在復雜的企業應用中，多數據源管理是常見需求。本文將介紹如何基于Spring Boot實現優雅的動態數據源切換方案，通過自定義注解和AOP實現透明化切換。
核心設計思路
通過三層結構實現數據源動態路由：
1. 注解層：聲明式標記數據源
2. 路由層：基于ThreadLocal的上下文管理
3. 切面層：在方法執行前后自動切換數據源
核心實現代碼
1. 數據源注解定義
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {String name() default ""; // 數據源名稱
}2. 動態數據源上下文
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(); // 關鍵初始化}@Overrideprotected Object determineCurrentLookupKey() {return getDataSourceKey(); // 獲取當前數據源標識}// 數據源操作工具方法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切面實現
@Aspect
@Component
@Order(-1) // 確保在事務切面前執行
public class DataSourceAspect {@Around("@within(DataSource) || @annotation(DataSource)")public Object around(ProceedingJoinPoint point) throws Throwable {MethodSignature signature = (MethodSignature) point.getSignature();Method method = signature.getMethod();// 優先級：方法注解 > 類注解 > 默認數據源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(); // 執行目標方法} finally {DynamicDataSourceContext.clearDataSourceKey(); // 清理數據源標識}}
}自動配置
在`src/main/resources/META-INF/spring`目錄下創建文件：
org.springframework.boot.autoconfigure.AutoConfiguration.imports
com.test.datasourcestater.aspect.DataSourceAspect使用示例
1、新增動態切換數據源定義
@Configuration
@Component
public class DynamicDataSourceConfig {//默認數據源定義@Resource(name = "defaultDataSource")private DataSource defaultDataSource;//其他數據源定義@Resource(name = "testDataSource")private DataSource testDataSource;@Bean("dynamicDataSource")@Primarypublic DynamicDataSourceContext dynamicDataSource() {Map<Object, Object> targetDataSources = new HashMap<>();//添加默認數據源和其他數據源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;}
}其他數據源定義：
@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");// 數據庫連接地址basicDataSourceDecrypt.setJdbcUrl(url);// 最小空閑連接，默認值10，小于0或大于maximum-pool-size，都會重置為maximum-pool-sizebasicDataSourceDecrypt.setMinimumIdle(minIdle);// 最大連接數，小于等于0會被重置為默認值10；大于零小于1會被重置為minimum-idle的值basicDataSourceDecrypt.setMaximumPoolSize(maxActive);// 空閑連接超時時間，默認值600000（10分鐘），大于等于max-lifetime且max-lifetime>0，會被重置為0；不等于0且小于10秒，會被重置為10秒。basicDataSourceDecrypt.setIdleTimeout(30000);// 連接最大存活時間，不等于0且小于30秒，會被重置為默認值30分鐘.設置應該比mysql設置的超時時間短basicDataSourceDecrypt.setMaxLifetime(360000L);// 連接超時時間：毫秒，小于250毫秒，否則被重置為默認值30秒basicDataSourceDecrypt.setConnectionTimeout(500);// 用于測試連接是否可用的查詢語句basicDataSourceDecrypt.setConnectionTestQuery(validationQuery);return basicDataSourceDecrypt;}
}2、修改原始的DataSourceConfig為默認數據源
- 將datasource bean 定義名稱改成@Bean("defaultDataSource")
- 將@Qualifier("dataSource")改成@Qualifier("dynamicDataSource") 參考代碼，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");// 數據庫連接地址basicDataSourceDecrypt.setJdbcUrl(url);// 最小空閑連接，默認值10，小于0或大于maximum-pool-size，都會重置為maximum-pool-sizebasicDataSourceDecrypt.setMinimumIdle(minIdle);// 最大連接數，小于等于0會被重置為默認值10；大于零小于1會被重置為minimum-idle的值basicDataSourceDecrypt.setMaximumPoolSize(maxActive);// 空閑連接超時時間，默認值600000（10分鐘），大于等于max-lifetime且max-lifetime>0，會被重置為0；不等于0且小于10秒，會被重置為10秒。basicDataSourceDecrypt.setIdleTimeout(60000);// 連接最大存活時間，不等于0且小于30秒，會被重置為默認值30分鐘.設置應該比mysql設置的超時時間短basicDataSourceDecrypt.setMaxLifetime(600000);// 連接超時時間：毫秒，小于250毫秒，否則被重置為默認值30秒basicDataSourceDecrypt.setConnectionTimeout(30000);// 用于測試連接是否可用的查詢語句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分頁插件*/@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;}/*** 這里全部使用mybatis-autoconfigure 已經自動加載的資源。不手動指定* 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、使用說明
在Controller層、Service層和Dao層的方法或者類加上@DataSource(name="數據源名字")注解，完成數據源的自動切換，其中數據源名字來自DynamicDataSourceConfig中dynamicDataSource方法中定義的數據源
4.1、類級別注解
在類上添加多數據源注解，類中的所有方法都是使用注解中設置的數據源
4.1.1、Controller層用法
@RestController
@DataSource(name = "default")
@RequestMapping("/Order")
public class OrderController{// 所有方法默認使用default數據源@GetMapping("/list")public List<Order> queryAll() {// ...}// 默認使用default數據源@GetMapping("/{id}")public Order selectById(@PathVariable Long id) {// ...}
}4.1.2、Service層用法
Service層使用多數據源注解時，需使用在@Service修飾的類上多數據源注解才能生效
@Service
@DataSource(name = "default")
public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements OrderService {// 所有方法默認使用default數據源public List<Order> findAll() {// ...}// 默認使用default數據源public Order findById() {// ...}
}4.1.3、Dao層用法
Dao層使用多數據源注解時，需使用在@Component、@Repository或者@Mapper修飾的Dao層接口上多數據源注解才能生效
@Component
@DataSource(name = "default")
public interface OrderMapper extends BaseMapper<Order> {// 使用default數據源Order getById(@Param("id")Long id);// 使用default數據源List<Order> getList();}4.2、方法級別注解
在方法上添加多數據源注解，具體方法使用注解中設置的數據源
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService{// 使用testDataSource數據源@DataSource(name = "testDataSource")public User getUserById(Long id) {// ...}// 使用default數據源@DataSource(name = "default") public User deleteUserById(Long id) {// ...}// 使用默認數據源(default數據源)public void updateUser(User user) {// ...}
}Controller層與Dao層用法與類級別注解部分的使用介紹類似，此處不再贅述。
4.3、混合使用
多數據源注解的優先級別：方法級別注解>類級別注解>無注解（默認數據源）
當類和方法中都使用多數據源注解，會按照優先級別選擇具體數據源
@Service
@DataSource(name = "testDataSource")
public class ProductServiceImpl extends ServiceImpl<ProductMapper, Product> implements ProductService{// 繼承類注解，使用testDataSource數據源public Product getProduct(Long id) {// ...}// 方法級別注解的優先級最高，優先使用方法注解，使用default數據源@DataSource(name = "default")public void updateProduct(Product product) {// ...}
}Controller層與Dao層用法與類級別注解部分的使用介紹類似，此處不再贅述。
5、注意事項
???重要限制：由于數據源切換基于AOP，與@Transactional注解聯用時需注意：
- 事務注解應加在數據源注解外層：
// ? 正確：事務在外層
@Transactional
@DataSource(name = "slave1")
public void transactionalMethod() { /* ... */ }// ? 危險：數據源切換可能不生效
@DataSource(name = "slave1")
@Transactional
public void riskyMethod() { /* ... */ }總結
本文實現的多數據源方案具有以下優勢：
1. 非侵入式：通過注解透明切換，不影響業務邏輯
2. 靈活配置：支持方法級和類級數據源指定
3. 線程安全：基于ThreadLocal的上下文管理
4. 易于擴展：可快速添加新數據源
通過這種設計，開發者可以輕松管理多個數據源，特別適用于多租戶系統、讀寫分離、分庫分表等復雜場景。完整代碼已托管至Gitee，gitee地址：https://gitee.com/mutigmss/multiple-data-source-stater
歡迎在評論區交流使用體驗和優化建議！
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