前言

隨著業務量增大，可能有些業務不是放在同一個數據庫中，所以系統有需求使用多個數據庫完成業務需求，我們需要配置多個數據源，從而進行操作不同數據庫中數據。

正文

JdbcTemplate 多數據源

配置

需要在 Spring Boot 中配置多個數據庫連接，當然怎么設置連接參數的 key 可以自己決定，

需要注意的是 Spring Boot 2.0 的默認連接池配置參數好像有點問題，由于默認連接池已從 Tomcat 更改為 HikariCP，以前有一個參數 url，已經改成 hikari.jdbcUrl ，不然無法注冊。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

注冊 DataSource

注冊兩個數據源，分別注冊兩個 JdbcTemplate，

@Configuration public class DataSourceConfig {/*** 注冊 data source** @return*/@ConfigurationProperties(prefix = "spring.datasource")@Bean("firstDataSource")@Primary // 有相同實例優先選擇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);} }

測試

@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 支持多數據源

配置

相比使用 jdbcTemplate，需要設置下 JPA 的相關參數即可，沒多大變化：

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 更新表結構# create 每次啟動刪除上次表，再創建表，會造成數據丟失# create-drop： 每次加載hibernate時根據model類生成表，但是sessionFactory一關閉,表就自動刪除。# validate ：每次加載hibernate時，驗證創建數據庫表結構，只會和數據庫中的表進行比較，不會創建新表，但是會插入新值。ddl-auto: updateproperties:hibernate:dialect: org.hibernate.dialect.MySQLDialect

首先一樣的是我們要注冊相應的 DataSource，還需要指定相應的數據源所對應的實體類和數據操作層 Repository的位置：
* firstDataSource

@Configuration @EnableTransactionManagement @EnableJpaRepositories(entityManagerFactoryRef = "firstEntityManagerFactory",transactionManagerRef = "firstTransactionManager",basePackages = "com.wuwii.module.system.dao" // 設置該數據源對應 dao 層所在的位置 ) 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 // 有相同實例優先選擇，相同實例只能設置唯一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") //設置該數據源對應的實體類所在位置.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" // 設置該數據源 dao 層所在的位置 ) 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") //設置該數據源鎖對應的實體類所在的位置.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());}}

測試

@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))));} } 創作挑戰賽新人創作獎勵來咯，堅持創作打卡瓜分現金大獎

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