Spring boot 2.3 + Spring Data JPA配置多數據源

項目近期有個需求，要同時連接兩個數據庫，並且不同環境，數據庫種類還不同，我們有兩個數據庫，其中一個測試環境是oracle，生產環境又是postgre，另一個一直是postgre，調查了網上能搜到很多資料，基本上寫法都一致,比如https://blog.csdn.net/itguangit/article/details/78747969，但用在sb 2.3上會發現兩個問題，一個是EntityManagerFactoryBuilder在啓動時無法自動注入，雖然理論上sb會自動創建其實例，另一個是2.3中jpaProperties已經沒有getHibernateProperties這個方法了，花了兩天時間，發現一個外國人寫的帖子方法是適用於2.3這個版本的，發佈時間是去年，比較新，原帖見https://springframework.guru/how-to-configure-multiple-data-sources-in-a-spring-boot-application/ ，但也不是沒有問題，需要再改造一下才能完全適應項目開發，下面是改造後的大致的代碼

• 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

   

• 數據源1的配置文件，postgre db
  需要注意的是，這裏的每個方法都要使用Primary的註解，只有一個配置文件需要如此 ，這個是sb規定，否則啓動時會報錯,貌似任意一個都可以指定成這樣的，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", //當前數據源對應的repository的包名，每個數據源應該有獨立的包
          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") //當前數據源對應的實體的包名，每個數據源應該有獨立的包
                  .build();
      }
  
      @Primary
      @Bean
      public PlatformTransactionManager firstTransactionManager(
              final @Qualifier("firstEntityManagerFactory") LocalContainerEntityManagerFactoryBean firstEntityManagerFactory) {
          return new JpaTransactionManager(firstEntityManagerFactory.getObject());
      }
  
      @Primary
      @Bean(name = "firstEntityManager")
  	//這個不是必須，但如果你想在service中注入一個EntityManager用於執行動態jql，這個就是必要的，否則，sb會不知道選擇哪個EntityManager實例使用，每個數據源對應一個實例
      public EntityManager entityManager(@Qualifier("firstEntityManagerFactory") EntityManagerFactory factory) {
          return factory.createEntityManager();
      }
  }
  
  

   

• 數據源2的配置文件，oracle db，和第一個高度類似，不解釋了

  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();
      }
  }
  
  

   

原帖中使用的數據源實現類是dbcp，聽說目前性能最好的是Hikari數據源，我就替換了一下，測試運行良好。