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-8
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver
second-datasource:
url: jdbc:mysql://localhost:3306/learn1?useSSL=false&allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8
username: root
password: 123457
driver-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")
@Primary
public 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 {
@Autowired
private JdbcTemplate jdbcTemplate;
@Autowired
@Qualifier("secondJdbcTemplate")
private JdbcTemplate jdbcTemplate1;
@Before
public void before() {
jdbcTemplate.update("DELETE FROM employee");
jdbcTemplate1.update("DELETE FROM employee");
}
@Test
public 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-8
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver
second-datasource:
url: jdbc:mysql://localhost:3306/learn1?useSSL=false&allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver
jpa:
show-sql: true
database: mysql
hibernate:
# 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: update
properties:
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 {
@Autowired
private 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 {
@Autowired
private 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 {
@Autowired
private EmployeeDao employeeDao;
@Autowired
private UserDao userDao;
@Before
public void before() {
employeeDao.deleteAll();
userDao.deleteAll();
}
@Test
public 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))));
}
}