学习Spring Boot：（二十四）多数据源配置与使用

前言

随着业务量增大，可能有些业务不是放在同一个数据库中，所以系统有需求使用多个数据库完成业务需求，我们需要配置多个数据源，从而进行操作不同数据库中数据。

正文

JdbcTemplate 多数据源

配置

需要在 Spring Boot 中配置多个数据库连接，当然怎么设置连接参数的 key 可以自己决定，

需要注意的是 Spring Boot 2.0 的默认连接池配置参数好像有点问题，由于默认连接池已从 Tomcat 更改为 HikariCP，以前有一个参数 url，已经改成 hikari.jdbcUrl ，不然无法注册。我下面使用的版本是 1.5.9。

server:port: 8022
spring:datasource:url: jdbc:mysql://localhost:3306/learn?useSSL=false&allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8username: rootpassword: 123456driver-class-name: com.mysql.jdbc.Driversecond-datasource:url: jdbc:mysql://localhost:3306/learn1?useSSL=false&allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8username: rootpassword: 123457driver-class-name: com.mysql.jdbc.Driver

注册 DataSource

注册两个数据源，分别注册两个 JdbcTemplate，

@Configuration
public class DataSourceConfig {/*** 注册 data source** @return*/@ConfigurationProperties(prefix = "spring.datasource")@Bean("firstDataSource")@Primary // 有相同实例优先选择public DataSource firstDataSource() {return DataSourceBuilder.create().build();}@ConfigurationProperties(prefix = "spring.second-datasource")@Bean("secondDataSource")public DataSource secondDataSource() {return DataSourceBuilder.create().build();}@Bean("firstJdbcTemplate")@Primarypublic JdbcTemplate firstJdbcTemplate(DataSource dataSource) {return new JdbcTemplate(dataSource);}@Bean("secondJdbcTemplate")public JdbcTemplate secondJdbcTemplate(@Qualifier("secondDataSource") DataSource dataSource) {return new JdbcTemplate(dataSource);}
}

测试

@SpringBootTest
@RunWith(SpringRunner.class)
public class TestJDBC {@Autowiredprivate JdbcTemplate jdbcTemplate;@Autowired@Qualifier("secondJdbcTemplate")private JdbcTemplate jdbcTemplate1;@Beforepublic void before() {jdbcTemplate.update("DELETE FROM employee");jdbcTemplate1.update("DELETE FROM employee");}@Testpublic void testJDBC() {jdbcTemplate.update("insert into employee(id,name,age) VALUES (1, 'wuwii', 24)");jdbcTemplate1.update("insert into employee(id,name,age) VALUES (1, 'kronchan', 23)");Assert.assertThat("wuwii", Matchers.equalTo(jdbcTemplate.queryForObject("SELECT name FROM employee WHERE id=1", String.class)));Assert.assertThat("kronchan", Matchers.equalTo(jdbcTemplate1.queryForObject("SELECT name FROM employee WHERE id=1", String.class)));}
}

使用 JPA 支持多数据源

配置

相比使用 jdbcTemplate，需要设置下 JPA 的相关参数即可，没多大变化：

server:port: 8022
spring:datasource:url: jdbc:mysql://localhost:3306/learn?useSSL=false&allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8username: rootpassword: 123456driver-class-name: com.mysql.jdbc.Driversecond-datasource:url: jdbc:mysql://localhost:3306/learn1?useSSL=false&allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8username: rootpassword: 123456driver-class-name: com.mysql.jdbc.Driverjpa:show-sql: truedatabase: mysqlhibernate:# update 更新表结构# create 每次启动删除上次表，再创建表，会造成数据丢失# create-drop： 每次加载hibernate时根据model类生成表，但是sessionFactory一关闭,表就自动删除。# validate ：每次加载hibernate时，验证创建数据库表结构，只会和数据库中的表进行比较，不会创建新表，但是会插入新值。ddl-auto: updateproperties:hibernate:dialect: org.hibernate.dialect.MySQLDialect

首先一样的是我们要注册相应的 DataSource，还需要指定相应的数据源所对应的实体类和数据操作层 Repository的位置：
* firstDataSource

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(entityManagerFactoryRef = "firstEntityManagerFactory",transactionManagerRef = "firstTransactionManager",basePackages = "com.wuwii.module.system.dao" // 设置该数据源对应 dao 层所在的位置
)
public class FirstDataSourceConfig {@Autowiredprivate JpaProperties jpaProperties;@Primary@Bean(name = "firstEntityManager")public EntityManager entityManager(EntityManagerFactoryBuilder builder) {return entityManagerFactoryPrimary(builder).getObject().createEntityManager();}@ConfigurationProperties(prefix = "spring.datasource")@Bean("firstDataSource")@Primary // 有相同实例优先选择，相同实例只能设置唯一public DataSource firstDataSource() {return DataSourceBuilder.create().build();}@Primary@Bean(name = "firstEntityManagerFactory")public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary (EntityManagerFactoryBuilder builder) {return builder.dataSource(firstDataSource()).properties(getVendorProperties(firstDataSource())).packages("com.wuwii.module.system.entity") //设置该数据源对应的实体类所在位置.persistenceUnit("firstPersistenceUnit").build();}private Map<String, String> getVendorProperties(DataSource dataSource) {return jpaProperties.getHibernateProperties(dataSource);}@Primary@Bean(name = "firstTransactionManager")public PlatformTransactionManager transactionManagerPrimary(EntityManagerFactoryBuilder builder) {return new JpaTransactionManager(entityManagerFactoryPrimary(builder).getObject());}}

secondDataSource：

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(entityManagerFactoryRef = "secondEntityManagerFactory",transactionManagerRef = "secondTransactionManager",basePackages = "com.wuwii.module.user.dao" // 设置该数据源 dao 层所在的位置
)
public class SecondDataSourceConfig {@Autowiredprivate JpaProperties jpaProperties;@Bean(name = "secondEntityManager")public EntityManager entityManager(EntityManagerFactoryBuilder builder) {return entityManagerFactoryPrimary(builder).getObject().createEntityManager();}@ConfigurationProperties(prefix = "spring.second-datasource")@Bean("secondDataSource")public DataSource secondDataSource() {return DataSourceBuilder.create().build();}@Bean(name = "secondEntityManagerFactory")public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary (EntityManagerFactoryBuilder builder) {return builder.dataSource(secondDataSource()).properties(getVendorProperties(secondDataSource())).packages("com.wuwii.module.user.entity") //设置该数据源锁对应的实体类所在的位置.persistenceUnit("secondPersistenceUnit").build();}private Map<String, String> getVendorProperties(DataSource dataSource) {return jpaProperties.getHibernateProperties(dataSource);}@Bean(name = "secondTransactionManager")public PlatformTransactionManager transactionManagerPrimary(EntityManagerFactoryBuilder builder) {return new JpaTransactionManager(entityManagerFactoryPrimary(builder).getObject());}}

测试

@SpringBootTest
@RunWith(SpringRunner.class)
public class TestDemo {@Autowiredprivate EmployeeDao employeeDao;@Autowiredprivate UserDao userDao;@Beforepublic void before() {employeeDao.deleteAll();userDao.deleteAll();}@Testpublic void test() {Employee employee = new Employee(null, "wuwii", 24);employeeDao.save(employee);User user = new User(null, "KronChan", 24);userDao.save(user);Assert.assertThat(employee, Matchers.equalTo(employeeDao.findOne(Example.of(employee))));Assert.assertThat(user, Matchers.equalTo(userDao.findOne(Example.of(user))));}
}