在单数据源的情况下，Spring Boot的配置非常简单，只需要在application.yml中配置连接参数即可。但是随着业务的复杂性提升，通常会对数据库进行拆分或是引入其它数据库，因此需要配置多个数据源。
多数据源配置
我们需要创建一个Spring配置类，定义两个DataSource来读取application.yml中的不同配置。
spring:
datasource:
primary:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/dbtest?useUnicode=true&characterEncoding=utf8&useSSL=true
username: root
password: dbpass
secondary:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/dbtest2?useUnicode=true&characterEncoding=utf8&useSSL=true
username: root
password: dbpass
JdbcTemplate支持
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);
}
Spring-data-jpa支持
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。
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
entityManagerFactoryRef="entityManagerFactoryPrimary",
transactionManagerRef="transactionManagerPrimary",
basePackages= { "com.didispace.domain.p" }) //设置Repository所在位置
public class PrimaryConfig {
@Autowired @Qualifier("primaryDataSource")
private DataSource primaryDataSource;
@Primary
@Bean(name = "entityManagerPrimary")
public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
return entityManagerFactoryPrimary(builder).getObject().createEntityManager();
}
@Primary
@Bean(name = "entityManagerFactoryPrimary")
public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary (EntityManagerFactoryBuilder builder) {
return builder
.dataSource(primaryDataSource)
.properties(getVendorProperties(primaryDataSource))
.packages("com.didispace.domain.p") //设置实体类所在位置
.persistenceUnit("primaryPersistenceUnit")
.build();
}
@Autowired
private JpaProperties jpaProperties;
private Map<String, String> getVendorProperties(DataSource dataSource) {
return jpaProperties.getHibernateProperties(dataSource);
}
@Primary
@Bean(name = "transactionManagerPrimary")
public PlatformTransactionManager transactionManagerPrimary(EntityManagerFactoryBuilder builder) {
return new JpaTransactionManager(entityManagerFactoryPrimary(builder).getObject());
}
}
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> {
}
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