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.

重现步骤（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

上下文

假设我正在经营一个图书馆并向其他用户出租书籍。如果用户从我这里租借这本书，相同的节点详细信息将出现在他们的存储库中，我将允许他们通过我的应用程序编辑节点实体（例如添加关键字、添加有关书籍的亮点等）

因此，在两个存储库中，节点详细信息将相同。

以下是应用程序。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http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());
}
}

以下是我的库的 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（通过限定符）访问这两个存储库，它工作正常。但我正在尝试通过我面临问题的存储库访问数据。

**Accessing through SessionFactory :**

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

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

以下是错误详细信息，我在尝试通过以下方式访问数据时遇到：

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.mylibrary.entity 中的节点实体名称：书

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

请告诉我为什么在使用 Neo4j 存储库时会出现此问题？我们不能将两个 Neo4j 存储库与 Spring data neo4j 和 Spring boot 一起使用吗？还是我做错了什么？

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

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

感谢您将此作为 GitHub 问题 #498 提交。

当前的 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错误。简而言之：目前无法完成这项工作（例如，您可以使用 Spring Data JPA）。

如果您需要（并且想要）存储库，我现在无法为您提供帮助。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);

不管我们的代码有什么bug，我都推荐下面的配置。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Neo4jProperties（我们的属性类）的一个实例，并像我们创建动作配置一样使用它。

其他会话工厂也一样：

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，您将所有以rental.data.neo4j 为前缀的属性映射到另一个属性实例。