使用AbstractRoutingDataSource实现数据源动态切换的实例

@Component
public class TenantInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        String tenantId = request.getHeader("X-TenantID");
        if (tenantId != null) {
            TenantContext.setCurrentTenant(tenantId);
        }
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        TenantContext.clear();
    }
}

public class TenantContext {
    private static final ThreadLocal<String> currentTenant = new ThreadLocal<>();

    public static void setCurrentTenant(String tenantId) {
        currentTenant.set(tenantId);
    }

    public static String getCurrentTenant() {
        return currentTenant.get();
    }

    public static void clear() {
        currentTenant.remove();
    }
}

public class MultiTenantDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return TenantContext.getCurrentTenant();
    }
}

@Configuration
public class DataSourceConfig {

    @Bean
    public DataSource dataSource() {
        MultiTenantDataSource dataSource = new MultiTenantDataSource();

        Map<Object, Object> targetDataSources = new HashMap<>();
        // 假设已经有一个方法来获取所有租户的数据源配置
        Map<String, DataSource> tenantDataSources = tenantDataSources();
        targetDataSources.putAll(tenantDataSources);

        dataSource.setTargetDataSources(targetDataSources);
        dataSource.setDefaultTargetDataSource(defaultDataSource()); // 默认数据源
        dataSource.afterPropertiesSet();
        return dataSource;
    }

    private Map<String, DataSource> tenantDataSources() {
        // 这里应该从配置文件或数据库中加载所有租户的数据源配置
        // 举例，假设有两个租户tenantA和tenantB
        Map<String, DataSource> result = new HashMap<>();
        result.put("tenantA", createDataSource("jdbc:mysql://localhost:3306/tenantA"));
        result.put("tenantB", createDataSource("jdbc:mysql://localhost:3306/tenantB"));
        return result;
    }

    private DataSource createDataSource(String url) {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUrl(url);
        dataSource.setUsername("username");
        dataSource.setPassword("password");
        return dataSource;
    }

    private DataSource defaultDataSource() {
        // 定义默认数据源
        return createDataSource("jdbc:mysql://localhost:3306/defaultDb");
    }
}

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    @Autowired
    private TenantInterceptor tenantInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(tenantInterceptor);
    }
}