常用开发类库 - Apache Commons包详解

Apache Commons是Apache软件基金会的项目。Commons的目的是提供可重用的、开源的Java代码。

Apache Commons包简介

Apache Commons提供了很多工具类库，他们几乎不依赖其他第三方的类库，接口稳定，集成简单，可以大大提高编码效率和代码质量。

Apache Commons组件库

请参考Apache Common官方网站：https://commons.apache.org/open in new window

Component	Description	Latest Version
BCELopen in new window	Byte Code Engineering
Library - analyze, create, and manipulate Java class files
[![6.7.0](https://img.shields.io/maven-open in new window
central/v/org.apache.bcel/bcel)](https://search.maven.org/artifact/org.apache.bcel/bcel/6.7.0/jaropen in new window)
2022-12-06
BeanUtilsopen in new window	Easy-to-use
wrappers around the Java reflection and introspection APIs.
[![1.9.4](https://img.shields.io/maven-central/v/commons-beanutils/commons-open in new window
beanutils)](https://search.maven.org/artifact/commons-beanutils/commons-open in new window
beanutils/1.9.4/jar)	2019-08-13
BSFopen in new window	Bean Scripting
Framework - interface to scripting languages, including JSR-223	3.1
2010-06-24
Chainopen in new window	_Chain of
Responsibility_ pattern implemention.	1.2	2008-06-02
CLIopen in new window	Command Line arguments
parser.	[![1.5.0](https://img.shields.io/maven-central/v/commons-cli/commons-open in new window
cli)](https://search.maven.org/artifact/commons-cli/commons-cli/1.5.0/jaropen in new window)
2021-10-27
Codecopen in new window	General
encoding/decoding algorithms (for example phonetic, base64, URL).
[![1.15](https://img.shields.io/maven-central/v/commons-codec/commons-open in new window
codec)](https://search.maven.org/artifact/commons-codec/commons-open in new window
codec/1.15/jar)	2020-09-01
Collectionsopen in new window	Extends
or augments the Java Collections Framework.
[![4.4](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
collections4)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
collections4/4.4/jar)	2019-07-05
Compressopen in new window	Defines an
API for working with tar, zip and bzip2 files.
[![1.22](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
compress)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
compress/1.22/jar)	2022-11-01
Configurationopen in new window
Reading of configuration/preferences files in various formats.
[![2.8.0](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
configuration2)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
configuration2/2.8.0/jar)	2022-07-03
Cryptoopen in new window	A cryptographic
library optimized with AES-NI wrapping Openssl or JCE algorithm
implementations.	[![1.2.0](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
crypto)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
crypto/1.2.0/jar)	2023-01-23
CSVopen in new window	Component for reading
and writing comma separated value files.
[![1.10.0](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
csv)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
csv/1.10.0/jar)	2023-02-02
Daemonopen in new window	Alternative
invocation mechanism for unix-daemon-like java code.
[![1.3.3](https://img.shields.io/maven-central/v/commons-daemon/commons-open in new window
daemon)](https://search.maven.org/artifact/commons-daemon/commons-open in new window
daemon/1.3.3/jar)	2022-11-29
DBCPopen in new window	Database connection
pooling services.	[![2.9.0](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
dbcp2)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
dbcp2/2.9.0/jar)	2021-08-04
DbUtilsopen in new window	JDBC helper
library.	[![1.7](https://img.shields.io/maven-central/v/commons-open in new window
dbutils/commons-dbutils)](https://search.maven.org/artifact/commons-open in new window
dbutils/commons-dbutils/1.7/jar)	2017-07-20
Digesteropen in new window	XML-to-Java-
object mapping utility.	[![3.2](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
digester3)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
digester3/3.2/jar)	2011-12-13
Emailopen in new window	Library for sending
e-mail from Java.	[![1.5](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
email)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
email/1.5/jar)	2017-08-01
Execopen in new window	API for dealing with
external process execution and environment management in Java.
[![1.3](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
exec)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
exec/1.3/jar)	2014-11-06
FileUploadopen in new window	File
upload capability for your servlets and web applications.
[![1.5](https://img.shields.io/maven-central/v/commons-fileupload/commons-open in new window
fileupload)](https://search.maven.org/artifact/commons-fileupload/commons-open in new window
fileupload/1.5/jar)	2023-23-13
Functoropen in new window	A functor is a
function that can be manipulated as an object, or an object representing a
single, generic function.	1.0	2011-??-??
Geometryopen in new window	Space and
coordinates.	[![1.0](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-geometry-
parent)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
geometry-parent/1.0/pom)	2021-08-21
[Imaging (previously called
Sanselan)](https://commons.apache.org/proper/commons-imaging/open in new window)	A pure-Java
image library.	[![1.0-alpha3](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
imaging)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
imaging/1.0-alpha3/jar)	2022-05-19
IOopen in new window	Collection of I/O
utilities.	[![2.11.0](https://img.shields.io/maven-central/v/commons-open in new window
io/commons-io)](https://search.maven.org/artifact/commons-io/commons-open in new window
io/2.11.0/jar)	2021-07-13
JCIopen in new window	Java Compiler
Interface	[![1.1](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
jci)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
jci/1.1/jar)	2013-10-14
JCSopen in new window	Java Caching System
[![3.0](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
jcs)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
jcs/3.0/jar)	2020-08-16
Jellyopen in new window	XML based scripting
and processing engine.	[![1.0.1](https://img.shields.io/maven-open in new window
central/v/commons-jelly/commons-
jelly)](https://search.maven.org/artifact/commons-jelly/commons-open in new window
jelly/1.0.1/jar)	2017-09-25
Jexlopen in new window	Expression language
which extends the Expression Language of the JSTL.
[![3.2.1](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
jexl3)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
jexl3/3.2.1/jar)	2021-06-25
JXPathopen in new window	Utilities for
manipulating Java Beans using the XPath syntax.
[![1.3](https://img.shields.io/maven-central/v/commons-jxpath/commons-open in new window
jxpath)](https://search.maven.org/artifact/commons-jxpath/commons-open in new window
jxpath/1.3/jar)	2008-08-14
Langopen in new window	Provides extra
functionality for classes in java.lang.
[![3.12.0](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
lang3)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
lang3/3.12.0/jar)	2021-02-26
Loggingopen in new window	Wrapper around
a variety of logging API implementations.
[![1.2](https://img.shields.io/maven-central/v/commons-logging/commons-open in new window
logging)](https://search.maven.org/artifact/commons-logging/commons-open in new window
logging/1.2/jar)	2014-07-11
Mathopen in new window	Lightweight, self-
contained mathematics and statistics components.
[![4.0-beta1](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-math-
parent)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
math4/4.0-beta1/jar)	2022-12-20
Netopen in new window	Collection of network
utilities and protocol implementations.
[![3.9.0](https://img.shields.io/maven-central/v/commons-net/commons-open in new window
net)](https://search.maven.org/artifact/commons-net/commons-net/3.9.0/jaropen in new window)
2022-12-02
Numbersopen in new window	Number types
(complex, quaternion, fraction) and utilities (arrays, combinatorics).
[![1.1](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
numbers-
parent)](https://central.sonatype.dev/artifact/org.apache.commons/commons-open in new window
numbers-bom/1.1)	2022-11-01
OGNLopen in new window	An Object-Graph
Navigation Language	4.0	2013-??-??
Poolopen in new window	Generic object
pooling component.	[![2.11.1](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
pool2)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
pool2/2.11.1/jar)	2021-08-18
Proxyopen in new window	Library for
creating dynamic proxies.	[![1.0](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
proxy)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
proxy/1.0/jar)	2008-02-28
RDFopen in new window	Common implementation
of RDF 1.1 that could be implemented by systems on the JVM.
[![0.5.0](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
rdf-parent)](https://search.maven.org/artifact/org.apache.commons/commons-rdf-open in new window
parent/0.5.0/pom)	2017-12-23
RNGopen in new window	Implementations of
random numbers generators.	[![1.5](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-rng-
parent)](https://central.sonatype.dev/artifact/org.apache.commons/commons-rng-open in new window
bom/1.5)	2022-10-10
SCXMLopen in new window	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.
[![0.9](https://img.shields.io/maven-central/v/commons-scxml/commons-open in new window
scxml)](https://search.maven.org/artifact/commons-scxml/commons-open in new window
scxml/0.9/jar)	2008-12-01
Statisticsopen in new window
Statistics.	[![1.0](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-statistics-
parent)](https://central.sonatype.dev/artifact/org.apache.commons/commons-open in new window
statistics-distribution/1.0)	2022-12-05
Textopen in new window	Apache Commons Text
is a library focused on algorithms working on strings.
[![1.10.0](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
text)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
text/1.10.0/jar)	2022-09-28
Validatoropen in new window	Framework
to define validators and validation rules in an xml file.
[![1.7](https://img.shields.io/maven-central/v/commons-validator/commons-open in new window
validator)](https://search.maven.org/artifact/commons-validator/commons-open in new window
validator/1.7/jar)	2020-08-07
VFSopen in new window	Virtual File System
component for treating files, FTP, SMB, ZIP and such like as a single logical
file system.	[![2.9.0](https://img.shields.io/maven-open in new window
central/v/org.apache.commons/commons-
vfs2)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
vfs2/2.9.0/jar)	2021-07-21
Weaveropen in new window	Provides an easy
way to enhance (weave) compiled bytecode.
[![2.0](https://img.shields.io/maven-central/v/org.apache.commons/commons-open in new window
weaver-parent)](https://search.maven.org/artifact/org.apache.commons/commons-open in new window
weaver-parent/2.0/pom)	2018-09-07

Apache Commons常用组件

Commons BeanUtils

Jakarta Commons项目提供了相当丰富的API，我们之前了解到的Commons Lang只是众多API的比较核心的一小部分而已。Commons下面还有相当数量的子项目，用于解决各种各样不同方向的实际问题，BeanUtils就是其中的一个，用于处理JavaBeans。它利用Java的反射机制，从动态的生成对bean的getter和setter的调用代码，到模拟创建一个动态的bean，等等。这个包看似简单，却是很多开源项目的基石：如在著名的Struts和Spring Framework中，我们都能找到BeanUtils的影子。大家猜猜看，有哪位名人是BeanUtils的作者之一？没错，就是Struts的创始人Craig McClanahan。

Commons BeanUtils一共包括如下5个包：

    org.apache.commons.beanutils – 核心包，定义一组Utils类和需要用到的接口规范
    org.apache.commons.beanutils.converters – 转换String到需要类型的类，实现Converter接口
    org.apache.commons.beanutils.locale –beanutils的locale敏感版本
    org.apache.commons.beanutils.locale.converters– converters的locale敏感版本
    org.apache.commons.collections – beanutils使用到的Collection类

说明：针对Bean的一个工具集。由于Bean往往是有一堆get和set组成，所以BeanUtils也是在此基础上进行一些包装。

使用示例：功能有很多，网站上有详细介绍。一个比较常用的功能是Bean Copy，也就是copy bean的属性。如果做分层架构开发的话就会用到，比如从PO（Persistent Object）拷贝数据到VO（Value Object）。

传统方法如下：

   //得到TeacherForm
   
   TeacherForm teacherForm=(TeacherForm)form;
   
   //构造Teacher对象
   
   Teacher teacher=new Teacher();
   
   //赋值
   teacher.setName(teacherForm.getName());
   teacher.setAge(teacherForm.getAge());
   teacher.setGender(teacherForm.getGender());
   teacher.setMajor(teacherForm.getMajor());
   teacher.setDepartment(teacherForm.getDepartment());
   
   //持久化Teacher对象到数据库
   HibernateDAO= ;
   HibernateDAO.save(teacher);
   
   使用BeanUtils后，代码就大大改观了，如下所示：
   
   //得到TeacherForm
   TeacherForm teacherForm=(TeacherForm)form;
   //构造Teacher对象
   Teacher teacher=new Teacher();
   
   //赋值
   BeanUtils.copyProperties(teacher,teacherForm);
   
   //持久化Teacher对象到数据库
   HibernateDAO= ;
   HibernateDAO.save(teacher);

Commons CLI

说明：这是一个处理命令的工具。比如main方法输入的string[]需要解析。你可以预先定义好参数的规则，然后就可以调用CLI来解析。

使用示例：

    // create Options object
    Options options = new Options();
    // add t option, option is the command parameter, false indicates that
    // this parameter is not required.
    
    options.addOption("t", false, "display current time");
    options.addOption("c", true, "country code");
    
    CommandLineParser parser = new PosixParser();
    CommandLine cmd = parser.parse( options, args);
    
    if(cmd.hasOption("t")) {
        // print the date and time
    }else {
        // print the date
    }
    
    // get c option value
    String countryCode = cmd.getOptionValue("c");
    
    if(countryCode == null) {
        // print default date
    }else {
        // print date for country specified by countryCode
    }

Commons Codec

说明：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。

Commons Collections

说明：Commons Collections，又是一个重量级的东西，为Java标准的Collections API提供了相当好的补充。我不知道其他人，就我自己而言，让我用java.util.Collection及其子类，加上java.util.Collections类提供的操作方法，处理一些简单的数据结构问题还可以，稍微复杂一点的就觉得有点头痛，很多细节的地方需要我插入这样那样的小逻辑，或者感觉它太死板，不够灵活，再或者确实有点晦涩吧。再说了，如果我只是处理一般的数据结构问题，为什么不自己用数组或者自定义的链表来做，再加上Jakarta Commons的Lang提供的ArrayUtils、StringUtils等，已经基本够了，性能可以保证，那么还要这个Collections API干嘛。当然，说到这里有些偏激了，Collections当然有它存在的道理，能够把常用的数据结构归纳起来，以通用的方式去维护和访问，这应该说是一种进步，但是用起来似乎不够友好。这个时候我就会想，如果Java比现在做得更好用些，或者有一套第三方的API把我的这些需求抽象出来，实现了，该多好。Commons Collections就是这样一套API。可以把这个工具看成是java.util的扩展。

Commons Collections包结构共包含12个：

    org.apache.commons.collections – CommonsCollections自定义的一组公用的接口和工具类
    org.apache.commons.collections.bag – 实现Bag接口的一组类
    org.apache.commons.collections.bidimap – 实现BidiMap系列接口的一组类
    org.apache.commons.collections.buffer – 实现Buffer接口的一组类
    org.apache.commons.collections.collection –实现java.util.Collection接口的一组类
    org.apache.commons.collections.comparators– 实现java.util.Comparator接口的一组类
    org.apache.commons.collections.functors –Commons Collections自定义的一组功能类
    org.apache.commons.collections.iterators – 实现java.util.Iterator接口的一组类
    org.apache.commons.collections.keyvalue – 实现集合和键/值映射相关的一组类
    org.apache.commons.collections.list – 实现java.util.List接口的一组类
    org.apache.commons.collections.map – 实现Map系列接口的一组类
    org.apache.commons.collections.set – 实现Set系列接口的一组类

使用示例：举一个简单的例子

    OrderedMap map = new LinkedMap();
    map.put("FIVE", "5");
    map.put("SIX", "6");
    map.put("SEVEN", "7");
    map.firstKey(); // returns "FIVE"
    map.nextKey("FIVE"); // returns "SIX"
    map.nextKey("SIX"); // returns "SEVEN"

Commons Configuration

说明：Commons-Configuration 工具对各种各式的配置和参考文件提供读取帮助，这个工具是用来帮助处理配置文件的，支持很多种存储方式。

Properties files
XML documents
Property list files (.plist)
JNDI
JDBC Datasource
System properties
Applet parameters
Servlet parameters

使用示例：举一个Properties的简单例子

    usergui.properties, definining the GUI,
    colors.background = #FFFFFF
    colors.foreground = #000080
    window.width = 500
    window.height = 300
    
    
    
    PropertiesConfiguration config = new PropertiesConfiguration("usergui.properties");
    config.setProperty("colors.background", "#000000);
    config.save();
    
    config.save("usergui.backup.properties);//save a copy
    Integer integer = config.getInteger("window.width");

Commons DBCP

说明：Commons-DBCP 提供数据库连接池服务，Database Connection pool、Tomcat就是用的这个，不用我多说了吧，要用的自己去网站上看说明。

Commons DbUtils

说明：我以前在写数据库程序的时候，往往把数据库操作单独做一个包。DbUtils就是这样一个工具，以后开发不用再重复这样的工作了。值得一体的是，这个工具并不是现在流行的OR- Mapping工具（比如Hibernate），只是简化数据库操作，比如

    QueryRunner run = new QueryRunner(dataSource);
    
    // Execute the query and get the results back from the handler
    Object[] result = (Object[]) run.query("SELECT * FROM Person WHERE name=?", "John Doe");

Commons FileUpload

说明：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，比如jsp的上传文件功能。

使用示例：

    // Create a factory for disk-based file items
    FileItemFactory factory = new DiskFileItemFactory();
    // Create a new file upload handler
    ServletFileUpload upload = new ServletFileUpload(factory);
    
    // Parse the request
    List /* FileItem */ items = upload.parseRequest(request);
    // Process the uploaded items
    Iterator iter = items.iterator();
        while (iter.hasNext()) {
            FileItem item = (FileItem) iter.next();
        if (item.isFormField()) {
            processFormField(item);
        } else {
            processUploadedFile(item);
        }
    }

Commons HttpClient

说明：Commons-HttpClient 提供了可以工作于HTTP协议客户端的一个框架，这个工具可以方便通过编程的方式去访问网站。

使用示例：最简单的Get操作

    GetMethod get = new GetMethod("http://jakarta.apache.org");
    // execute method and handle any error responses.
    ...
    InputStream in = get.getResponseBodyAsStream();
    // Process the data from the input stream.
    get.releaseConnection();

Commons IO

说明：IO是一个I/O工具集，可以看成是java.io的扩展，我觉得用起来非常方便。

使用示例：

1．读取Stream

标准代码：

    InputStream in = new URL( "http://jakarta.apache.org" ).openStream();
    try {
        InputStreamReader inR = new InputStreamReader( in );
        BufferedReader buf = new BufferedReader( inR );
        String line;
        while ( ( line = buf.readLine() ) != null ) {
            System.out.println( line );
        }
    } finally {
        in.close();
    }

使用IOUtils

    InputStream in = new URL( "http://jakarta.apache.org" ).openStream();
    try {
        System.out.println( IOUtils.toString( in ) );
    } finally {
        IOUtils.closeQuietly(in);
    }

2．读取文件

    File file = new File("/commons/io/project.properties");
    List lines = FileUtils.readLines(file, "UTF-8");

3．察看剩余空间

    long freeSpace = FileSystemUtils.freeSpace("C:/");

Commons JXPath

说明：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。Xpath你知道吧，那么JXpath就是基于Java对象的Xpath，也就是用Xpath对Java对象进行查询。这个东西还是很有想像力的。

使用示例：

    Address address = (Address)JXPathContext.newContext(vendor).
    getValue("locations[address/zipCode='90210']/address");

上述代码等同于

    Address address = null;
    Collection locations = vendor.getLocations();
    Iterator it = locations.iterator();
    while (it.hasNext()){
        Location location = (Location)it.next();
        String zipCode = location.getAddress().getZipCode();
        if (zipCode.equals("90210")){
            address = location.getAddress();
            break;
        }
    }

Commons Lang

说明：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。这个工具包可以看成是对java.lang的扩展。提供了诸如StringUtils, StringEscapeUtils, RandomStringUtils, Tokenizer, WordUtils等工具类。

Commons Logging

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

Commons Math

说明：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。这个包提供的功能有些和Commons Lang重复了，但是这个包更专注于做数学工具，功能更强大。

Commons Net

说明：Net是一个网络工具集，基于NetComponents代码，包括FTP客户端等等，封装了很多网络协议。

FTP
NNTP
SMTP
POP3
Telnet
TFTP
Finger
Whois
rexec/rcmd/rlogin
Time (rdate) and Daytime
Echo
Discard
NTP/SNTP

使用示例：

    TelnetClient telnet = new TelnetClient();
    telnet.connect( "192.168.1.99", 23 );
    InputStream in = telnet.getInputStream();
    PrintStream out = new PrintStream( telnet.getOutputStream() );
    ...
    telnet.close();

Commons 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。

Commons Validator

说明：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。用来帮助进行验证的工具。比如验证Email字符串，日期字符串等是否合法。

使用示例：

    // Get the Date validator
    DateValidator validator = DateValidator.getInstance();
    // Validate/Convert the date
    Date fooDate = validator.validate(fooString, "dd/MM/yyyy");
    if (fooDate == null) {
        // error...not a valid date
        return;
    }

Commons Virtual File System

说明：vfs提供对各种资源的访问接口。支持的资源类型包括

CIFS
FTP
Local Files
HTTP and HTTPS
SFTP
Temporary Files
WebDAV
Zip, Jar and Tar (uncompressed, tgz or tbz2)
gzip and bzip2
res
ram

这个包的功能很强大，极大的简化了程序对资源的访问。

使用示例：

从jar中读取文件

    // Locate the Jar file
    FileSystemManager fsManager = VFS.getManager();
            FileObject jarFile = fsManager.resolveFile( "jar:lib/aJarFile.jar" );
    
    // List the children of the Jar file
            FileObject[] children = jarFile.getChildren();
            System.out.println( "Children of " + jarFile.getName().getURI() );
            for ( int i = 0; i < children.length; i++ ){
            System.out.println( children[ i ].getName().getBaseName() );
            }

从smb读取文件

    StaticUserAuthenticator auth = new StaticUserAuthenticator("username", "password", null);
            FileSystemOptions opts = new FileSystemOptions();
            DefaultFileSystemConfigBuilder.getInstance().setUserAuthenticator(opts, auth);
            FileObject fo = VFS.getManager().resolveFile("smb://host/anyshare/dir", opts);

常用开发类库 - Apache Commons包详解

# Apache Commons包简介

# Apache Commons组件库

# Apache Commons常用组件

# Commons BeanUtils

# Commons CLI

# Commons Codec

# Commons Collections

# Commons Configuration

# Commons DBCP

# Commons DbUtils

# Commons FileUpload

# Commons HttpClient

# Commons IO

# Commons JXPath

# Commons Lang

# Commons Logging

# Commons Math

# Commons Net

# Commons Primitives

# Commons Validator

# Commons Virtual File System

# 引用资料

Apache Commons包简介

Apache Commons组件库

Apache Commons常用组件

Commons BeanUtils

Commons CLI

Commons Codec

Commons Collections

Commons Configuration

Commons DBCP

Commons DbUtils

Commons FileUpload

Commons HttpClient

Commons IO

Commons JXPath

Commons Lang

Commons Logging

Commons Math

Commons Net

Commons Primitives

Commons Validator

Commons Virtual File System

引用资料