我在维基百科和其他网站上读过关于OSGi的文章,但我并没有真正看到大局。它说它是一个基于组件的平台,并且您可以在运行时重新加载模块。同样,到处都给出的“实际示例”是Eclipse插件框架。

我的问题是:

OSGi清晰而简单的定义是什么? 它能解决什么常见问题?

所谓“常见问题”,我指的是我们每天都要面对的问题,比如“OSGi能做些什么来让我们的工作更高效/有趣/简单?”


当前回答

OSGi提供了以下好处:

■基于Java的可移植安全执行环境

■服务管理系统,可用于跨包注册和共享服务,并将服务提供者与服务消费者分离

■动态模块系统,可用于动态安装和卸载 Java模块,OSGi称之为包

轻量级和可扩展的解决方案

其他回答

它还被用于在移动端带来额外的中间件和应用程序的可移植性。移动端可用于WinMo, Symbian, Android等。一旦与设备功能集成,就会出现碎片化。

You can, analogically speaking, change the motor of your car without turning it off. You can customize complex systems for the customers. See the power of Eclipse. You can reuse entire components. Better than just objects. You use a stable platform to develop component based Applications. The benefits of this are huge. You can build Components with the black box concept. Other components don't need to know about hidden interfaces, them see just the published interfaces. You can use in the same system several equal components, but in different releases, without compromise the application. OSGi solves the Jar Hell problem. With OSGi you develop thinking to architect systems with CBD

对于使用Java的每个人来说,有很多好处(我现在只提醒了这些)。

I don't care too much about the hotplugability of OSGi modules (at least currently). It's more the enforced modularity. Not having millions of "public" classes available on the classpath at any time protects well from circular dependencies: You have to really think about your public interfaces - not just in terms of the java language construct "public", but in terms of your library/module: What (exactly) are the components, that you want to make available for others? What (exactly) are the interfaces (of other modules) you really need to implement your functionality?

这很好,热插拔是附带的,但我宁愿重新启动我通常的应用程序,而不是测试所有的热插拔组合…

我发现OSGi有以下好处:

每个插件都是一个版本化的工件,它有自己的类加载器。 每个插件都依赖于它所包含的特定jar和其他特定版本的插件。 由于版本控制和隔离的类加载器,同一工件的不同版本可以同时加载。如果应用程序的一个组件依赖于插件的一个版本,而另一个组件依赖于另一个版本,那么它们可以同时加载。

这样,您就可以将应用程序构建为一组按需加载的版本化插件构件。每个插件都是一个独立的组件。就像Maven帮助您构建构建,使其可重复,并由创建它的工件的一组特定版本定义一样,OSGi帮助您在运行时完成这一点。

至少,OSGi让您考虑到模块化、代码重用、版本控制以及项目的一般管道。