Spring Data Jpa 整合篇

application.properties 配置文件

两个数据源配置

# 数据源一
spring.datasource.primary.jdbc-url=jdbc:mysql://localhost:3306/test1
spring.datasource.primary.username=root
spring.datasource.primary.password=123456
spring.datasource.primary.driver-class-name=com.mysql.cj.jdbc.Driver
# 数据源二
spring.datasource.secondary.jdbc-url=jdbc:mysql://localhost:3306/test2
spring.datasource.secondary.username=root
spring.datasource.secondary.password=123456
spring.datasource.secondary.driver-class-name=com.mysql.cj.jdbc.Driver

数据源配置类

@Configuration
public class DataSourceConfiguration {

    @Primary
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.secondary")
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().build();
    }

}

单独配置数据源，对应哪个实体类和Mapper

主数据源

主数据源多了这个注解@Primary

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef="entityManagerFactoryPrimary",
        transactionManagerRef="transactionManagerPrimary",
        basePackages= { "com.didispace.chapter38.p" }) //设置Mapper所在位置
public class PrimaryConfig {

    @Autowired
    @Qualifier("primaryDataSource")
    private DataSource primaryDataSource;

    @Autowired
    private JpaProperties jpaProperties;
    @Autowired
    private HibernateProperties hibernateProperties;

    private Map<String, Object> getVendorProperties() {
        return hibernateProperties.determineHibernateProperties(jpaProperties.getProperties(), new HibernateSettings());
    }

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

    @Primary
    @Bean(name = "entityManagerFactoryPrimary")
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary (EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(primaryDataSource)
                .packages("com.didispace.chapter38.p") //设置实体类所在位置
                .persistenceUnit("primaryPersistenceUnit")
                .properties(getVendorProperties())
                .build();
    }

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

}

第二数据源

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef="entityManagerFactorySecondary",
        transactionManagerRef="transactionManagerSecondary",
        basePackages= { "com.didispace.chapter38.s" }) //设置Mapper所在位置
public class SecondaryConfig {

    @Autowired
    @Qualifier("secondaryDataSource")
    private DataSource secondaryDataSource;

    @Autowired
    private JpaProperties jpaProperties;
    @Autowired
    private HibernateProperties hibernateProperties;

    private Map<String, Object> getVendorProperties() {
        return hibernateProperties.determineHibernateProperties(jpaProperties.getProperties(), new HibernateSettings());
    }

    @Bean(name = "entityManagerSecondary")
    public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
        return entityManagerFactorySecondary(builder).getObject().createEntityManager();
    }

    @Bean(name = "entityManagerFactorySecondary")
    public LocalContainerEntityManagerFactoryBean entityManagerFactorySecondary (EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(secondaryDataSource)
                .packages("com.didispace.chapter38.s") //设置实体类所在位置
                .persistenceUnit("secondaryPersistenceUnit")
                .properties(getVendorProperties())
                .build();
    }

    @Bean(name = "transactionManagerSecondary")
    PlatformTransactionManager transactionManagerSecondary(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(entityManagerFactorySecondary(builder).getObject());
    }

}

注意事项
在使用JPA的时候，需要为不同的数据源创建不同的package来存放对应的Entity和Repository，以便于配置类的分区扫描
类名上的注解@EnableJpaRepositories中指定Repository的所在位置
LocalContainerEntityManagerFactoryBean创建的时候，指定Entity所在的位置
其他主要注意在互相注入时候，不同数据源不同配置的命名，基本就没有什么大问题了

Mabatis 整合篇

application.properties 和数据源配置类同上面的JPA

单独配置数据源不同

主数据源

@Configuration
@MapperScan(
        basePackages = "com.didispace.chapter39.p",
        sqlSessionFactoryRef = "sqlSessionFactoryPrimary",
        sqlSessionTemplateRef = "sqlSessionTemplatePrimary")
public class PrimaryConfig {

    private DataSource primaryDataSource;

    public PrimaryConfig(@Qualifier("primaryDataSource") DataSource primaryDataSource) {
        this.primaryDataSource = primaryDataSource;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactoryPrimary() throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(primaryDataSource);
        return bean.getObject();
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplatePrimary() throws Exception {
        return new SqlSessionTemplate(sqlSessionFactoryPrimary());
    }

}

第二数据源

@Configuration
@MapperScan(
        basePackages = "com.didispace.chapter39.s",
        sqlSessionFactoryRef = "sqlSessionFactorySecondary",
        sqlSessionTemplateRef = "sqlSessionTemplateSecondary")
public class SecondaryConfig {

    private DataSource secondaryDataSource;

    public SecondaryConfig(@Qualifier("secondaryDataSource") DataSource secondaryDataSource) {
        this.secondaryDataSource = secondaryDataSource;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactorySecondary() throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(secondaryDataSource);
        return bean.getObject();
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplateSecondary() throws Exception {
        return new SqlSessionTemplate(sqlSessionFactorySecondary());
    }

}

注意事项
1. 配置类上使用@MapperScan注解来指定当前数据源下定义的Entity和Mapper的包路径；另外需要指定sqlSessionFactory和sqlSessionTemplate，这两个具体实现在该配置类中类中初始化。
2. 配置类的构造函数中，通过@Qualifier注解来指定具体要用哪个数据源，其名字对应在DataSourceConfiguration配置类中的数据源定义的函数名。
3. 配置类中定义SqlSessionFactory和SqlSessionTemplate的实现，注意具体使用的数据源正确（如果使用这里的演示代码，只要第二步没问题就不需要修改）。

小海

Spring Data Jpa 整合篇

Mabatis 整合篇

小海