之前在介绍使用JdbcTemplate和Spring-data-jpa时,都使用了单数据源。在单数据源的情况下,Spring Boot的配置非常简单,只需要在application.properties文件中配置连接参数即可。但是往往随着业务量发展,我们通常会进行数据库拆分或是引入其他数据库,从而我们需要配置多个数据源,下面基于之前的JdbcTemplate和Spring-data-jpa例子分别介绍两种多数据源的配置方式。
创建一个Spring配置类,定义两个DataSource用来读取application.properties中的不同配置。如下例子中,主数据源配置为spring.datasource.primary开头的配置,第二数据源配置为spring.datasource.secondary开头的配置。
@Configuration
public
class
DataSourceConfig {
@Bean
(name =
"primaryDataSource"
)
@Qualifier
(
"primaryDataSource"
)
@ConfigurationProperties
(prefix=
"spring.datasource.primary"
)
public
DataSource primaryDataSource() {
return
DataSourceBuilder.create().build();
}
@Bean
(name =
"secondaryDataSource"
)
@Qualifier
(
"secondaryDataSource"
)
@Primary
@ConfigurationProperties
(prefix=
"spring.datasource.secondary"
)
public
DataSource secondaryDataSource() {
return
DataSourceBuilder.create().build();
}
}
对应的application.properties配置如下:
spring.datasource.primary.url=jdbc:mysql:
//localhost:3306/test1
spring.datasource.primary.username=root
spring.datasource.primary.password=root
spring.datasource.primary.driver-
class
-name=com.mysql.jdbc.Driver
spring.datasource.secondary.url=jdbc:mysql:
//localhost:3306/test2
spring.datasource.secondary.username=root
spring.datasource.secondary.password=root
spring.datasource.secondary.driver-
class
-name=com.mysql.jdbc.Driver
对JdbcTemplate的支持比较简单,只需要为其注入对应的datasource即可,如下例子,在创建JdbcTemplate的时候分别注入名为primaryDataSource和secondaryDataSource的数据源来区分不同的JdbcTemplate。
@Bean
(name =
"primaryJdbcTemplate"
)
public
JdbcTemplate primaryJdbcTemplate(
@Qualifier
(
"primaryDataSource"
) DataSource dataSource) {
return
new
JdbcTemplate(dataSource);
}
@Bean
(name =
"secondaryJdbcTemplate"
)
public
JdbcTemplate secondaryJdbcTemplate(
@Qualifier
(
"secondaryDataSource"
) DataSource dataSource) {
return
new
JdbcTemplate(dataSource);
}
接下来通过测试用例来演示如何使用这两个针对不同数据源的JdbcTemplate。
@RunWith
(SpringJUnit4ClassRunner.
class
)
@SpringApplicationConfiguration
(Application.
class
)
public
class
ApplicationTests {
@Autowired
@Qualifier
(
"primaryJdbcTemplate"
)
protected
JdbcTemplate jdbcTemplate1;
@Autowired
@Qualifier
(
"secondaryJdbcTemplate"
)
protected
JdbcTemplate jdbcTemplate2;
@Before
public
void
setUp() {
jdbcTemplate1.update(
"DELETE FROM USER "
);
jdbcTemplate2.update(
"DELETE FROM USER "
);
}
@Test
public
void
test()
throws
Exception {
// 往第一个数据源中插入两条数据
jdbcTemplate1.update(
"insert into user(id,name,age) values(?, ?, ?)"
,
1
,
"aaa"
,
20
);
jdbcTemplate1.update(
"insert into user(id,name,age) values(?, ?, ?)"
,
2
,
"bbb"
,
30
);
// 往第二个数据源中插入一条数据,若插入的是第一个数据源,则会主键冲突报错
jdbcTemplate2.update(
"insert into user(id,name,age) values(?, ?, ?)"
,
1
,
"aaa"
,
20
);
// 查一下第一个数据源中是否有两条数据,验证插入是否成功
Assert.assertEquals(
"2"
, jdbcTemplate1.queryForObject(
"select count(1) from user"
, String.
class
));
// 查一下第一个数据源中是否有两条数据,验证插入是否成功
Assert.assertEquals(
"1"
, jdbcTemplate2.queryForObject(
"select count(1) from user"
, String.
class
));
}
}
完整示例:Chapter3-2-3
对于数据源的配置可以沿用上例中DataSourceConfig的实现。
新增对第一数据源的JPA配置,注意两处注释的地方,用于指定数据源对应的Entity实体和Repository定义位置,用@Primary区分主数据源。v
新增对第二数据源的JPA配置,内容与第一数据源类似,具体如下:
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories
(
entityManagerFactoryRef=
"entityManagerFactorySecondary"
,
transactionManagerRef=
"transactionManagerSecondary"
,
basePackages= {
"com.didispace.domain.s"
})
//设置Repository所在位置
public
class
SecondaryConfig {
@Autowired
@Qualifier
(
"secondaryDataSource"
)
private
DataSource secondaryDataSource;
@Bean
(name =
"entityManagerSecondary"
)
public
EntityManager entityManager(EntityManagerFactoryBuilder builder) {
return
entityManagerFactorySecondary(builder).getObject().createEntityManager();
}
@Bean
(name =
"entityManagerFactorySecondary"
)
public
LocalContainerEntityManagerFactoryBean entityManagerFactorySecondary (EntityManagerFactoryBuilder builder) {
return
builder
.dataSource(secondaryDataSource)
.properties(getVendorProperties(secondaryDataSource))
.packages(
"com.didispace.domain.s"
)
//设置实体类所在位置
.persistenceUnit(
"secondaryPersistenceUnit"
)
.build();
}
@Autowired
private
JpaProperties jpaProperties;
private
Map<String, String> getVendorProperties(DataSource dataSource) {
return
jpaProperties.getHibernateProperties(dataSource);
}
@Bean
(name =
"transactionManagerSecondary"
)
PlatformTransactionManager transactionManagerSecondary(EntityManagerFactoryBuilder builder) {
return
new
JpaTransactionManager(entityManagerFactorySecondary(builder).getObject());
}
}
完成了以上配置之后,主数据源的实体和数据访问对象位于:com.didispace.domain.p,次数据源的实体和数据访问接口位于:com.didispace.domain.s。
分别在这两个package下创建各自的实体和数据访问接口
主数据源下,创建User实体和对应的Repository接口
@Entity
public
class
User {
@Id
@GeneratedValue
private
Long id;
@Column
(nullable =
false
)
private
String name;
@Column
(nullable =
false
)
private
Integer age;
public
User(){}
public
User(String name, Integer age) {
this
.name = name;
this
.age = age;
}
// 省略getter、setter
}
public
interface
UserRepository
extends
JpaRepository<User, Long> {
}
从数据源下,创建Message实体和对应的Repository接口
@Entity
public
class
Message {
@Id
@GeneratedValue
private
Long id;
@Column
(nullable =
false
)
private
String name;
@Column
(nullable =
false
)
private
String content;
public
Message(){}
public
Message(String name, String content) {
this
.name = name;
this
.content = content;
}
// 省略getter、setter
}
public
interface
MessageRepository
extends
JpaRepository<Message, Long> {
}
接下来通过测试用例来验证使用这两个针对不同数据源的配置进行数据操作。
@RunWith
(SpringJUnit4ClassRunner.
class
)
@SpringApplicationConfiguration
(Application.
class
)
public
class
ApplicationTests {
@Autowired
private
UserRepository userRepository;
@Autowired
private
MessageRepository messageRepository;
@Test
public
void
test()
throws
Exception {
userRepository.save(
new
User(
"aaa"
,
10
));
userRepository.save(
new
User(
"bbb"
,
20
));
userRepository.save(
new
User(
"ccc"
,
30
));
userRepository.save(
new
User(
"ddd"
,
40
));
userRepository.save(
new
User(
"eee"
,
50
));
Assert.assertEquals(
5
, userRepository.findAll().size());
messageRepository.save(
new
Message(
"o1"
,
"aaaaaaaaaa"
));
messageRepository.save(
new
Message(
"o2"
,
"bbbbbbbbbb"
));
messageRepository.save(
new
Message(
"o3"
,
"cccccccccc"
));
Assert.assertEquals(
3
, messageRepository.findAll().size());
}
}
(责任编辑:小恩)