前言
隨著業務量發展，我們通常會進行數據庫拆分或是引入其他數據庫，從而我們需要配置多個數據源，如：user一個庫，business一個庫。那麼接下來我們就要考慮怎麼去在spring boot中實現多個數據源的配置。
源碼下載
實現
- 建表
- 首先是建表語句，我們要建立兩個數據庫，並各庫內新建一張表
- user表
mysql> use `user`； mysql> select * from `user`; +----+-------+----------+ | id | name | password | +----+-------+----------+ | 1 | 用戶A | ****** | +----+-------+----------+ 1 row in set
- business表
mysql> use `business`； mysql> select * from `business`; +----+-------+-------------+ | id | name | description | +----+-------+-------------+ | 1 | 業務A | 業務A描述 | +----+-------+-------------+ 1 row in set
- 接下來我們通過代碼實現對兩個庫內的多張表進行查詢。
- 配置
- 首先，創建一個Spring配置類，定義兩個DataSource用來讀取application.yml中的不同配置。本文中，我們user做為主數據源，主數據源配置為spring.datasource.user開頭的配置，business數據源配置為spring.datasource.business開頭的配置。
@Configuration
public class DataSourceConfig {
@Primary
@Bean(name = "userDataSource")
@Qualifier("userDataSource")
@ConfigurationProperties(prefix = "spring.datasource.user")
public DataSource userDataSource() {
return DataSourceBuilder.create().build();
}
@Bean(name = "businessDataSource")
@Qualifier("businessDataSource")
@ConfigurationProperties(prefix = "spring.datasource.business")
public DataSource businessDataSource() {
return DataSourceBuilder.create().build();
}
}
- 對應的配置文件application.yml如下：
spring: datasource: user: driver-class-name: com.mysql.jdbc.Driver jdbc-url: jdbc:mysql://localhost:3306/user username: root password: 123456 business: driver-class-name: com.mysql.jdbc.Driver jdbc-url: jdbc:mysql://localhost:3306/business username: root password: 123456
- 接下來我們對各數據源進行jpa的配置
- 主數據源User
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
entityManagerFactoryRef = "entityManagerFactoryUser",
transactionManagerRef = "transactionManagerUser",
//設置Repository所在位置
basePackages = {"com.ppc.spring.example.jpamultidatasource.repository.user"})
public class UserConfig {
@Autowired
@Qualifier("userDataSource")
private DataSource userDataSource;
@Autowired
private JpaProperties jpaProperties;
@Autowired
private HibernateProperties hibernateProperties;
@Primary
@Bean(name = "entityManagerUser")
public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
return entityManagerFactoryUser(builder).getObject().createEntityManager();
}
@Primary
@Bean(name = "entityManagerFactoryUser")
public LocalContainerEntityManagerFactoryBean entityManagerFactoryUser(EntityManagerFactoryBuilder builder) {
return builder
.dataSource(userDataSource)
//設置entity所在位置
.packages("com.ppc.spring.example.jpamultidatasource.entity.user")
.persistenceUnit("userPersistenceUnit")
.properties(getVendorProperties())
.build();
}
private Map getVendorProperties() {
return hibernateProperties.determineHibernateProperties(jpaProperties.getProperties(), new HibernateSettings());
}
@Primary
@Bean(name = "transactionManagerUser")
public PlatformTransactionManager transactionManagerUser(EntityManagerFactoryBuilder builder) {
return new JpaTransactionManager(entityManagerFactoryUser(builder).getObject());
}
}
- 其他數據源business
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
entityManagerFactoryRef = "entityManagerFactoryBusiness",
transactionManagerRef = "transactionManagerBusiness",
//設置repository所在位置
basePackages = {"com.ppc.spring.example.jpamultidatasource.repository.business"})
public class BusinessConfig {
@Autowired
@Qualifier("businessDataSource")
private DataSource businessDataSource;
@Autowired
private JpaProperties jpaProperties;
@Autowired
private HibernateProperties hibernateProperties;
@Bean(name = "entityManagerBusiness")
public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
return entityManagerFactoryBusiness(builder).getObject().createEntityManager();
}
@Bean(name = "entityManagerFactoryBusiness")
public LocalContainerEntityManagerFactoryBean entityManagerFactoryBusiness(EntityManagerFactoryBuilder builder) {
return builder
.dataSource(businessDataSource)
.properties(getVendorProperties())
//設置實體類所在位置
.packages("com.ppc.spring.example.jpamultidatasource.entity.business")
.persistenceUnit("businessPersistenceUnit")
.build();
}
private Map getVendorProperties() {
return hibernateProperties.determineHibernateProperties(jpaProperties.getProperties(), new HibernateSettings());
}
@Bean(name = "transactionManagerBusiness")
PlatformTransactionManager transactionManagerBusiness(EntityManagerFactoryBuilder builder) {
return new JpaTransactionManager(entityManagerFactoryBusiness(builder).getObject());
}
}
- 配置中需要注意以下幾點：
- Spring Boot 1.5.x
private Map getVendorProperties() {
return jpaProperties.getHibernateProperties(userDataSource);
}
- Spring Boot 2.0.x
private Map getVendorProperties() {
return jpaProperties.getHibernateProperties(new HibernateSettings());
}
- Spring Boot 2.1.0參見上文代碼，引進了HibernateProperties。同時，在Spring Boot 2.1.0中默認的mysql-connector-java版本為8.0.13，連接低版本mysql配置上比較繁瑣，建議在配置文件中手動指定相應版本，如本文中指定5.1.46這個版本。
runtimeOnly('mysql:mysql-connector-java:5.1.46')
- repository、entity的所在位置，要和實際保存的位置一致。
- 主數據源的一些配置需要添加@Primary作為spring默認的首選項，其他數據源無需添加該註解。
- 通過查看相關源碼我們看到Spring Boot中JpaProperties的代碼一直在調整，這裡我們將properties相關代碼單獨提取出作為一個單獨的方法getVendorProperties展示版本間的區別。其中：
- 查詢
- 完成了所有的配置，接下來我們就可以開始寫個簡單代碼驗證我們配置了
@RestController
@SpringBootApplication
public class JpaMultiDatasourceApplication {
@Autowired
UserRepository userRepository;
@Autowired
BusinessRepository businessRepository;
public static void main(String[] args) {
SpringApplication.run(JpaMultiDatasourceApplication.class, args);
}
@GetMapping("/user/{id}")
public User getUser(@PathVariable Long id) {
return userRepository.findById(id).orElse(null);
}
@GetMapping("/business/{id}")
public Business getBusiness(@PathVariable Long id) {
return businessRepository.findById(id).orElse(null);
}
}
- 我們對外暴露了兩個接口，分別訪問user表、business表確認可以正常獲取數據。查詢結果如下：
請求：http://localhost:8080/user/1
結果：{"id":1,"name":"用戶A","password":"******"}
請求：http://localhost:8080/business/1
結果：{"id":1,"name":"業務A","description":"業務A描述"}
- 就此，我們雙數據源的配置和驗證工作就完成了。
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