在复杂的企业应用中，多数据源管理是常见需求。本文将介绍如何基于Spring Boot实现优雅的动态数据源切换方案，通过自定义注解和AOP实现透明化切换。

核心设计思路

通过三层结构实现数据源动态路由：
1. 注解层：声明式标记数据源
2. 路由层：基于ThreadLocal的上下文管理
3. 切面层：在方法执行前后自动切换数据源

核心实现代码

1. 数据源注解定义

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {String name() default ""; // 数据源名称
}

2. 动态数据源上下文

public class DynamicDataSourceContext extends AbstractRoutingDataSource {private static String DEFAULT_DATASOURCE_NAME;private static final ThreadLocal<String> CONTEXT_HOLDER = new ThreadLocal<>();public DynamicDataSourceContext(String defaultDataSourceName, Map<Object, Object> targetDataSources) {super.setDefaultTargetDataSource(targetDataSources.get(defaultDataSourceName));super.setTargetDataSources(targetDataSources);DEFAULT_DATASOURCE_NAME = defaultDataSourceName;super.afterPropertiesSet(); // 关键初始化}@Overrideprotected Object determineCurrentLookupKey() {return getDataSourceKey(); // 获取当前数据源标识}// 数据源操作工具方法public static void setDataSourceKey(String key) {CONTEXT_HOLDER.set(key);}public static String getDataSourceKey() {return CONTEXT_HOLDER.get(); }public static void clearDataSourceKey() {CONTEXT_HOLDER.remove(); }public static String getDefaultDataSourceName() {return DEFAULT_DATASOURCE_NAME;}
}

3. AOP切面实现

@Aspect
@Component
@Order(-1) // 确保在事务切面前执行
public class DataSourceAspect {@Around("@within(DataSource) || @annotation(DataSource)")public Object around(ProceedingJoinPoint point) throws Throwable {MethodSignature signature = (MethodSignature) point.getSignature();Method method = signature.getMethod();// 优先级：方法注解 > 类注解 > 默认数据源DataSource methodAnno = method.getAnnotation(DataSource.class);DataSource classAnno = method.getDeclaringClass().getAnnotation(DataSource.class);String dataSource = DynamicDataSourceContext.getDefaultDataSourceName();if (methodAnno != null && StringUtils.hasText(methodAnno.name())) {dataSource = methodAnno.name();} else if (classAnno != null && StringUtils.hasText(classAnno.name())) {dataSource = classAnno.name();}try {DynamicDataSourceContext.setDataSourceKey(dataSource);return point.proceed(); // 执行目标方法} finally {DynamicDataSourceContext.clearDataSourceKey(); // 清理数据源标识}}
}

自动配置

在`src/main/resources/META-INF/spring`目录下创建文件：
org.springframework.boot.autoconfigure.AutoConfiguration.imports

com.test.datasourcestater.aspect.DataSourceAspect

使用示例

1、新增动态切换数据源定义

@Configuration
@Component
public class DynamicDataSourceConfig {//默认数据源定义@Resource(name = "defaultDataSource")private DataSource defaultDataSource;//其他数据源定义@Resource(name = "testDataSource")private DataSource testDataSource;@Bean("dynamicDataSource")@Primarypublic DynamicDataSourceContext dynamicDataSource() {Map<Object, Object> targetDataSources = new HashMap<>();//添加默认数据源和其他数据源targetDataSources.put("default",defaultDataSource);targetDataSources.put("testDataSource",testDataSource);return new DynamicDataSourceContext("default", targetDataSources);}@Bean("dataSourceTransactionManager")public DataSourceTransactionManager dataSourceTransactionManager(@Qualifier("dynamicDataSource") DataSource dataSource){DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();dataSourceTransactionManager.setDataSource(dataSource);return dataSourceTransactionManager;}@Bean("jdbcTemplate")public JdbcTemplate jdbcTemplate(@Qualifier("dynamicDataSource") DataSource dataSource){JdbcTemplate jdbcTemplate = new JdbcTemplate();jdbcTemplate.setDataSource(dataSource);return  jdbcTemplate;}
}

其他数据源定义：

@Configuration
@ConfigurationProperties(prefix = "xxx")
@Data
public class TestDataSourceConfig {private String driverClassName;private String url;private String username;private String password;private String validationQuery;private int initialSize;private int maxActive;private int maxIdle;private int minIdle;@Bean("testDataSource")public BasicDataSourceDecrypt basicDataSourceDecrypt(){BasicDataSourceDecrypt basicDataSourceDecrypt = new BasicDataSourceDecrypt();basicDataSourceDecrypt.setUsername(username);basicDataSourceDecrypt.setPassword(password);basicDataSourceDecrypt.setDriverClassName(driverClassName);basicDataSourceDecrypt.setPoolName("xxx");// 数据库连接地址basicDataSourceDecrypt.setJdbcUrl(url);//  最小空闲连接，默认值10，小于0或大于maximum-pool-size，都会重置为maximum-pool-sizebasicDataSourceDecrypt.setMinimumIdle(minIdle);// 最大连接数，小于等于0会被重置为默认值10；大于零小于1会被重置为minimum-idle的值basicDataSourceDecrypt.setMaximumPoolSize(maxActive);// 空闲连接超时时间，默认值600000（10分钟），大于等于max-lifetime且max-lifetime>0，会被重置为0；不等于0且小于10秒，会被重置为10秒。basicDataSourceDecrypt.setIdleTimeout(30000);// 连接最大存活时间，不等于0且小于30秒，会被重置为默认值30分钟.设置应该比mysql设置的超时时间短basicDataSourceDecrypt.setMaxLifetime(360000L);// 连接超时时间：毫秒，小于250毫秒，否则被重置为默认值30秒basicDataSourceDecrypt.setConnectionTimeout(500);// 用于测试连接是否可用的查询语句basicDataSourceDecrypt.setConnectionTestQuery(validationQuery);return basicDataSourceDecrypt;}
}

2、修改原始的DataSourceConfig为默认数据源

将datasource bean 定义名称改成@Bean("defaultDataSource")
将@Qualifier("dataSource")改成@Qualifier("dynamicDataSource") 参考代码，如下:

@Configuration
@ConfigurationProperties(prefix = "xxx")
@Data
public class DataSourceConfig {private String driverClassName;private String url;private String username;private String password;private String validationQuery;private int initialSize;private int maxActive;private int maxIdle;private int minIdle;@Bean("defaultDataSource")public BasicDataSourceDecrypt basicDataSourceDecrypt(){BasicDataSourceDecrypt basicDataSourceDecrypt = new BasicDataSourceDecrypt();basicDataSourceDecrypt.setDriverClassName(driverClassName);basicDataSourceDecrypt.setUsername(username);basicDataSourceDecrypt.setPassword(password);basicDataSourceDecrypt.setPoolName("xx");// 数据库连接地址basicDataSourceDecrypt.setJdbcUrl(url);//  最小空闲连接，默认值10，小于0或大于maximum-pool-size，都会重置为maximum-pool-sizebasicDataSourceDecrypt.setMinimumIdle(minIdle);// 最大连接数，小于等于0会被重置为默认值10；大于零小于1会被重置为minimum-idle的值basicDataSourceDecrypt.setMaximumPoolSize(maxActive);// 空闲连接超时时间，默认值600000（10分钟），大于等于max-lifetime且max-lifetime>0，会被重置为0；不等于0且小于10秒，会被重置为10秒。basicDataSourceDecrypt.setIdleTimeout(60000);// 连接最大存活时间，不等于0且小于30秒，会被重置为默认值30分钟.设置应该比mysql设置的超时时间短basicDataSourceDecrypt.setMaxLifetime(600000);// 连接超时时间：毫秒，小于250毫秒，否则被重置为默认值30秒basicDataSourceDecrypt.setConnectionTimeout(30000);// 用于测试连接是否可用的查询语句basicDataSourceDecrypt.setConnectionTestQuery(validationQuery);return basicDataSourceDecrypt;}@Bean("messageResource")public ResourceBundleMessageSource resourceBundleMessageSource(){ResourceBundleMessageSource messageResource = new ResourceBundleMessageSource();messageResource.setDefaultEncoding("UTF-8");messageResource.setCacheSeconds(0);return  messageResource;}@Bean("dataSourceTransactionManager")public DataSourceTransactionManager dataSourceTransactionManager(@Qualifier("dynamicDataSource") BasicDataSourceDecrypt dataSource){DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();dataSourceTransactionManager.setDataSource(dataSource);return dataSourceTransactionManager;}@Bean("jdbcTemplate")public JdbcTemplate jdbcTemplate(@Qualifier("dynamicDataSource") BasicDataSourceDecrypt dataSource){JdbcTemplate jdbcTemplate = new JdbcTemplate();jdbcTemplate.setDataSource(dataSource);return  jdbcTemplate;}}

3、修改mybatisPlusConfig配置

dataSource注入，改成注入@Resource(name="dynamicDataSource")

@Configuration
@EnableTransactionManagement
public class MybatisPlusConfig {@Resource(name="dynamicDataSource")private DataSource dataSource;@Autowiredprivate MybatisPlusProperties properties;@Autowiredprivate ResourceLoader resourceLoader = new DefaultResourceLoader();@Autowired(required = false)private DatabaseIdProvider databaseIdProvider;@Beanpublic DatabaseIdProvider getDatabaseIdProvider() {DatabaseIdProvider databaseIdProvider = new VendorDatabaseIdProvider();Properties properties = new Properties();databaseIdProvider.setProperties(properties);return databaseIdProvider;}/***    mybatis-plus分页插件*/@Bean("paginationInterceptor")public PaginationInnerInterceptor paginationInterceptor(@Value("${database.type:mysql}") String databaseType) {PaginationInnerInterceptor page = new PaginationInnerInterceptor();page.setDbType(DbType.getDbType(databaseType));return page;}@Bean("optimisticLockerInterceptor")public OptimisticLockerInnerInterceptor optimisticLockerInterceptor() {return new OptimisticLockerInnerInterceptor();}@Bean("mybatisPlusInterceptor")public MybatisPlusInterceptor mybatisPlusInterceptor(@Qualifier("paginationInterceptor") PaginationInnerInterceptor paginationInterceptor,@Qualifier("optimisticLockerInterceptor") OptimisticLockerInnerInterceptor optimisticLockerInterceptor){MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();mybatisPlusInterceptor.addInnerInterceptor(paginationInterceptor);mybatisPlusInterceptor.addInnerInterceptor(optimisticLockerInterceptor);return mybatisPlusInterceptor;}/*** 这里全部使用mybatis-autoconfigure 已经自动加载的资源。不手动指定* 配置文件和mybatis-boot的配置文件同步* @return*/@Bean("sqlSessionFactory")public MybatisSqlSessionFactoryBean mybatisSqlSessionFactoryBean(@Qualifier("globalConfiguration") GlobalConfig globalConfig,@Qualifier("mybatisPlusInterceptor") MybatisPlusInterceptor mybatisPlusInterceptor) {MybatisSqlSessionFactoryBean mybatisPlus = new MybatisSqlSessionFactoryBean();mybatisPlus.setDataSource(dataSource);mybatisPlus.setVfs(SpringBootVFS.class);if (StringUtils.hasText(this.properties.getConfigLocation())) {mybatisPlus.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfigLocation()));}mybatisPlus.setConfiguration(properties.getConfiguration());mybatisPlus.setPlugins(mybatisPlusInterceptor);mybatisPlus.setGlobalConfig(globalConfig);MybatisConfiguration mc = new MybatisConfiguration();mc.setDefaultScriptingLanguage(MybatisXMLLanguageDriver.class);mybatisPlus.setConfiguration(mc);if (this.databaseIdProvider != null) {mybatisPlus.setDatabaseIdProvider(this.databaseIdProvider);}if (StringUtils.hasLength(this.properties.getTypeAliasesPackage())) {mybatisPlus.setTypeAliasesPackage(this.properties.getTypeAliasesPackage());}if (StringUtils.hasLength(this.properties.getTypeHandlersPackage())) {mybatisPlus.setTypeHandlersPackage(this.properties.getTypeHandlersPackage());}if (!ObjectUtils.isEmpty(this.properties.resolveMapperLocations())) {mybatisPlus.setMapperLocations(this.properties.resolveMapperLocations());}return mybatisPlus;}@Bean("globalConfiguration")public GlobalConfig globalConfig(@Qualifier("myMetaObjectHandler") ModelMetaObjectHandler myMetaObjectHandler,@Qualifier("customIdGenerator") CustomerIdGenerator customIdGenerator){GlobalConfig globalConfig = new GlobalConfig();globalConfig.setMetaObjectHandler(myMetaObjectHandler);globalConfig.setIdentifierGenerator(customIdGenerator);return globalConfig;}@Bean("myMetaObjectHandler")public ModelMetaObjectHandler modelMetaObjectHandler(){return new ModelMetaObjectHandler();}@Bean("customIdGenerator")public CustomerIdGenerator customerIdGenerator(){return new CustomerIdGenerator();}
}

4、使用说明

在Controller层、Service层和Dao层的方法或者类加上@DataSource(name="数据源名字")注解，完成数据源的自动切换，其中数据源名字来自DynamicDataSourceConfig中dynamicDataSource方法中定义的数据源

4.1、类级别注解

在类上添加多数据源注解，类中的所有方法都是使用注解中设置的数据源

4.1.1、Controller层用法

@RestController
@DataSource(name = "default")
@RequestMapping("/Order")
public class OrderController{// 所有方法默认使用default数据源@GetMapping("/list")public List<Order> queryAll() {// ...}// 默认使用default数据源@GetMapping("/{id}")public Order selectById(@PathVariable Long id) {// ...}
}

4.1.2、Service层用法

Service层使用多数据源注解时，需使用在@Service修饰的类上多数据源注解才能生效

@Service
@DataSource(name = "default")
public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements OrderService {// 所有方法默认使用default数据源public List<Order> findAll() {// ...}// 默认使用default数据源public Order findById() {// ...}
}

4.1.3、Dao层用法

Dao层使用多数据源注解时，需使用在@Component、@Repository或者@Mapper修饰的Dao层接口上多数据源注解才能生效

@Component
@DataSource(name = "default")
public interface OrderMapper extends BaseMapper<Order> {// 使用default数据源Order getById(@Param("id")Long id);// 使用default数据源List<Order> getList();}

4.2、方法级别注解

在方法上添加多数据源注解，具体方法使用注解中设置的数据源

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService{// 使用testDataSource数据源@DataSource(name = "testDataSource")public User getUserById(Long id) {// ...}// 使用default数据源@DataSource(name = "default") public User deleteUserById(Long id) {// ...}// 使用默认数据源(default数据源)public void updateUser(User user) {// ...}
}

Controller层与Dao层用法与类级别注解部分的使用介绍类似，此处不再赘述。

4.3、混合使用

多数据源注解的优先级别：方法级别注解>类级别注解>无注解（默认数据源）

当类和方法中都使用多数据源注解，会按照优先级别选择具体数据源

@Service
@DataSource(name = "testDataSource")
public class ProductServiceImpl extends ServiceImpl<ProductMapper, Product> implements ProductService{// 继承类注解，使用testDataSource数据源public Product getProduct(Long id) {// ...}// 方法级别注解的优先级最高，优先使用方法注解，使用default数据源@DataSource(name = "default")public void updateProduct(Product product) {// ...}
}

Controller层与Dao层用法与类级别注解部分的使用介绍类似，此处不再赘述。

5、注意事项

⚠️ 重要限制：由于数据源切换基于AOP，与@Transactional注解联用时需注意：

事务注解应加在数据源注解外层：

// ✅ 正确：事务在外层
@Transactional
@DataSource(name = "slave1")
public void transactionalMethod() { /* ... */ }// ❌ 危险：数据源切换可能不生效
@DataSource(name = "slave1")
@Transactional
public void riskyMethod() { /* ... */ }