我已经尝试了小时来实现这一点，看看文档：
https://docs.spring.io/spring-boot/docs/current/reference/html/howto-data-access.html
...各种stackoverflow问题和我能找到的其他东西。但是，这证明是难以捉摸的（阅读，让我想把头撞在墙上）。任何帮助都是如此，所以欢迎！
我需要连接到两个不同的数据库（听起来很简单吗？）并且我有一个使用spring-boot-starter-data-jpa依赖关系的Spring Boot Web应用程序，它使用单个数据源非常好地 / em>的。现在我需要与第二个数据库交谈，但事情并没有奏效。我以为我已经工作了一段时间，但事实证明一切都是在主数据库中进行的。
我目前正试图让这项工作在一个单独的“减少”项目上，试图减少活动部件的数量，但仍然不能正常工作。
我有两个@Configuration类 - 每个数据源一个，这是第一个：
@Configuration
@EnableJpaRepositories(
entityManagerFactoryRef = "firstEntityManagerFactory",
transactionManagerRef = "firstTransactionManager",
basePackages = {"mystuff.jpaexp.jpatest"})
public class DataConfiguration {
@Bean
@Primary
@ConfigurationProperties(prefix = "app.datasource1")
public DataSourceProperties firstDataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@Primary
@ConfigurationProperties("app.datasource1")
public DataSource firstDataSource() {
return firstDataSourceProperties().initializeDataSourceBuilder().
driverClassName("org.postgresql.Driver").
url("jdbc:postgresql://localhost:5432/experiment1").
username("postgres").
password("postgres").
build();
}
@Primary
@Bean
public LocalContainerEntityManagerFactoryBean firstEntityManagerFactory() {
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
vendorAdapter.setGenerateDdl(true);
LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
factory.setJpaVendorAdapter(vendorAdapter);
factory.setPackagesToScan("mystuff.jpaexp.jpatest");
factory.setDataSource(firstDataSource());
factory.setPersistenceUnitName("ds1");
return factory;
}
@Primary
@Bean
public PlatformTransactionManager firstTransactionManager() {
return new JpaTransactionManager();
}
}
这是第二个：
@Configuration
@EnableJpaRepositories(
entityManagerFactoryRef = "secondEntityManagerFactory",
transactionManagerRef = "secondTransactionManager",
basePackages = {"mystuff.jpaexp.jpatest2"})
public class Otherconfiguration {
@Bean
@ConfigurationProperties(prefix = "app.datasource2")
public DataSourceProperties secondDataSourceProperties() {
return new DataSourceProperties();
}
@Bean
@ConfigurationProperties("app.datasource2")
public DataSource secondDataSource() {
return secondDataSourceProperties().initializeDataSourceBuilder().
driverClassName("org.postgresql.Driver").
url("jdbc:postgresql://localhost:5432/experiment2").
username("postgres").
password("postgres").
build();
}
@Bean
public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory() {
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
vendorAdapter.setGenerateDdl(true);
LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
factory.setJpaVendorAdapter(vendorAdapter);
factory.setPackagesToScan("mystuff.jpaexp.jpatest2");
factory.setDataSource(secondDataSource());
factory.setPersistenceUnitName("ds2");
return factory;
}
@Bean
public PlatformTransactionManager secondTransactionManager() {
return new JpaTransactionManager();
}
}
在两个软件包mystuff.jpaexp.jpatest和mystuff.jpaexp.jpatest2的每一个中，我都有一个简单的@Entity和CrudRepository，它们应该分别与第一个和第二个数据源一起使用。
然后我有一个main()来测试：
@SpringBootApplication
@EnableAutoConfiguration(exclude = {WebMvcAutoConfiguration.class})
@ComponentScan("mystuff.jpaexp.*")
public class SpringbootCommandLineApp implements CommandLineRunner {
private final MyRepository myRepository;
private final OtherRepo otherRepo;
@Autowired
public SpringbootCommandLineApp(MyRepository myRepository, OtherRepo otherRepo) {
this.myRepository = myRepository;
this.otherRepo = otherRepo;
}
public static void main(String[] args) {
new SpringApplicationBuilder(SpringbootCommandLineApp.class)
.web(false)
.run(args);
}
@Override
public void run(String... args) throws Exception {
myRepository.save(new MyEntity("Goodbye or hello"));
myRepository.save(new MyEntity("What?"));
myRepository.save(new MyEntity("1,2,3..."));
myRepository.findAll().forEach(System.out::println);
otherRepo.save(new MyEntity2("J Bloggs"));
otherRepo.save(new MyEntity2("A Beecher"));
otherRepo.save(new MyEntity2("C Jee"));
otherRepo.findAll().forEach(x -> {
System.out.println("Name:" + x.getName() + ", ID: " + x.getId());
});
}
}
最后，application.properties中的一些道具：
app.datasource1.driver-class-name=org.postgresql.Driver
app.datasource1.url=jdbc:postgresql://localhost:5432/experiment1
app.datasource1.username=postgres
app.datasource1.password=postgres
app.datasource2.driver-class-name=org.postgresql.Driver
app.datasource2.url=jdbc:postgresql://localhost:5432/experiment2
app.datasource2.username=postgres
app.datasource2.password=postgres
这些完全没效果 - 事情似乎仍由spring.datasource.*配置，显然没用。
最终输出：
2018-05-25 17:04:00.797 WARN 29755 --- [ main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Tomcat.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).
2018-05-25 17:04:00.800 INFO 29755 --- [ main] utoConfigurationReportLoggingInitializer :
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-05-25 17:04:00.803 ERROR 29755 --- [ main] o.s.b.d.LoggingFailureAnalysisReporter :
***************************
APPLICATION FAILED TO START
***************************
Description:
Cannot determine embedded database driver class for database type NONE
Action:
If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).
Process finished with exit code 1
我知道这里有很多代码，对不起，谢谢！
答案 0 :(得分：1)
好吧，花了很长时间，我认为有一些微妙的问题，还有一些可以简化的部分：
pin - 两个数据源都可以使用它DataSourceProperties，而不是@ConfigurationProperties bean DataSourceProperties注释不正确，只用@ComponentScan("mystuff.jpaexp.*")替换它似乎修复了一些bean定义@ComponentScan定义中注入EntityManagerFactor：JpaTransactionManager return new JpaTransactionManager(secondEntityManagerFactory().getObject()); bean，并明确将这些属性拖入JpaProperties VendorAdapter / JpaProperties的变化看起来像这样（JpaProperties独立于供应商但它上面有一个hibernateProperties似乎很奇怪？！）：
VendorAdapter我认为这足以让事情顺利进行。此外，为了使嵌入式H2实例恢复生机，各种属性的永远如此聪明的默认不再有效，所以我还必须明确所有数据库属性：
@Bean
public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory() {
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
vendorAdapter.setGenerateDdl(true);
LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
factory.setJpaVendorAdapter(vendorAdapter);
factory.setPackagesToScan("...entity-package...");
factory.setDataSource(secondDataSource());
Map<String, String> props = new HashMap<>();
props.putAll(secondJpaProperties().getProperties());
props.putAll(secondJpaProperties().getHibernateProperties(secondDataSource()));
factory.setJpaPropertyMap(props);
factory.setPersistenceUnitName("ds2");
return factory;
}
@Bean
@ConfigurationProperties(prefix = "jpa.datsource2")
public JpaProperties secondJpaProperties() {
return new JpaProperties();
}