没有可用的“javax.persistence.EntityManager”类型的合格 bean：预期单个匹配 bean，但发现 2

Question

我有两个用于两个独立数据库的实体管理器配置，但是当我尝试自动连接实体管理器以配置我的 GraphQLExecutor bean 时，我收到一个异常，指出即使我指定了一个单元名称，仍有两个 bean 符合条件在 PersistenceContext 中。

例外

org.springframework.beans.factory.BeanCreationException：创建名为“graphQLExecutor”的bean时出错：资源依赖注入失败；嵌套异常是 org.springframework.beans.factory.NoUniqueBeanDefinitionException：没有可用的“javax.persistence.EntityManager”类型的合格 bean：预期的单个匹配 bean，但发现 2：org.springframework.orm.jpa.SharedEntityManagerCreator#0,org.springframework .orm.jpa.SharedEntityManagerCreator#1 at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:321) ~[spring-context-4.3.9.RELEASE.jar:4.3.9.org.RELEASE] springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) ~[spring-beans-4.3.9.

实体管理器 1

package com.ogl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;

@Configuration
@EnableJpaRepositories(basePackages = "com.ogl.system", entityManagerFactoryRef = "companyEntityManagerFactory", transactionManagerRef = "companyTransactionManager")
public class SystemJpaConfig {

  private final Environment environment;

  @Autowired
  public SystemJpaConfig(Environment environment) {
    this.environment = environment;
  }

  @Bean("systemEntityManagerFactory")
  public LocalContainerEntityManagerFactoryBean systemEntityManagerFactory() {
    LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
    entityManagerFactoryBean.setPackagesToScan("com.ogl.system");
    entityManagerFactoryBean.setPersistenceUnitName("system");
    entityManagerFactoryBean.setDataSource(systemDataSource());

    HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
    adapter.setDatabase(Database.POSTGRESQL);
    adapter.setShowSql(true);
    adapter.setGenerateDdl(false);

    entityManagerFactoryBean.setJpaVendorAdapter(adapter);

    return entityManagerFactoryBean;
  }

  @Bean
  DataSource systemDataSource() {
    DriverManagerDataSource dataSource = new DriverManagerDataSource();
    dataSource.setDriverClassName(environment.getProperty("p4.datasource.driver"));
    dataSource.setUrl(environment.getProperty("p4.system.url"));
    dataSource.setUsername(environment.getProperty("p4.system.user"));
    dataSource.setPassword(environment.getProperty("p4.system.password"));

    return dataSource;
  }

  @Bean
  public PlatformTransactionManager systemTransactionManager() {
    JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory((systemEntityManagerFactory().getObject()));

    return transactionManager;
  }
}

实体管理器 2

package com.ogl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;

@Configuration
@EnableJpaRepositories(basePackages = "com.ogl.company", entityManagerFactoryRef = "companyEntityManagerFactory", transactionManagerRef = "companyTransactionManager")
public class CompanyJpaConfig {

  private final Environment environment;

  @Autowired
  public CompanyJpaConfig(Environment environment) {
    this.environment = environment;
  }

  @Primary
  @Bean("companyEntityManagerFactory")
  public LocalContainerEntityManagerFactoryBean companyEntityManagerFactory() {
    LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
    entityManagerFactoryBean.setPackagesToScan("com.ogl.company");
    entityManagerFactoryBean.setPersistenceUnitName("company");
    entityManagerFactoryBean.setDataSource(companyDataSource());

    HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
    adapter.setDatabase(Database.POSTGRESQL);
    adapter.setShowSql(true);
    adapter.setGenerateDdl(false);

    entityManagerFactoryBean.setJpaVendorAdapter(adapter);

    return entityManagerFactoryBean;
  }

  @Bean
  DataSource companyDataSource() {
    DriverManagerDataSource dataSource = new DriverManagerDataSource();
    dataSource.setDriverClassName(environment.getProperty("p4.datasource.driver"));
    dataSource.setUrl(environment.getProperty("p4.company.url"));
    dataSource.setUsername(environment.getProperty("p4.company.user"));
    dataSource.setPassword(environment.getProperty("p4.company.password"));

    return dataSource;
  }

  @Primary
  @Bean
  public PlatformTransactionManager companyTransactionManager() {
    JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory((companyEntityManagerFactory().getObject()));

    return transactionManager;
  }
}

注射

package com.ogl;

import org.crygier.graphql.GraphQLExecutor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Configuration
@ComponentScan
public class GraphQLJpaConfig {

  @PersistenceContext(unitName = "company")
  private EntityManager entityManager;

  @Bean
  public GraphQLExecutor graphQLExecutor() {
    return new GraphQLExecutor(entityManager);
  }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.ogl</groupId>
    <artifactId>jpa-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>jpa-demo</name>
    <description>Demo project for JPA</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.graphql-java</groupId>
            <artifactId>graphql-java</artifactId>
            <version>2.3.0</version>
        </dependency>
        <dependency>
            <groupId>com.crygier</groupId>
            <artifactId>graphql-jpa</artifactId>
            <version>0.3</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

Answer 1

您已经定义了两个实体管理器。现在你必须告诉 spring 应该注入哪个。为此，您可以使用 @Qualifier注释：

@PersistenceContext(unitName = "company")
@Qualifier(<Name of the entitimanager you want to use>)
private EntityManager entityManager;

Answer 2

通过使用 @Component 标记我用 EntityManager 注入的类，然后将该类自动连接到使用 GraphQLExecutor 的类中，找到了解决方案：

标记为 @Component 的新类

package p4;

import org.crygier.graphql.GraphQLExecutor;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Component;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Component
public class CompanyGraphQLComponent {

  @PersistenceContext(unitName = "company")
  private EntityManager entityManager;

  public GraphQLExecutor graphQLExecutor() {
    return new GraphQLExecutor(entityManager);
  }
}

自动装配 CompanyGraphQLComponent 类

package p4.rest.controllers;

import core_services.persistence.CompanyContextHolder;
import core_services.records.system.Company;
import graphql.ExecutionResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import p4.CompanyGraphQLComponent;
import p4.records.GraphQLQuery;

@RestController
public class GraphQLController {
  @Autowired
  private CompanyGraphQLComponent companyGraphQLComponent;

  @RequestMapping(value = "/graphql", consumes = MediaType.APPLICATION_JSON_VALUE)
  public ExecutionResult postJson(@RequestBody GraphQLQuery graphQLQuery) {
    return companyGraphQLComponent.graphQLExecutor().execute(graphQLQuery.getQuery(), graphQLQuery.getVariables());
  }
}