解决spring boot 1.5.4 配置多数据源的问题

spring boot 已经支持多数据源配置了，无需网上好多那些编写什么类的，特别麻烦，看看如下解决方案，官方的，放心！

1.首先定义数据源配置

#=====================multiple database config============================
#ds1
first.datasource.url=jdbc:mysql://localhost/test?characterEncoding=utf8&useSSL=true
first.datasource.username=root
first.datasource.password=123456
first.datasource.driver-class-name=com.mysql.jdbc.Driver
first.datasource.type=org.apache.tomcat.jdbc.pool.DataSource
first.datasource.max-wait=10000
first.datasource.max-active=200
first.datasource.test-on-borrow=true
first.datasource.initial-size=10

#ds2
second.datasource.url=jdbc:mysql://localhost/test2?characterEncoding=utf8&useSSL=true
second.datasource.username=root
second.datasource.password=123456
second.datasource.driver-class-name=com.mysql.jdbc.Driver
second.datasource.type=org.apache.tomcat.jdbc.pool.DataSource
second.datasource.max-wait=10000
second.datasource.max-active=200
second.datasource.test-on-borrow=true
second.datasource.initial-size=10

#=====================jpa config================================
#实体类维护数据库表结构的具体行为：update/create/create-drop/validate/none
spring.jpa.hibernate.ddl-auto=none
#打印sql语句
spring.jpa.show-sql=true
#格式化输出的json字符串
spring.jackson.serialization.indent_output=true

2.配置ds1的相关注入对象和启用jpa支持

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = "com.hdwang.dao.datajpa.firstDs",entityManagerFactoryRef = "firstEntityManagerFactory",transactionManagerRef="firstTransactionManager")
public class FirstDsConfig {

  
  @Bean
  @Primary
  @ConfigurationProperties("first.datasource")
  public DataSourceProperties firstDataSourceProperties() {
    return new DataSourceProperties();
  }

  
  @Bean
  @Primary
  @ConfigurationProperties("first.datasource")
  public DataSource firstDataSource() {
    return firstDataSourceProperties().initializeDataSourceBuilder().build();
  }

  
  @Bean
  @Primary
  public LocalContainerEntityManagerFactoryBean firstEntityManagerFactory(
      EntityManagerFactoryBuilder builder) {
    return builder
 .dataSource(firstDataSource())
 .packages("com.hdwang.entity.dbFirst")
 .persistenceUnit("firstDs")
 .build();
  }

  
  @Bean(name = "firstTransactionManager")
  @Primary
  public PlatformTransactionManager transactionManager(EntityManagerFactory emf){
    JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory(emf);
    return transactionManager;
  }

  @Bean
  @Primary
  public JdbcTemplate jdbcTemplate(){
    return new JdbcTemplate(firstDataSource());
  }

  @Bean
  @Primary
  public TransactionTemplate transactionTemplate(PlatformTransactionManager platformTransactionManager){
    return new TransactionTemplate(platformTransactionManager);
  }
}

相关知识点：

1.使用@Bean可以创建一个bean对象交给spring容器管理

2.@Bean创建的bean对象的名称默认为方法名，也可以指定

3.@Bean方法参数表示，接收一个bean对象，默认按照type类型接收注入的对象，若要修改为byName方式，可以使用@Qualifier注解注入准确的对象

4.@Primary表示该bean为此类型的默认bean，在其他地方引用的时候用@Autowired即可按照类型注入，不受同类型多个对象影响

5.EnableJpaRepositories表示启用spring data jpa的支持，也就是jpa的新使用方式，注意basePackages指的事 @Repository接口的所在包位置，可配置多个

其他注解就不清楚了！

2.配置ds2的相关注入对象和启用jpa支持

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = "com.hdwang.dao.datajpa.secondDs", entityManagerFactoryRef = "secondEntityManagerFactory",transactionManagerRef = "secondTransactionManager")
public class SecondDsConfig {

  @Bean
  @ConfigurationProperties("second.datasource")
  public DataSourceProperties secondDataSourceProperties() {
    return new DataSourceProperties();
  }

  @Bean
  @ConfigurationProperties("second.datasource")
  public DataSource secondDataSource() {
    return secondDataSourceProperties().initializeDataSourceBuilder().build();
  }

  
  @Bean
  public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory(
      EntityManagerFactoryBuilder builder) {
    return builder
 .dataSource(secondDataSource())
 .packages("com.hdwang.entity.dbSecond")
 .persistenceUnit("secondDs")
 .build();
  }

  
  @Bean(name = "secondTransactionManager")
  public PlatformTransactionManager transactionManager(@Qualifier("secondEntityManagerFactory")LocalContainerEntityManagerFactoryBean secondEntityManagerFactory){
    JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory(secondEntityManagerFactory.getObject());
    return transactionManager;
  }

  @Bean(name="jdbcTemplate2")
  public JdbcTemplate jdbcTemplate(){
    return new JdbcTemplate(secondDataSource());
  }

  @Bean(name = "transactionTemplate2")
  public TransactionTemplate transactionTemplate(@Qualifier("secondTransactionManager")PlatformTransactionManager transactionManager){
    return new TransactionTemplate(transactionManager);
  }
}

3.Repository数据持久层

package com.hdwang.dao.datajpa.firstDs;

@Repository
public interface UserRepository extends JpaRepository {
  
  User findByNumber(String number);


  @Modifying
  @Query("delete from User u where u.id = :id")
  void deleteUser(@Param("id")int id);
}

package com.hdwang.dao.datajpa.secondDs;

@Repository
public interface OrderRepository extends JpaRepository {
  
  User findByNumber(String number);


  @Modifying
  @Query("delete from Order o where o.id = :id")
  void deleteUser(@Param("id") int id);
}

上面两个接口分属两个数据源，在@EnableJpaRepositories配置好后，这里就可以正确操作相应的数据源了

4.Service服务层，注意事物（接口我就不贴了）

@Service
@Transactional("firstTransactionManager")
public class UserServiceImpl implements UserService {

  @Autowired
  private UserRepository userRepository;

  @Override
  public User findById(int id) {
    return this.userRepository.findOne(id);
  }

  @Override
  public User findByNumber(String number) {
    return this.userRepository.findByNumber(number);
  }

  @Override
  public List findAllUserByPage(int page,int size) {
    Pageable pageable = new PageRequest(page, size);
    Page users = this.userRepository.findAll(pageable);
    return users.getContent();
  }

  @Override
  public User updateUser(User user,boolean throwEx) {
    User userNew = this.userRepository.save(user);
    if(throwEx){
      throw new RuntimeException("throw a ex");
    }
    return userNew;
  }

  @Override
  public void deleteUser(int id) {
    this.userRepository.deleteUser(id);
  }
}

@Service
@Transactional("secondTransactionManager")
public class OrderServiceImpl implements OrderService {

  @Autowired
  private OrderRepository orderRepository;


  @Override
  public Order findById(int id) {
    return this.orderRepository.findOne(id);
  }

  @Override
  public Order updateOrder(Order order, boolean throwEx) {
    Order orderNew = this.orderRepository.save(order);
    if(throwEx){
      throw new RuntimeException("throw a ex");
    }
    return orderNew;
  }
}

知识扩展

1.如果采用传统jpa方式，@EnableJpaRepositories无需配置，配置了也无影响。实现方式如下：

ds1相关DaoImpl
@PersistenceContext
private EntityManager entityManager;

ds2相关DaoImpl
@PersistenceContext(unitName = "secondDs")
private EntityManager entityManager;

因为ds1的entityManger声明了@Primary，所以无需指明unitName,ds2必须指明。注入了准确的entityManager，就可以直接拿来操作数据库了。service层和上面一样的，@Transactional("xxxManager")指明事物管理器即可！

2.采用jdbcTemplate方式，直接注入到Service层对象即可，so easy!

@Autowired
private JdbcTemplate jdbcTemplate;

@Autowired
private TransactionTemplate transactionTemplate;

@Resource(name="jdbcTemplate2")
private JdbcTemplate jdbcTemplate2;

@Resource(name="transactionTemplate2")
private TransactionTemplate transactionTemplate2;

好了，spring boot 多数据源，完美解决！ 而且三种数据库操作方法均支持，包括事物。已经经过实践证明了！ 这是官方给出的最佳实践，只是官方文档没写细。导致整整坑了我几天。至此，spring boot框架的使用就告一段落了！

以上这篇解决spring boot 1.5.4 配置多数据源的问题就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持考高分网。