Apache commons简介

Apache Commons是一个非常有用的工具包，解决各种实际的通用问题，下面是一个简述表，详细信息访问http://jakarta.apache.org/commons/index.html

Components
Attributes	Attributes provides a runtime API to metadata attributes such as doclet tags, inspired by the Nanning and XRAI projects as well as JSR 175 and C# attrbutes.
BeanUtils	Commons-BeanUtils provides easy-to-use wrappers around the Java reflection and introspection APIs.
Betwixt	Betwixt provides services for mapping JavaBeans to XML documents, and vice versa.
Chain	Chain provides a "Chain of Responsibility" pattern implemention for organizing complex processing flows.
CLI	CLI provides a simple API for working with Comamnd Line arguments, options, option groups, mandatory options and so forth.
Codec	Codec contains some general encoding/decoding algorithms. Includes some phonetic encoders, Hex, Base64, and a URL encoder.
Collections	Commons-Collections provides a suite of classes that extend or augment the Java Collections Framework.
Configuration	Commons-Configuration Tools to assist in the reading of configuration/preferences files in various formats.
Daemon	An alternative invocation mechanism for unix-daemon-like java code.
DBCP	Commons-DBCP provides database connection pooling services.
DbUtils	DbUtils is a JDBC helper library that factors out mundane resource cleanup code for common database tasks.
Digester	Commons-Digester is an XML-to-Java-object mapping utility commonly used for parsing XML configuration files.
Discovery	Commons-Discovery provides tools for locating resources (including classes) by mapping service/reference names to resource names using a variety of schemes.
EL	Commons-EL provides an interpreter for the Expression Language which is defined by the JavaServer Pages(TM) specification, version 2.0.
Email	Email provides a simple library for sending e-mail from Java.
FileUpload	FileUpload makes it easy to add robust, high-performance, file upload capability to your servlets and web applications.
HttpClient	Commons-HttpClient provides a framework for working with the client-side of the HTTP protocol.
IO	IO is a collection of I/O utilities.
Jelly	Jelly is an XML based scripting and processing engine. Jelly borrows many good ideas from both JSP custom tags, Velocity, Cocoon and the scripting engine inside XDoclet. Jelly can be used from the command line, inside Ant or inside a Servlet.
Jexl	Jexl is an expression language which entends the Expression Language of the JSTL by bringing in some of the lessons leaned by the Velocity community.
JXPath	Commons-JXPath provides utilities for manipulating Java classes that conform to the JavaBeans naming conventions using the XPath syntax. It also supports maps, DOM and other object models.
Lang	Commons-Lang provides a very common set of utility classes that provide extra functionality for classes in java.lang.
Latka	Commons-Latka is an HTTP functional testing suite for automated QA, acceptance and regression testing.
Launcher	The Launcher Component is designed to be a cross platform Java application launcher. Commons-launcher eliminates the need for a batch or shell script to launch a Java class. The original Java classes come from the Jakarta Tomcat 4.0 project.
Logging	Commons-Logging is a wrapper around a variety of logging API implementations.
Math	Math is a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language.
Modeler	Commons-Modeler provides mechanisms to create Model MBeans compatible with the Java Management Extensions (JMX) specification.
Net	Net is a a collection of network utilities, based on the NetComponents codebase, including FTP clients etc.
Pool	Commons-Pool provides a generic object pooling interface, a toolkit for creating modular object pools and several general purpose pool implementations.
Primitives	Commons-Primitives provides smaller, faster and easier to work with types supporting Java primitive types. Currently Primitives is primarily focused on collections of primitives.
Resources	Resources provides a lightweight framework for defining and looking up internationalized message strings keyed by a java.util.Locale and a message key.
Transaction	Commons Transaction provides implementations for multi level locks, transactional collections and transactional file access and some other utility classes commonly used in transacional Java programming.
Validator	The commons-validator package provides a simple, extendable framework to define validators (validation methods) and validation rules in an xml file. There is support for internationalization of validation rules and error messages.

BeanUtils
Commons-BeanUtils 提供对 Java 反射和自省API的包装

Betwixt
Betwixt提供将 JavaBean 映射至 XML 文档，以及相反映射的服务.

Chain
Chain 提供实现组织复杂的处理流程的“责任链模式”.

CLI
CLI 提供针对命令行参数，选项，选项组，强制选项等的简单API.

Codec
Codec 包含一些通用的编码解码算法。包括一些语音编码器， Hex, Base64, 以及URL encoder.

Collections
Commons-Collections 提供一个类包来扩展和增加标准的 Java Collection框架

Configuration
Commons-Configuration 工具对各种各式的配置和参考文件提供读取帮助.

Daemon
一种 unix-daemon-like java 代码的替代机制

DBCP
Commons-DBCP 提供数据库连接池服务

DbUtils
DbUtils 是一个 JDBC helper 类库，完成数据库任务的简单的资源清除代码.

Digester
Commons-Digester 是一个 XML-Java对象的映射工具，用于解析 XML配置文件.

Discovery
Commons-Discovery 提供工具来定位资源 (包括类) ，通过使用各种模式来映射服务/引用名称和资源名称。.

EL
Commons-EL 提供在JSP2.0规范中定义的EL表达式的解释器.

FileUpload
FileUpload 使得在你可以在应用和Servlet中容易的加入强大和高性能的文件上传能力

HttpClient
Commons-HttpClient 提供了可以工作于HTTP协议客户端的一个框架.

IO
IO 是一个 I/O 工具集

Jelly
Jelly是一个基于 XML 的脚本和处理引擎。 Jelly 借鉴了 JSP 定指标签，Velocity, Cocoon和Xdoclet中的脚本引擎的许多优点。Jelly 可以用在命令行， Ant 或者 Servlet之中。

Jexl
Jexl是一个表达式语言，通过借鉴来自于Velocity的经验扩展了JSTL定义的表达式语言。.

JXPath
Commons-JXPath 提供了使用Xpath语法操纵符合Java类命名规范的 JavaBeans的工具。也支持 maps, DOM 和其他对象模型。.

Lang
Commons-Lang 提供了许多许多通用的工具类集，提供了一些java.lang中类的扩展功能

Latka
Commons-Latka 是一个HTTP 功能测试包，用于自动化的QA,验收和衰减测试.

Launcher
Launcher 组件是一个交叉平台的Java 应用载入器。 Commons-launcher 消除了需要批处理或者Shell脚本来载入Java 类。.原始的 Java 类来自于Jakarta Tomcat 4.0 项目

Logging
Commons-Logging 是一个各种 logging API实现的包裹类.

Math
Math 是一个轻量的，自包含的数学和统计组件，解决了许多非常通用但没有及时出现在Java标准语言中的实践问题.

Modeler
Commons-Modeler 提供了建模兼容JMX规范的 Mbean的机制.

Net
Net 是一个网络工具集，基于 NetComponents 代码，包括 FTP 客户端等等。

Pool
Commons-Pool 提供了通用对象池接口，一个用于创建模块化对象池的工具包，以及通常的对象池实现.

Primitives
Commons-Primitives提供了一个更小，更快和更易使用的对Java基本类型的支持。当前主要是针对基本类型的 collection。.

Validator
The commons-validator提供了一个简单的，可扩展的框架来在一个XML文件中定义校验器 (校验方法)和校验规则。支持校验规则的和错误消息的国际化。 <style type="text/css"> .CodeSamp { PADDING-RIGHT: 0.5em; MARGIN-TOP: 1em; PADDING-LEFT: 0.5em; FONT-SIZE: 10p; MARGIN-BOTTOM: 1em; PADDING-BOTTOM: 0.5em; MARGIN-LEFT: 0pt; PADDING-TOP: 0.5em; FONT-FAMILY: "Courier New"; BACKGROUND-COLOR: #000000; 640px;border: 1px solid #888888;color: #FFFFFF;} </style>