Spring boot 2.3 + Spring Data JPA配置多数据源_org.springframework.boot.orm.jpa.entitymanagerfact

项目近期有个需求，要同时连接两个数据库，并且不同环境，数据库种类还不同，我们有两个数据库，其中一个测试环境是oracle，生产环境又是postgre，另一个一直是postgre，调查了网上能搜到很多资料，基本上写法都一致,比如https://blog.csdn.net/itguangit/article/details/78747969，但用在sb 2.3上会发现两个问题，一个是EntityManagerFactoryBuilder在启动时无法自动注入，虽然理论上sb会自动创建其实例，另一个是2.3中jpaProperties已经没有getHibernateProperties这个方法了，花了两天时间，发现一个外国人写的帖子方法是适用于2.3这个版本的，发布时间是去年，比较新，原帖见https://springframework.guru/how-to-configure-multiple-data-sources-in-a-spring-boot-application/ ，但也不是没有问题，需要再改造一下才能完全适应项目开发，下面是改造后的大致的代码

• application.yml

  spring:
    datasource:
      first:
        url: jdbc:postgresql://localhost:5432/sample
        driverClassName: org.postgresql.Driver
        username: postgres
        password: 111
      second:
        url: jdbc:oracle:thin:@//192.168.1.100:1521/orclpdb
        driverClassName: oracle.jdbc.OracleDriver
        username: webdba
        password: 111
    jpa:
      hibernate:
        ddl-auto: none
      show-sql: true
  

   

• 数据源1的配置文件，postgre db
  需要注意的是，这里的每个方法都要使用Primary的注解，只有一个配置文件需要如此 ，这个是sb规定，否则启动时会报错,貌似任意一个都可以指定成这样的，不要被字面意思迷惑

  package com.xxx.config;
   
  import com.zaxxer.hikari.HikariDataSource;
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
  import org.springframework.boot.context.properties.ConfigurationProperties;
  import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
  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.LocalContainerEntityManagerFactoryBean;
  import org.springframework.transaction.PlatformTransactionManager;
  import org.springframework.transaction.annotation.EnableTransactionManagement;
   
  import javax.persistence.EntityManager;
  import javax.persistence.EntityManagerFactory;
  import javax.sql.DataSource;
   
  @Configuration
  @EnableTransactionManagement
  @EnableJpaRepositories(basePackages = "com.xxx.repo.first", //当前数据源对应的repository的包名，每个数据源应该有独立的包
          entityManagerFactoryRef = "firstEntityManagerFactory",
          transactionManagerRef= "firstTransactionManager"
  )
  public class FirstJpaConfig {
      @Bean
      @Primary
      @ConfigurationProperties("spring.datasource.first")
      public DataSourceProperties firstDataSourceProperties() {
          return new DataSourceProperties();
      }
   
      @Bean
      @Primary
      @ConfigurationProperties("spring.datasource.first.configuration")
      public DataSource firstDataSource() {
          return firstDataSourceProperties().initializeDataSourceBuilder()
                  .type(HikariDataSource.class).build();
      }
   
      @Primary
      @Bean(name = "firstEntityManagerFactory")
      public LocalContainerEntityManagerFactoryBean firstEntityManagerFactory(EntityManagerFactoryBuilder builder) {
          return builder
                  .dataSource(firstDataSource())
                  .packages("com.xxx.entity.first") //当前数据源对应的实体的包名，每个数据源应该有独立的包
                  .build();
      }
   
      @Primary
      @Bean
      public PlatformTransactionManager firstTransactionManager(
              final @Qualifier("firstEntityManagerFactory") LocalContainerEntityManagerFactoryBean firstEntityManagerFactory) {
          return new JpaTransactionManager(firstEntityManagerFactory.getObject());
      }
   
      @Primary
      @Bean(name = "firstEntityManager")
  	//这个不是必须，但如果你想在service中注入一个EntityManager用于执行动态jql，这个就是必要的，否则，sb会不知道选择哪个EntityManager实例使用，每个数据源对应一个实例
      public EntityManager entityManager(@Qualifier("firstEntityManagerFactory") EntityManagerFactory factory) {
          return factory.createEntityManager();
      }
  }
   
  

   

• 数据源2的配置文件，oracle db，和第一个高度类似，不解释了

  package com.xxx.config;
   
  import com.zaxxer.hikari.HikariDataSource;
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
  import org.springframework.boot.context.properties.ConfigurationProperties;
  import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
  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.LocalContainerEntityManagerFactoryBean;
  import org.springframework.transaction.PlatformTransactionManager;
  import org.springframework.transaction.annotation.EnableTransactionManagement;
   
  import javax.persistence.EntityManager;
  import javax.persistence.EntityManagerFactory;
  import javax.sql.DataSource;
   
  @Configuration
  @EnableTransactionManagement
  @EnableJpaRepositories(basePackages = "com.xxx.repo.second",
          entityManagerFactoryRef = "secondEntityManagerFactory",
          transactionManagerRef= "secondTransactionManager"
  )
  public class SecondJpaConfig {
      @Bean
      @ConfigurationProperties("spring.datasource.second")
      public DataSourceProperties secondDataSourceProperties() {
          return new DataSourceProperties();
      }
   
      @Bean
      @ConfigurationProperties("spring.datasource.second.configuration")
      public DataSource secondDataSource() {
          return secondDataSourceProperties().initializeDataSourceBuilder()
                  .type(HikariDataSource.class).build();
      }
   
      @Bean(name = "secondEntityManagerFactory")
      public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory(EntityManagerFactoryBuilder builder) {
          return builder
                  .dataSource(secondDataSource())
                  .packages("com.xxx.entity.second")
                  .build();
      }
   
      @Bean
      public PlatformTransactionManager secondTransactionManager(
              final @Qualifier("secondEntityManagerFactory") LocalContainerEntityManagerFactoryBean secondEntityManagerFactory) {
          return new JpaTransactionManager(secondEntityManagerFactory.getObject());
      }
   
      @Bean(name = "secondEntityManager")
      public EntityManager entityManager(@Qualifier("secondEntityManagerFactory") EntityManagerFactory factory) {
          return factory.createEntityManager();
      }
  }
   
  

   

原帖中使用的数据源实现类是dbcp，听说目前性能最好的是Hikari数据源，我就替换了一下，测试运行良好。