经常看到有一些commons打头的包，这些包都是Apache提供的公共包或API，比如数据库连接池DBCP，日志的CommonLogging，或者和IO和上传有关的包。
这些包Apache提供了一个下载地址，大家可以从官网获得相关Jar包。
Apache Commons Proper
Commons Proper is dedicated to one principal goal: creating and maintaining reusable Java components. The Commons Proper is a place for collaboration and sharing, where developers from throughout the Apache community can work together on projects to be shared by the Apache projects and Apache users.
Commons developers will make an effort to ensure that their components have minimal dependencies on other libraries, so that these components can be deployed easily. In addition, Commons components will keep their interfaces as stable as possible, so that Apache users (including other Apache projects) can implement these components without having to worry about changes in the future.
This article gives an overview of (some of) the components which can be found here.
We welcome participation from all that are interested, at all skill levels. Coding, documentation and testing are all critical parts of the software development process. If you are interested in participating in any of these aspects, please join us!
感谢