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操作步骤如下：
1. k8s环境下，consumer端开启mesh模式
2. consumer端需要调用多个provider
3. provider有应用级注册和接口级注册，并且需要的provider不再同一个namespace下
4. 原有项目存在dubbo2.6与3.1多版本间的相互调用，在开启消费端mesh（dubbo3.1）后，无法调用到2.6的服务提供者

**问题：**

1. 如何实现在一个consumer下，调用多个namespace下的provider，并且provider有应用级注册和接口级注册
2. dubbo3.1消费端在开启mesh后，如何调用版本是2.6的服务提供者
*
 *     &#64;Autowired
 *     private GenericService genericHelloService;
 * }
 * </pre>
 *
 * @see org.apache.dubbo.config.spring.reference.ReferenceBeanBuilder
 * @see org.apache.dubbo.config.spring.ReferenceBean
 * @since 2.7.7
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.METHOD, ElementType.ANNOTATION_TYPE})
public @interface DubboReference {
    /**
     * Interface class, default value is void.class
     */
    Class<?> interfaceClass() default void.class;
    /**
     * Interface class name, default value is empty string
     */
    String interfaceName() default "";
    /**
     * Service version, default value is empty string
     */
    String version() default "";
    /**
     * Service group, default value is empty string
     */
    String group() default "";