1.Spring实现模块化的缺陷
(1) 配置文件复杂难于维护
(2) Bean之间的依赖是静态的，在容器启动后运行期是无法更新的
(3) Bean之间的依赖是容器自动计算出来的，开发人员无法操作，对Circle依赖支持不好
2. Spring DM extender
The Spring DM extender is an OSGi bundle that scans bundles for Spring configuration files
and manages (creates,destroys, and updates) a Spring application context on their behalf.
Spring DM monitors the bundle lifecycle in order to determine when to trigger the
appropriate actions. Once Spring DM is deployed inside an OSGi container, it can
automatically detect Spring-powered components based on the presence of the
Spring application context configuration file as well as through certain dedicated
headers in the manifest file of the bundle. When a bundle with the appropriate
configuration is started, a Spring container is also configured and embedded inside
the component. By doing this, Spring DM implements the Extender pattern.
3. Benefits of SpringDM
Enforces module boundaries and adds dynamics at runtime;
Detects and manages Spring-powered and web-powered bundles；
Enables transparent(透明的) configuration, starting and stopping Spring containers
inside Spring-powered bundles；
Provides facilities related to service management and use；
Transparently handles the dynamic aspects of OSGi；
Interact with existing bundles using a variety of different technologies.
4. 网络资源
http://www.springsource.org/osgi
http://www.eclipse.org/gemini/