Spring動(dòng)態(tài)注冊多數(shù)據(jù)源的實(shí)現(xiàn)方法

TenantConfigEntity（租戶信息）
@EqualsAndHashCode(callSuper = false)
@Data
@FieldDefaults(level = AccessLevel.PRIVATE)
public class TenantConfigEntity {
 /**
  * 租戶id
  **/
 Integer tenantId;
 /**
  * 租戶名稱
  **/
 String tenantName;
 /**
  * 租戶名稱key
  **/
 String tenantKey;
 /**
  * 數(shù)據(jù)庫url
  **/
 String dbUrl;
 /**
  * 數(shù)據(jù)庫用戶名
  **/
 String dbUser;
 /**
  * 數(shù)據(jù)庫密碼
  **/
 String dbPassword;
 /**
  * 數(shù)據(jù)庫public_key
  **/
 String dbPublicKey;
}
DataSourceUtil（輔助工具類，非必要）
public class DataSourceUtil {
 private static final String DATA_SOURCE_BEAN_KEY_SUFFIX = "_data_source";
 private static final String JDBC_URL_ARGS = "?useUnicode=true&characterEncoding=UTF-8&useOldAliasMetadataBehavior=true&zeroDateTimeBehavior=convertToNull";
 private static final String CONNECTION_PROPERTIES = "config.decrypt=true;config.decrypt.key=";
 /**
  * 拼接數(shù)據(jù)源的spring bean key
  */
 public static String getDataSourceBeanKey(String tenantKey) {
  if (!StringUtils.hasText(tenantKey)) {
   return null;
  }
  return tenantKey + DATA_SOURCE_BEAN_KEY_SUFFIX;
 }
 /**
  * 拼接完整的JDBC URL
  */
 public static String getJDBCUrl(String baseUrl) {
  if (!StringUtils.hasText(baseUrl)) {
   return null;
  }
  return baseUrl + JDBC_URL_ARGS;
 }
 /**
  * 拼接完整的Druid連接屬性
  */
 public static String getConnectionProperties(String publicKey) {
  if (!StringUtils.hasText(publicKey)) {
   return null;
  }
  return CONNECTION_PROPERTIES + publicKey;
 }
}

public class DataSourceContextHolder {
 private static final ThreadLocal<String> dataSourceKey = new InheritableThreadLocal<>();
 public static void setDataSourceKey(String tenantKey) {
  dataSourceKey.set(tenantKey);
 }
 public static String getDataSourceKey() {
  return dataSourceKey.get();
 }
 public static void clearDataSourceKey() {
  dataSourceKey.remove();
 }
}

public class DynamicDataSource extends AbstractRoutingDataSource {
 @Autowired
 private ApplicationContext applicationContext;
 @Lazy
 @Autowired
 private DynamicDataSourceSummoner summoner;
 @Lazy
 @Autowired
 private TenantConfigDAO tenantConfigDAO;
 @Override
 protected String determineCurrentLookupKey() {
  String tenantKey = DataSourceContextHolder.getDataSourceKey();
  return DataSourceUtil.getDataSourceBeanKey(tenantKey);
 }
 @Override
 protected DataSource determineTargetDataSource() {
  String tenantKey = DataSourceContextHolder.getDataSourceKey();
  String beanKey = DataSourceUtil.getDataSourceBeanKey(tenantKey);
  if (!StringUtils.hasText(tenantKey) || applicationContext.containsBean(beanKey)) {
   return super.determineTargetDataSource();
  }
  if (tenantConfigDAO.exist(tenantKey)) {
   summoner.registerDynamicDataSources();
  }
  return super.determineTargetDataSource();
 }
}

@Slf4j
@Component
public class DynamicDataSourceSummoner implements ApplicationListener<ContextRefreshedEvent> {
 // 跟spring-data-source.xml的默認(rèn)數(shù)據(jù)源id保持一致
 private static final String DEFAULT_DATA_SOURCE_BEAN_KEY = "defaultDataSource";
 @Autowired
 private ConfigurableApplicationContext applicationContext;
 @Autowired
 private DynamicDataSource dynamicDataSource;
 @Autowired
 private TenantConfigDAO tenantConfigDAO;
 private static boolean loaded = false;
 /**
  * Spring加載完成后執(zhí)行
  */
 @Override
 public void onApplicationEvent(ContextRefreshedEvent event) {
  // 防止重復(fù)執(zhí)行
  if (!loaded) {
   loaded = true;
   try {
    registerDynamicDataSources();
   } catch (Exception e) {
    log.error("數(shù)據(jù)源初始化失敗, Exception:", e);
   }
  }
 }
 /**
  * 從數(shù)據(jù)庫讀取租戶的DB配置,并動(dòng)態(tài)注入Spring容器
  */
 public void registerDynamicDataSources() {
  // 獲取所有租戶的DB配置
  List<TenantConfigEntity> tenantConfigEntities = tenantConfigDAO.listAll();
  if (CollectionUtils.isEmpty(tenantConfigEntities)) {
   throw new IllegalStateException("應(yīng)用程序初始化失敗,請(qǐng)先配置數(shù)據(jù)源");
  }
  // 把數(shù)據(jù)源bean注冊到容器中
  addDataSourceBeans(tenantConfigEntities);
 }
 /**
  * 根據(jù)DataSource創(chuàng)建bean并注冊到容器中
  */
 private void addDataSourceBeans(List<TenantConfigEntity> tenantConfigEntities) {
  Map<Object, Object> targetDataSources = Maps.newLinkedHashMap();
  DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
  for (TenantConfigEntity entity : tenantConfigEntities) {
   String beanKey = DataSourceUtil.getDataSourceBeanKey(entity.getTenantKey());
   // 如果該數(shù)據(jù)源已經(jīng)在spring里面注冊過,則不重新注冊
   if (applicationContext.containsBean(beanKey)) {
    DruidDataSource existsDataSource = applicationContext.getBean(beanKey, DruidDataSource.class);
    if (isSameDataSource(existsDataSource, entity)) {
     continue;
    }
   }
   // 組裝bean
   AbstractBeanDefinition beanDefinition = getBeanDefinition(entity, beanKey);
   // 注冊bean
   beanFactory.registerBeanDefinition(beanKey, beanDefinition);
   // 放入map中，注意一定是剛才創(chuàng)建bean對(duì)象
   targetDataSources.put(beanKey, applicationContext.getBean(beanKey));
  }
  // 將創(chuàng)建的map對(duì)象set到 targetDataSources；
  dynamicDataSource.setTargetDataSources(targetDataSources);
  // 必須執(zhí)行此操作，才會(huì)重新初始化AbstractRoutingDataSource 中的 resolvedDataSources，也只有這樣，動(dòng)態(tài)切換才會(huì)起效
  dynamicDataSource.afterPropertiesSet();
 }
 /**
  * 組裝數(shù)據(jù)源spring bean
  */
 private AbstractBeanDefinition getBeanDefinition(TenantConfigEntity entity, String beanKey) {
  BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(DruidDataSource.class);
  builder.getBeanDefinition().setAttribute("id", beanKey);
  // 其他配置繼承defaultDataSource
  builder.setParentName(DEFAULT_DATA_SOURCE_BEAN_KEY);
  builder.setInitMethodName("init");
  builder.setDestroyMethodName("close");
  builder.addPropertyValue("name", beanKey);
  builder.addPropertyValue("url", DataSourceUtil.getJDBCUrl(entity.getDbUrl()));
  builder.addPropertyValue("username", entity.getDbUser());
  builder.addPropertyValue("password", entity.getDbPassword());
  builder.addPropertyValue("connectionProperties", DataSourceUtil.getConnectionProperties(entity.getDbPublicKey()));
  return builder.getBeanDefinition();
 }
 /**
  * 判斷Spring容器里面的DataSource與數(shù)據(jù)庫的DataSource信息是否一致
  * 備注:這里沒有判斷public_key,因?yàn)榱硗馊齻€(gè)信息基本可以確定唯一了
  */
 private boolean isSameDataSource(DruidDataSource existsDataSource, TenantConfigEntity entity) {
  boolean sameUrl = Objects.equals(existsDataSource.getUrl(), DataSourceUtil.getJDBCUrl(entity.getDbUrl()));
  if (!sameUrl) {
   return false;
  }
  boolean sameUser = Objects.equals(existsDataSource.getUsername(), entity.getDbUser());
  if (!sameUser) {
   return false;
  }
  try {
   String decryptPassword = ConfigTools.decrypt(entity.getDbPublicKey(), entity.getDbPassword());
   return Objects.equals(existsDataSource.getPassword(), decryptPassword);
  } catch (Exception e) {
   log.error("數(shù)據(jù)源密碼校驗(yàn)失敗,Exception:{}", e);
   return false;
  }
 }
}

<!-- 引入jdbc配置文件 -->
 <context:property-placeholder location="classpath:data.properties" ignore-unresolvable="true"/>
 <!-- 公共(默認(rèn))數(shù)據(jù)源 -->
 <bean id="defaultDataSource" class="com.alibaba.druid.pool.DruidDataSource"
   init-method="init" destroy-method="close">
  <!-- 基本屬性 url、user、password -->
  <property name="url" value="${ds.jdbcUrl}" />
  <property name="username" value="${ds.user}" />
  <property name="password" value="${ds.password}" />
  <!-- 配置初始化大小、最小、最大 -->
  <property name="initialSize" value="5" />
  <property name="minIdle" value="2" />
  <property name="maxActive" value="10" />
  <!-- 配置獲取連接等待超時(shí)的時(shí)間，單位是毫秒 -->
  <property name="maxWait" value="1000" />
  <!-- 配置間隔多久才進(jìn)行一次檢測，檢測需要關(guān)閉的空閑連接，單位是毫秒 -->
  <property name="timeBetweenEvictionRunsMillis" value="5000" />
  <!-- 配置一個(gè)連接在池中最小生存的時(shí)間，單位是毫秒 -->
  <property name="minEvictableIdleTimeMillis" value="240000" />
  <property name="validationQuery" value="SELECT 1" />
  <!--單位：秒，檢測連接是否有效的超時(shí)時(shí)間-->
  <property name="validationQueryTimeout" value="60" />
  <!--建議配置為true，不影響性能，并且保證安全性。申請(qǐng)連接的時(shí)候檢測，如果空閑時(shí)間大于timeBetweenEvictionRunsMillis，執(zhí)行validationQuery檢測連接是否有效-->
  <property name="testWhileIdle" value="true" />
  <!--申請(qǐng)連接時(shí)執(zhí)行validationQuery檢測連接是否有效，做了這個(gè)配置會(huì)降低性能。-->
  <property name="testOnBorrow" value="true" />
  <!--歸還連接時(shí)執(zhí)行validationQuery檢測連接是否有效，做了這個(gè)配置會(huì)降低性能。-->
  <property name="testOnReturn" value="false" />
  <!--Config Filter-->
  <property name="filters" value="config" />
  <property name="connectionProperties" value="config.decrypt=true;config.decrypt.key=${ds.publickey}" />
 </bean>
 <!-- 事務(wù)管理器 -->
 <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
  <property name="dataSource" ref="multipleDataSource"/>
 </bean>
 <!--多數(shù)據(jù)源-->
 <bean id="multipleDataSource" class="a.b.c.DynamicDataSource">
  <property name="defaultTargetDataSource" ref="defaultDataSource"/>
  <property name="targetDataSources">
   <map>
    <entry key="defaultDataSource" value-ref="defaultDataSource"/>
   </map>
  </property>
 </bean>
 <!-- 注解事務(wù)管理器 -->
 <!--這里的order值必須大于DynamicDataSourceAspectAdvice的order值-->
 <tx:annotation-driven transaction-manager="txManager" order="2"/>
 <!-- 創(chuàng)建SqlSessionFactory，同時(shí)指定數(shù)據(jù)源 -->
 <bean id="mainSqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
  <property name="dataSource" ref="multipleDataSource"/>
 </bean>
 <!-- DAO接口所在包名，Spring會(huì)自動(dòng)查找其下的DAO -->
 <bean id="mainSqlMapper" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
  <property name="sqlSessionFactoryBeanName" value="mainSqlSessionFactory"/>
  <property name="basePackage" value="a.b.c.*.dao"/>
 </bean>
 <bean id="defaultSqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
  <property name="dataSource" ref="defaultDataSource"/>
 </bean>
 <bean id="defaultSqlMapper" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
  <property name="sqlSessionFactoryBeanName" value="defaultSqlSessionFactory"/>
  <property name="basePackage" value="a.b.c.base.dal.dao"/>
 </bean>
 <!-- 其他配置省略 -->

@Slf4j
@Aspect
@Component
@Order(1) // 請(qǐng)注意：這里order一定要小于tx:annotation-driven的order，即先執(zhí)行DynamicDataSourceAspectAdvice切面，再執(zhí)行事務(wù)切面，才能獲取到最終的數(shù)據(jù)源
@EnableAspectJAutoProxy(proxyTargetClass = true)
public class DynamicDataSourceAspectAdvice {
 @Around("execution(* a.b.c.*.controller.*.*(..))")
 public Object doAround(ProceedingJoinPoint jp) throws Throwable {
  ServletRequestAttributes sra = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
  HttpServletRequest request = sra.getRequest();
  HttpServletResponse response = sra.getResponse();
  String tenantKey = request.getHeader("tenant");
  // 前端必須傳入tenant header, 否則返回400
  if (!StringUtils.hasText(tenantKey)) {
   WebUtils.toHttp(response).sendError(HttpServletResponse.SC_BAD_REQUEST);
   return null;
  }
  log.info("當(dāng)前租戶key:{}", tenantKey);
  DataSourceContextHolder.setDataSourceKey(tenantKey);
  Object result = jp.proceed();
  DataSourceContextHolder.clearDataSourceKey();
  return result;
 }
}