(rentalUserSessionFactory());
}
}

下面是我的库的Neo4j配置详细信息：

@configuration
@EnableNeo4jRepositories(basePackages = "com.metadata.dao.mylibrary", sessionFactoryRef = "myUserSessionFactory", transactionManagerRef = "myUserTransactionManager")
@EnableTransactionManagement
public class MyUserNeo4jConfiguration {

@Value("${spring.data.neo4j.uri}")
private String url;

@Value("${spring.data.neo4j.username}")
private String userName;

@Value("${spring.data.neo4j.password}")
private String password;

@Bean(name = "myUserSessionFactory")
@Primary
public SessionFactory myUserSessionFactory() {
    return new SessionFactory(myUserconfiguration(), "com.metadata.dao.mylibrary.entity");
}

@Bean
public org.neo4j.ogm.config.Configuration myUserconfiguration() {
    org.neo4j.ogm.config.Configuration configuration = new org.neo4j.ogm.config.Configuration.Builder().uri(url)
            .credentials(userName, password)
            .build();
    return configuration;
}

@Bean
public Neo4jTransactionManager myUserTransactionManager() {
    return new Neo4jTransactionManager(myUserSessionFactory());
}
}

我正在尝试使用会话工厂访问这两个存储库（通过限定符），它工作正常。但我正试图通过存储库访问数据，我面临着这个问题。

**Accessing through SessionFactory :**

@Autowired
@Qualifier(value = "myUserSessionFactory")
SessionFactory myUserSessionFactory;

@Autowired
@Qualifier(value = "rentalUserSessionFactory")
SessionFactory rentalUserSessionFactory;

以下是我尝试通过访问数据时得到的错误详细信息：

java.lang.IllegalArgumentException: Class class com.metadata.dao.Book is not a valid entity class. Please check the entity mapping.
at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:88) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:40) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.session.Neo4jSession.save(Neo4jSession.java:469) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_141]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_141]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_141]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_141]
at org.springframework.data.neo4j.transaction.SharedSessionCreator$SharedSessionInvocationHandler.invoke(SharedSessionCreator.java:131) ~[spring-data-neo4j-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at com.sun.proxy.$Proxy81.save(Unknown Source) ~[na:na]

org.neo4j.ogm.exception.core.TransactionManagerException: Transaction is not current for this thread
at org.neo4j.ogm.session.transaction.DefaultTransactionManager.rollback(DefaultTransactionManager.java:86) ~[neo4j-ogm-core-3.1.0.jar:3.1.0]
at org.neo4j.ogm.transaction.AbstractTransaction.rollback(AbstractTransaction.java:65) ~[neo4j-ogm-api-3.1.0.jar:3.1.0]
at org.neo4j.ogm.drivers.bolt.transaction.BoltTransaction.rollback(BoltTransaction.java:61) ~[neo4j-ogm-bolt-driver-3.1.0.jar:3.1.0]
at org.neo4j.ogm.transaction.AbstractTransaction.close(AbstractTransaction.java:144) ~[neo4j-ogm-api-3.1.0.jar:3.1.0]
at org.springframework.data.neo4j.transaction.Neo4jTransactionManager.doCleanupAfterCompletion(Neo4jTransactionManager.java:379) ~[spring-data-neo4j-5.0.8.RELEASE.jar:5.0.8.RELEASE]

dao中的节点实体名称。我的图书馆。实体：账簿

dao.rentallibrary.entity节点实体名称：RentedBook

请让我知道为什么在使用Neo4j存储库时会出现此问题？我们不能将两个Neo4j存储库与Spring数据Neo4j一起使用吗

我的环境

OGM Version used: 3.1.0
Java Version used: 1.8
Neo4J Version used:3.2.3
Bolt Driver Version used (if applicable): 3.1.0
Operating System and Version: Windows
Please let me know if you need any additional information.

Answer 1

更新这已经在Spring Data Neo4j Lovelace RC1中得到解决，我们写了一个小方法：https://michael-simons.github.io/neo4j-sdn-ogm-tips/using_multiple_session_factories

感谢您将此作为GitHub第498期提交。

目前的Spring Data Neo4j版本似乎在将不同的会话工厂传播到存储库方面存在缺陷。简而言之：现在没有办法做到这一点（例如，您可以使用Spring数据JPA）。

如果您需要（并且想要）存储库，我现在无法帮助您。然而，工作是注入不同的会话工厂：

    @Autowired
    @Qualifier("myUserSessionFactory")
    private SessionFactory myUserSessionFactory;

    @Autowired
    @Qualifier("rentalUserSessionFactory")
    private SessionFactory rentalUserSessionFactory;

然后做一些类似的事情

Map<String, Object> params = new HashMap<>();
params.put("name", "test");
ThingEntity t = this.myUserSessionFactory.openSession().queryForObject(
                ThingEntity.class,
                "MATCH (n:`Thing`) WHERE n.name = $name WITH n RETURN n", params);

不管我们的代码中有什么bug，我建议使用以下配置。对于主bean（“myUserconfiguration”），使用一个配置类

package gh.neo4jogm.gh498;

import gh.neo4jogm.gh498.domain1.ThingEntity;
import org.neo4j.ogm.session.SessionFactory;
import org.springframework.boot.autoconfigure.data.neo4j.Neo4jProperties;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.neo4j.repository.config.EnableNeo4jRepositories;
import org.springframework.data.neo4j.transaction.Neo4jTransactionManager;

@Configuration
@EnableNeo4jRepositories(
    basePackages = Domain1Config.BASE_PACKAGE,
    sessionFactoryRef = "myUserSessionFactory",
    transactionManagerRef = "myUserTransactionManager"
)
@EntityScan(basePackageClasses = ThingEntity.class)
class Domain1Config {

    static final String BASE_PACKAGE = "gh.neo4jogm.gh498.domain1";

    @Primary
    @Bean
    @ConfigurationProperties("spring.data.neo4j")
    public Neo4jProperties myNeo4jProperties() {
        return new Neo4jProperties();
    }

    @Primary
    @Bean
    public org.neo4j.ogm.config.Configuration myUserconfiguration() {
        return myNeo4jProperties().createConfiguration();
    }

    @Primary
    @Bean
    public SessionFactory myUserSessionFactory() {
        return new SessionFactory(myUserconfiguration(), BASE_PACKAGE);
    }

    @Bean
    public Neo4jTransactionManager myUserTransactionManager() {
        return new Neo4jTransactionManager(myUserSessionFactory());
    }
}

基本思想是使用ConfigurationProperties将默认属性映射到neo4jproperty实例（我们的properties类），并像创建动作配置一样使用它。

对于另一个会话工厂也是如此：

package gh.neo4jogm.gh498;

import gh.neo4jogm.gh498.domain2.OtherThingEntity;
import org.neo4j.ogm.session.SessionFactory;
import org.springframework.boot.autoconfigure.data.neo4j.Neo4jProperties;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.neo4j.repository.config.EnableNeo4jRepositories;
import org.springframework.data.neo4j.transaction.Neo4jTransactionManager;

import static gh.neo4jogm.gh498.Domain2Config.BASE_PACKAGE;

@Configuration
@EnableNeo4jRepositories(
    basePackages = BASE_PACKAGE,
    sessionFactoryRef = "rentalUserSessionFactory",
    transactionManagerRef = "rentalUsertransactionManager"
)
@EntityScan(basePackageClasses = OtherThingEntity.class)
class Domain2Config {

    static final String BASE_PACKAGE = "gh.neo4jogm.gh498.domain2";

    @Bean
    @ConfigurationProperties("rental.data.neo4j")
    public Neo4jProperties rentalNeo4jProperties() {
        return new Neo4jProperties();
    }

    @Bean
    public org.neo4j.ogm.config.Configuration rentalNeo4jconfiguration() {
        return rentalNeo4jProperties().createConfiguration();
    }

    @Bean
    public SessionFactory rentalUserSessionFactory() {
        return new SessionFactory(rentalNeo4jconfiguration(), BASE_PACKAGE);
    }

    @Bean
    public Neo4jTransactionManager rentalUsertransactionManager() {
        return new Neo4jTransactionManager(rentalUserSessionFactory());
    }
}

在这里，您可以映射所有以租赁为前缀的房产。数据neo4j到另一个属性实例。