Spring Jpa多数据源工程配置过程解析

下面就详细讲解“Spring Jpa多数据源工程配置过程解析”的完整攻略。

一、Spring Jpa多数据源工程配置过程解析

1.1 背景

在实际开发中，有时候我们需要使用多个数据源，分别连接不同数据库进行数据库操作。Spring Jpa框架提供了配置多数据源的方法，本文将详细介绍配置过程。

1.2 配置步骤

1. 添加Maven依赖

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
   <groupId>com.zaxxer</groupId>
   <artifactId>HikariCP</artifactId>
</dependency>

1. 配置数据源

在application.properties文件中配置数据源信息，例如：

# 主数据源：MySQL
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/db1?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=12345

# 从数据源：Oracle
jdbc2.datasource.driverClassName=oracle.jdbc.driver.OracleDriver
jdbc2.datasource.url=jdbc:oracle:thin:@localhost:1521:ORCL
jdbc2.datasource.username=test
jdbc2.datasource.password=12345

1. 配置JPA数据源

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "entityManagerFactory",
        transactionManagerRef = "transactionManager",
        basePackages = {"com.example.dao"}
)
public class JpaConfig {

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

    @Primary
    @Bean(name = "entityManagerFactory")
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(
            EntityManagerFactoryBuilder builder,
            @Qualifier("dataSource") DataSource dataSource) {
        return builder
                .dataSource(dataSource)
                .packages("com.example.entity")
                .persistenceUnit("primaryPersistenceUnit")
                .build();
    }

    @Primary
    @Bean(name = "transactionManager")
    public PlatformTransactionManager transactionManager(
            @Qualifier("entityManagerFactory") EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }
}

1. 配置第二个JPA数据源

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "secondEntityManagerFactory",
        transactionManagerRef = "secondTransactionManager",
        basePackages = {"com.example.dao2"}
)
public class SecondJpaConfig {

    @Bean(name = "secondDataSource")
    @ConfigurationProperties(prefix = "jdbc2.datasource")
    public DataSource secondDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "secondEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory(
            EntityManagerFactoryBuilder builder,
            @Qualifier("secondDataSource") DataSource dataSource) {
        return builder
                .dataSource(dataSource)
                .packages("com.example.entity2")
                .persistenceUnit("secondPersistenceUnit")
                .build();
    }

    @Bean(name = "secondTransactionManager")
    public PlatformTransactionManager secondTransactionManager(
            @Qualifier("secondEntityManagerFactory") EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }
}

1.3 示例说明

下面给出两个示例，分别是从数据库和主数据库的查询。

1. 查询主数据库的用户数据

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public List<User> getList(){
        return userRepository.findAll();
    }
}

1. 查询从数据库的部门数据

@Service
public class DepartmentService {
    @Autowired
    private DepartmentRepository departmentRepository;

    public List<Department> getList(){
        return departmentRepository.findAll();
    }
}

1.4 总结

本文介绍了Spring Jpa多数据源工程配置过程和示例说明，详细讲解了如何配置数据源和JPA数据源，以及如何实现多个数据源的连接与操作。希望本文对读者有所帮助。