springboot +jpa配置双数据源

业务需求需要在一个项目里配置两个数据源。项目使用的是springboot，springDataJpa。研究一下目前可以正常运行，还没有出现什么bug。

一。配置文件中配置多数据源

spring:
  devtools:
    restart:
      enabled: false
  http:
    multipart:
      max-file-size: 1000Mb
      max-request-size: 1000Mb        
  # mysql DATABASE CONFIG
  datasource:
    name: dataSource
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    master:
        url: jdbc:mysql://127.0.0.1:3306/dataSource1?useUnicode=true&characterEncoding=utf-8&autoReconnect=true&allowMultiQueries=true
        username: root
        password: 123456
        
    slave:
        url: jdbc:mysql://127.0.0.1:3306/dataSource2?useUnicode=true&characterEncoding=utf-8&autoReconnect=true&allowMultiQueries=true
        username: root
        password: 123456
        

二。数据库连接池配置

连接池使用的阿里的DRUID，需要根据第一步配置的数据源生成主从配置。

/**
 * druid 配置多数据源
 *
 */
@Configuration
public class DruidConfig
{

    /**
     * 主DataSource 配置
     */
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.master")
    @Bean(name = "primaryDruidDataSource")
    public DataSource primaryDruidDataSource(Environment environment) {
        return DruidDataSourceBuilder.create().build(environment, "spring.datasource.master.");
    }


    /**
     * 从DataSource 配置
     */
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    @Bean(name = "slaveDruidDataSource")
    public DataSource slaveDruidDataSource(Environment environment) {
        return DruidDataSourceBuilder.create().build(environment, "spring.datasource.slave.");
    }

}

注：Environment是spring3.1提供的新的属性管理API.可以根据环境得到相应数据。

三。主从数据源的配置

数据源的配置采用注解的方式。

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "entityManagerFactoryPrimary",
        transactionManagerRef = "transactionManagerPrimary",
        basePackages = {"com.test1.repository"},
        repositoryBaseClass = BaseSimpleRepository.class,
        repositoryFactoryBeanClass = RepositoryFactoryBean.class) //设置Repository所在位置
public class PrimaryConfig {

    @Resource(name = "primaryDruidDataSource")
    private DataSource primaryDruidDataSource;

    @Autowired
    private JpaProperties jpaProperties;

    @Primary
    @Bean(name = "entityManagerFactoryPrimary")
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary(EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(primaryDruidDataSource)
                .properties(getVendorProperties(primaryDruidDataSource))
                .packages("com.test1.entity") //设置实体类所在位置
                .persistenceUnit("primaryPersistenceUnit")
                .build();
    }

    @Primary
    @Bean(name = "entityManagerPrimary")
    public EntityManager entityManagerPrimary(EntityManagerFactoryBuilder builder) {
        return entityManagerFactoryPrimary(builder).getObject().createEntityManager();
    }

    private Map<String, String> getVendorProperties(DataSource dataSource) {
        return jpaProperties.getHibernateProperties(dataSource);
    }

    @Primary
    @Bean(name = "transactionManagerPrimary")
    public PlatformTransactionManager transactionManagerPrimary(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(entityManagerFactoryPrimary(builder).getObject());
    }

}

注:@Primary默认使用DataSource1为默认数据源。

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "entityManagerFactorySlave",
        transactionManagerRef = "transactionManagerSlave",
        basePackages = {"com.test1.repository.test2"},
        repositoryBaseClass = BaseSimpleRepository.class,
        repositoryFactoryBeanClass = RepositoryFactoryBean.class) //设置Repository所在位置
public class SlaveConfig {

    @Resource(name = "slaveDruidDataSource")
    private DataSource slaveDruidDataSource;

    @Autowired
    private JpaProperties jpaProperties;

    @Bean(name = "entityManagerFactorySlave")
    public LocalContainerEntityManagerFactoryBean entityManagerFactorySlave(EntityManagerFactoryBuilder builder) {
        LocalContainerEntityManagerFactoryBean slavePersistenceUnit = builder
                .dataSource(slaveDruidDataSource)
                .properties(getVendorProperties(slaveDruidDataSource))
                .packages("com.test1.entity.test2") //设置实体类所在位置
                .persistenceUnit("slavePersistenceUnit")
                .build();
        slavePersistenceUnit.getJpaPropertyMap().remove("hibernate.hbm2ddl.auto");
        return slavePersistenceUnit;
    }

    @Bean(name = "entityManagerSlave")
    public EntityManager entityManagerSlave(EntityManagerFactoryBuilder builder) {
        return entityManagerFactorySlave(builder).getObject().createEntityManager();
    }

    private Map<String, String> getVendorProperties(DataSource dataSource) {
        return jpaProperties.getHibernateProperties(dataSource);
    }

    @Bean(name = "transactionManagerSlave")
    public PlatformTransactionManager transactionManagerSlave(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(entityManagerFactorySlave(builder).getObject());
    }

}

这样就配置好了。如果是在旧项目中添加数据源，要把原来jpa的配置删除掉。