apache-commons项目介绍

Apache Commons项目简介之Attributes Apache Commons项目简介之Attributes 
0.简介

 

http://commons.apache.org

 

 
Apache Commons项目是专注于开发可重用的Java组件。 
Apache Commons项目由三部分组成： 
Commons Proper - 可重用Java组件库。 
Commons Sandbox - Java组件开发工作空间。 
Commons Dormant - sandbox中不活跃的项目存储库。
Apache Commons开发人员使每个组件尽可能少的依赖其他的lib，以便这些组件可以方便的部署，而不是需要将依赖的库依次部署。另外，Commons组件的接口尽可能的保持不变，这样可以在实现这些组件的时候针对接口进行开发，确保兼容性。 
本文主要介绍第一部分的项目，即可重用的稳定的Java组件库。由于库中的每个子项目都包含了特定的功能，所以本文不会对这些功能面面俱到的介绍，而是针对库中的每个子项目，尽可能的介绍其应用场景，以及列举典型的样例。 

Components
Attributes	Runtime API to metadata attributes such as doclet tags.
BeanUtils	Easy-to-use wrappers around the Java reflection and introspection APIs.
Betwixt	Services for mapping JavaBeans to XML documents, and vice versa.
Chain	Chain of Responsibility pattern implemention.
CLI	Command Line arguments parser.
Codec	General encoding/decoding algorithms (for example phonetic, base64, URL).
Collections	Extends or augments the Java Collections Framework.
Compress	Defines an API for working with tar, zip and bzip2 files.
Configuration	Reading of configuration/preferences files in various formats.
Daemon	Alternative invocation mechanism for unix-daemon-like java code.
DBCP	Database connection pooling services.
DbUtils	JDBC helper library.
Digester	XML-to-Java-object mapping utility.
Discovery	Tools for locating resources by mapping service/reference names to resource names.
EL	Interpreter for the Expression Language defined by the JSP 2.0 specification.
Email	Library for sending e-mail from Java.
Exec	API for dealing with external process execution and environment management in Java.
FileUpload	File upload capability for your servlets and web applications.
IO	Collection of I/O utilities.
JCI	Java Compiler Interface
Jelly	XML based scripting and processing engine.
Jexl	Expression language which extends the Expression Language of the JSTL.
JXPath	Utilities for manipulating Java Beans using the XPath syntax.
Lang	Provides extra functionality for classes in java.lang.
Launcher	Cross platform Java application launcher.
Logging	Wrapper around a variety of logging API implementations.
Math	Lightweight, self-contained mathematics and statistics components.
Modeler	Mechanisms to create Model MBeans compatible with JMX specification.
Net	Collection of network utilities and protocol implementations.
Pool	Generic object pooling component.
Primitives	Smaller, faster and easier to work with types supporting Java primitive types.
Proxy	Library for creating dynamic proxies.
Sanselan	A pure-Java image library.
SCXML	An implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine. It is capable of executing a state machine defined using a SCXML document, and abstracts out the environment interfaces.
Transaction	Implementations for multi level locks, transactional collections and transactional file access.
Validator	Framework to define validators and validation rules in an xml file.
VFS	Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system.