那些遇到过的问题

使用 Spring Boot 的 Spring Data JPA 中的多个数据源，

0 java jpa spring-data

当我尝试在 Spring boot 中编写具有两个数据库的应用程序时，Spring Data JPA。它无法创建数据库，这是给定的例外情况。这是我的实现代码

应用类

package com.icarat.eshiksha;
@SpringBootApplication
public class Application  extends SpringBootServletInitializer {
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Application.class);
    }
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}
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application.xml 文件

server.port=8080
server.contextPath=/Eshiksha

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/db_shiksha2
spring.datasource.username=root
spring.datasource.password=*****
spring.datasource.validation-query=select 1

settings.datasource.driver-class-name=com.mysql.jdbc.Driver
settings.datasource.url=jdbc:mysql://127.0.0.1:3306/db_shiksha_settings2
settings.datasource.username=root
settings.datasource.password=*******
settings.datasource.validation-query=select 1
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ShikshaDbConfig 类

package com.icarat.eshiksha.config;
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "shikshaEntityManagerFactory", 
        transactionManagerRef = "shikshaTransactionManager",
        basePackages = { "com.icarat.eshiksha.repository" })
public class ShikshaDbConfig {


    @Autowired
    JpaVendorAdapter jpaVendorAdapter;

    @Autowired
    DataSource dataSource;

    @Bean(name = "shikshaManager")
    public EntityManager shikshaManager() {
        return shikshaEntityManagerFactory().createEntityManager();
    }

    @Primary
    @Bean(name = "shikshaEntityManagerFactory")
    public EntityManagerFactory shikshaEntityManagerFactory() {

          Properties properties = new Properties();
            properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
            properties.setProperty("hibernate.hbm2ddl.auto","update");
            properties.setProperty("hibernate.show_sql", "false");

        LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
        emf.setDataSource(dataSource);
        emf.setJpaVendorAdapter(jpaVendorAdapter);
        emf.setJpaProperties(properties);
        emf.setPackagesToScan("com.icarat.eshiksha.database.entities");
        emf.setPersistenceUnitName("default");   // <- giving 'default' as name
        emf.afterPropertiesSet();
        return emf.getObject();
    }

    @Bean(name = "shikshaTransactionManager")
    public PlatformTransactionManager shikshaTransactionManager() {
        JpaTransactionManager tm = new JpaTransactionManager();
        tm.setEntityManagerFactory(shikshaEntityManagerFactory());
        return tm;
    }   
}
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ShikshaSettingsDbConfig 类

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "settingEntityManagerFactory", 
        transactionManagerRef = "shikshaSettingsTransactionManager",
        basePackages = { "com.icarat.eshiksha.settings.repository" })
public class ShikshaSettingsDbConfig {

     @Autowired
        JpaVendorAdapter jpaVendorAdapter;

        @Value("${settings.datasource.url}")
        private String databaseUrl;

        @Value("${settings.datasource.username}")
        private String username;

        @Value("${settings.datasource.password}")
        private String password;

        @Value("${settings.datasource.driver-class-name}")
        private String driverClassName;



        public DataSource dataSource() {
            DriverManagerDataSource dataSource = new DriverManagerDataSource(databaseUrl, username, password);
            dataSource.setDriverClassName(driverClassName);
            return dataSource;
        }

        @Bean(name = "settingEntityManager")
        public EntityManager settingEntityManager() {
            return settingEntityManagerFactory().createEntityManager();
        }

        @Bean(name = "settingEntityManagerFactory")
        public EntityManagerFactory settingEntityManagerFactory() {
             Properties properties = new Properties();
                properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
                properties.setProperty("hibernate.hbm2ddl.auto","update");
                properties.setProperty("hibernate.show_sql", "false");
             properties.setProperty("hibernate.cache.use_second_level_cache", "true");
            properties.setProperty("hibernate.cache.region.factory_class", "org.hibernate.cache.ehcache.EhCacheRegionFactory");

            LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
            emf.setDataSource(dataSource());
            emf.setJpaVendorAdapter(jpaVendorAdapter);
            emf.setPackagesToScan("com.icarat.eshiksha.settings.database.entites");   // <- package for entities
            emf.setPersistenceUnitName("settingPersistenceUnit");
            emf.setJpaProperties(properties);
            emf.afterPropertiesSet();
            return emf.getObject();
        }

        @Bean(name = "settingsTransactionManager")
        public PlatformTransactionManager settingsTransactionManager() {
            return new JpaTransactionManager(settingEntityManagerFactory());
        }    
}
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组织类

@Entity
@Table(name = "Organization")
public class Organization {

    @Id
@GeneratedValue(strategy=GenerationType.AUTO)   
    @Column(name="orgId")
    private String orgId;

    @Column(name="orgName", unique=true)
    private String orgName;

    @Column(name="orgAddress")
    private String orgAddress;

    @Column(name="pincode")
    private String pincode;


    @Column(name="boardOfEducation")
    private String boardOfEducation;

    @Column(name="recognizedBy")
    private String recognizedBy;

    @Column(name="affiliationNumber")
    private String affiliationNumber;


    @Column(name="faxNumber")
    private String faxNumber;


    @Column(name = "isActive")
    private boolean isActive = true;

    @OneToOne
    private OrganizationAdmin admin;

    @OneToMany(fetch = FetchType.LAZY, mappedBy="org", cascade=CascadeType.REMOVE)
    private List<Branch> branches =new ArrayList<Branch>();
//getter //setter 
}
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组织DAOImpl类

package com.icarat.eshiksha.dao.impl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.stereotype.Service;
import com.icarat.eshiksha.dao.OrganizationDAO;
import com.icarat.eshiksha.database.entities.Organization;
import com.icarat.eshiksha.dto.AddOrgRequestDTO;
import com.icarat.eshiksha.repository.OrganizationRepository;
import com.icarat.eshiksha.util.StringConstants;

@Service
public class OrganizationDAOImpl implements OrganizationDAO {   

    @Autowired
    private OrganizationRepository organizationRepository;  

    @Override
    public String addOrganization(AddOrgRequestDTO request) {   
        Organization org = createHomeEntity(request);
        try {       
            organizationRepository.save(org);       
            return StringConstants.SUCCESS;
        }catch(DataIntegrityViolationException e) {     
            e.printStackTrace();                
            return null;
        } catch(Exception e) {
            e.printStackTrace();        
            return null;
        }
        }   

    private Organization createHomeEntity(final AddOrgRequestDTO request) {
        Organization home = new Organization();
        home.setOrgName(request.getOrgName());  
        home.setOrgAddress(request.getAddress());
        home.setPincode(request.getPincode());
        if(request.getFaxNumber()!=null){
        home.setFaxNumber(request.getFaxNumber());
        }
        if(request.getBoardOfEducation()!=null){
            home.setBoardOfEducation(request.getBoardOfEducation());
            }
            if(request.getRecognizedBy()!=null){
                home.setRecognizedBy(request.getRecognizedBy());
            }
            if(request.getAffiliationNumber()!=null){
                home.setAffiliationNumber(request.getAffiliationNumber());
            }
        return home;
    }
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组织存储库类

package com.icarat.eshiksha.repository;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.icarat.eshiksha.database.entities.Organization;
@Repository
public interface OrganizationRepository extends JpaRepository<Organization, String>{

}
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抛出的异常有

 2017-05-28 16:08:16.061  WARN 4424 --- [           main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'organizationDAOImpl': Unsatisfied dependency expressed through field 'organizationRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'organizationRepository': Cannot resolve reference to bean 'jpaMappingContext' while setting bean property 'mappingContext'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'settingEntityManagerFactory' defined in class path resource [com/icarat/eshiksha/config/ShikshaSettingsDbConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.persistence.EntityManagerFactory]: Factory method 'settingEntityManagerFactory' threw exception; nested exception is java.lang.AbstractMethodError
2017-05-28 16:08:16.070  INFO 4424 --- [           main] utoConfigurationReportLoggingInitializer : 

Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2017-05-28 16:08:16.075 ERROR 4424 --- [           main] o.s.boot.SpringApplication               : Application startup failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'organizationDAOImpl': Unsatisfied dependency expressed through field 'organizationRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'organizationRepository': Cannot resolve reference to bean 'jpaMappingContext' while setting bean property 'mappingContext'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'settingEntityManagerFactory' defined in class path resource [com/icarat/eshiksha/config/ShikshaSettingsDbConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.persistence.EntityManagerFactory]: Factory method 'settingEntityManagerFactory' threw exception; nested exception is java.lang.AbstractMethodError
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.4.RELEASE.jar:1.4.4.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:762) [spring-boot-1.4.4.RELEASE.jar:1.4.4.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:372) [spring-boot-1.4.4.RELEASE.jar:1.4.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-1.4.4.RELEASE.jar:1.4.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1187) [spring-boot-1.4.4.RELEASE.jar:1.4.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1176) [spring-boot-1.4.4.RELEASE.jar:1.4.4.RELEASE]
    at com.icarat.eshiksha.Application.main(Application.java:38) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'organizationRepository': Cannot resolve reference to bean 'jpaMappingContext' while setting bean property 'mappingContext'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'settingEntityManagerFactory' defined in class path resource [com/icarat/eshiksha/config/ShikshaSettingsDbConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.persistence.EntityManagerFactory]: Factory method 'settingEntityManagerFactory' threw exception; nested exception is java.lang.AbstractMethodError
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1531) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1276) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    ... 19 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'settingEntityManagerFactory' defined in class path resource [com/icarat/eshiksha/config/ShikshaSettingsDbConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.persistence.EntityManagerFactory]: Factory method 'settingEntityManagerFactory' threw exception; nested exception is java.lang.AbstractMethodError
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.6.RELEASE.ja

and*_*eim 5

我在这里创建了一个工作POC。README.md 中提供了说明。该解决方案使用 Gradle 进行构建，并使用 Docker 来保留两个 MySQL 实例和一个公开 REST 端点的 SpringBoot 应用程序。

关于您的实施的一些要点：

1.使用唯一的bean名称

您定义了与两个数据源相对应的两个配置。您需要为每个 bean 命名，@Bean("name")并按名称注入它们@Qualifier("name")。

另外，其中一个配置需要用@Primaryelse 注释其 bean，这将不起作用，不要问我为什么。如果您有多个相同类型的 bean 通过类型注入而没有任何进一步的限定，那么接收错误是正常的，但即使注入是用@Qualifier("name"), where"name"是唯一的限定的，似乎也会出现错误。

例如，其中一种配置可能如下所示：

POC MySqlSource1Config.java。

package my.java.spring.jpa.multi.repositories.config;

import my.java.spring.jpa.multi.models.Organization;
import my.java.spring.jpa.multi.repositories.source1.Source1OrganizationRepositoryImpl;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
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.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaDialect;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;

import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;

/**
 * Repository configuration.
 * @EnableJpaRepositories to enable JPA automatic repositories.
 */
@Configuration
@EnableJpaRepositories(
        basePackageClasses = { Source1OrganizationRepositoryImpl.class },
        entityManagerFactoryRef = MySqlSource1Config.EntityManagerFactoryBeanName,
        transactionManagerRef = MySqlSource1Config.TransactionManagerBeanName
)
public class MySqlSource1Config {

    public static final String PrefixName = "source1";
    public static final String DataSourceBeanName = PrefixName + ".data-source";
    public static final String JpaVendorAdapterBeanName = PrefixName + "jpa-vendor-adapter";
    public static final String EntityManagerFactoryBeanName = PrefixName + ".entity-manager-factory";
    public static final String TransactionManagerBeanName = PrefixName + ".transaction-manager";
    public static final String RepositoryBeanName = PrefixName + ".repository";

    @Bean(TransactionManagerBeanName)
    @Primary
    public PlatformTransactionManager transactionManager(
            @Qualifier(EntityManagerFactoryBeanName) EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }

    @Bean(EntityManagerFactoryBeanName)
    @Primary
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(
            @Qualifier(DataSourceBeanName) DataSource dataSource,
            @Qualifier(JpaVendorAdapterBeanName) JpaVendorAdapter vendorAdapter) {

        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        entityManagerFactoryBean.setDataSource(dataSource);
        entityManagerFactoryBean.setJpaVendorAdapter(vendorAdapter);
        entityManagerFactoryBean.setJpaDialect(new HibernateJpaDialect());
        entityManagerFactoryBean.setPackagesToScan(Organization.class.getPackage().getName());
        entityManagerFactoryBean.setPersistenceUnitName("mysqlsource1");
        entityManagerFactoryBean.afterPropertiesSet();

        return entityManagerFactoryBean;
    }

    @Bean(JpaVendorAdapterBeanName)
    @Primary
    @ConfigurationProperties(prefix = "source1.mysql.jpa")
    public JpaVendorAdapter jpaVendorAdapter() {
        return new HibernateJpaVendorAdapter();
    }

    @Bean(DataSourceBeanName)
    @Primary
    @ConfigurationProperties(prefix = "source1.mysql.datasource")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
}
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2.通过bean名称注入bean

因为同一类型有多个 bean 定义，所以您应该通过名称注入 bean @Qualifier()：

@Bean(TransactionManagerBeanName)
@Primary
public PlatformTransactionManager transactionManager(
        @Qualifier(EntityManagerFactoryBeanName) EntityManagerFactory entityManagerFactory) {
    return new JpaTransactionManager(entityManagerFactory);
}
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相反，以下内容是从您的代码中提取的：

@Bean(name = "shikshaTransactionManager")
public PlatformTransactionManager shikshaTransactionManager() {
    JpaTransactionManager tm = new JpaTransactionManager();
    tm.setEntityManagerFactory(shikshaEntityManagerFactory());
    return tm;
}
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这是不行的，因为shikshaEntityManagerFactory()会创建一个新的实例，EntityManagerFactory而不是注入现有的 bean。

3. 无需明确定义EntityManager何时EntityManagerFactory

以下内容摘自您的问题：

@Bean(name = "shikshaManager")
public EntityManager shikshaManager() {
    return shikshaEntityManagerFactory().createEntityManager();
}

@Primary
@Bean(name = "shikshaEntityManagerFactory")
public EntityManagerFactory shikshaEntityManagerFactory() { ... }
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一点是两者都已定义，另一点是，如果您仍然需要EntityManager，那么您应该注入EntityManagerFactorybean，而不是执行shikshaEntityManagerFactory()生成另一个实例的方法调用EntityManagerFactory。

4. 简化配置

您可以使用@ConfigurationProperties而不是@Value将多个配置属性加载到您的 bean 中，例如：

    @Bean(JpaVendorAdapterBeanName)
    @Primary
    @ConfigurationProperties(prefix = "source1.mysql.jpa")
    public JpaVendorAdapter jpaVendorAdapter() {
        return new HibernateJpaVendorAdapter();
    }

    @Bean(DataSourceBeanName)
    @Primary
    @ConfigurationProperties(prefix = "source1.mysql.datasource")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
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然后application.yml两个数据源的结果将如下所示：

source1:
  mysql:
    jpa:
      show-sql: true
      generate-ddl: true
      database: MYSQL
    datasource:
      platform: postgres
      url: jdbc:mysql://localhost:3307/test1
      username: myuser1
      password: mypass1
      driverClassName: com.mysql.cj.jdbc.Driver
source2:
  mysql:
    jpa:
      show-sql: true
      generate-ddl: true
      database: MYSQL
    datasource:
      platform: postgres
      url: jdbc:mysql://localhost:3308/test2
      username: myuser2
      password: mypass2
      driverClassName: com.mysql.cj.jdbc.Driver
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请注意 被jpa加载到JpaVendorAdapter和datasource中DataSource。

5. 保持数据源存储库分离

如果您需要对多个数据源使用相同的实体和存储库，那么您可以保留通用接口OrganizationRepository并拥有单独的接口Source1OrganizationRepository和 IMPL Source1OrganizationRepositoryImpl。

另一方面，如果您有多个数据源不使用的实体和存储库（例如：由源 1 管理的组织和由源 2 管理的用户），那么将会有由不同源管理的不同包，但不需要通用的包界面。

这允许将存储库 bean 命名为：

@Repository(MySqlSource1Config.RepositoryBeanName)
public interface Source1OrganizationRepository extends OrganizationRepository {
}
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为了与其他数据源存储库区分开来。

这些已配置，就像您已经在配置中使用它们一样（请注意basePackageClasses）：

@Configuration
@EnableJpaRepositories(
        basePackageClasses = { Source1OrganizationRepositoryImpl.class },
        entityManagerFactoryRef = MySqlSource1Config.EntityManagerFactoryBeanName,
        transactionManagerRef = MySqlSource1Config.TransactionManagerBeanName
)
public class MySqlSource1Config { ... }
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然后，可以将这些存储库进一步注入到控制器、服务或任何其他组件中，例如：

@RestController
@RequestMapping("/v1/organization")
public class OrganizationController {

    private final OrganizationRepository organizationRepositoryFromSource1;
    private final OrganizationRepository organizationRepositoryFromSource2;

    @Autowired
    public OrganizationController(
            @Qualifier(MySqlSource1Config.RepositoryBeanName) OrganizationRepository organizationRepositoryFromSource1,
            @Qualifier(MySqlSource2Config.RepositoryBeanName) OrganizationRepository organizationRepositoryFromSource2) {

        this.organizationRepositoryFromSource1 = organizationRepositoryFromSource1;
        this.organizationRepositoryFromSource2 = organizationRepositoryFromSource2;
    }

...
}
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相同的实体可以与多个数据源一起使用，并由 加载EntityManager，并且可以在 内进行配置EntityManagerFactory：

@Bean(EntityManagerFactoryBeanName)
@Primary
public LocalContainerEntityManagerFactoryBean entityManagerFactory(
        @Qualifier(DataSourceBeanName) DataSource dataSource,
        @Qualifier(JpaVendorAdapterBeanName) JpaVendorAdapter vendorAdapter) {

...
entityManagerFactoryBean.setPackagesToScan(Organization.class.getPackage().getName());
...

}
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注意：在application.yml中application-docker.yml我使用了source1.mysql.jpa.generate-ddl: true. 这意味着与所找到的实体对应的表和模式EntityManager将在 MySQL 数据库中自动创建。如果您通过其他方式管理数据库架构，例如创建脚本并使用FlyWay或迁移它们Liquidbase，那么您可能需要将该选项转为false以便采用您自己的流程。

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