Apache Commons Java Package introduction

For more information, please refer to: http://commons.apache.org/

First, Commons beanutils
Description: A toolset for beans. Since beans tend to have a bunch of get and set components, Beanutils also carries out some packaging on this basis.

Second, Commons CLI
Description: This is a tool for handling commands. For example, the main method input string[] need to parse. You can pre-define the rules for parameters, and then you can invoke the CLI to parse them.

Third, Commons Codec
Description: This tool is used for encoding and decoding, including Base64,url,soundx and so on. The people who use this tool should be very clear about this, I will not introduce more.

Iv. Commons Collections
Description: You can think of this tool as an extension of java.util.

Five, Commons Configuration
Description: This tool is used to help with configuration files and supports a variety of storage methods

Liu, Commons DBCP
Description: Database Connection pool, Tomcat is the use of this, do not need me to say it, to use their own to the site to see the instructions.

Seven, Commons dbutils
Description: I used to write a database program, often the database operation to do a separate package. Dbutils is such a tool that it is not necessary to repeat the work after development. What is worth one is that this tool is not a popular or-mapping tool (like hibernate), but simplifies database operations, such as

71, Commons FileUpload
Description: JSP upload file function How to do it?

Viii. Commons HttpClient
Description: This tool makes it easy to access the website programmatically.

IX, Commons IO
Description: Can be seen as an extension of java.io, I think it is very convenient to use.

Ten, Commons Jxpath
Description: XPath you know, then Jxpath is an XPath based on a Java object, that is, querying a Java object with XPath. This thing is still very imaginative.

Xi. Commons Lang
Description: This toolkit can be seen as an extension to Java.lang. Tools such as StringUtils, Stringescapeutils, Randomstringutils, Tokenizer, wordutils are provided.

12, Commons Logging
Description: Do you know log4j,logback?

13. Commons Math
Description: Look at your name and you should know what this bag is for. Some of the features offered by this package are duplicated with Commons Lang, but the package is more focused on doing math tools and more powerful.

14. Commons Net
Description: This package is still very useful, encapsulating a lot of network protocols.
1. FTP
2. NNTP
3. SMTP
4. POP3
5. Telnet
6. TFTP
7. Finger
8. Whois
9. Rexec/rcmd/rlogin
Ten. Time (rdate) and daytime
One. Echo
Discard.
NTP/SNTP.

XV, Commons Validator
Description: A tool used to help with validation. such as verifying the email string, date string and so on is legitimate.

16. Commons Virtual File System
Description: Provides access to a variety of resources. Supported resource types include

1. CIFS
2. FTP
3. Local Files
4. HTTP and HTTPS
5. SFTP
6. Temporary Files
7. WebDAV
8. Zip, Jar and Tar (uncompressed, tgz or tbz2)
9. Gzip and BZIP2
Ten. Res
One. Ram
This package is powerful and greatly simplifies the program's access to resources.

17, Commons Transaction
Description: Provides persistent layer transaction support

16, Commons Proxy
Description: Dynamic agent, Interceptor type of thing

18. Commons Pool
Description: Creating a new object and initializing the operation may consume a lot of time.
In scenarios where these objects need to be created and used frequently, in order to provide system performance, it is common practice to create an object pool that caches a certain number of objects into the object pool.
When you need to use it, remove the object directly from the object pool and throw the object back into the object pool when you are finished using it.
Apache's Commons pool component is a good helper for our object pooling technology.

19, Commons Launcher
Description: Create a cross-platform executable program

20. Commons Bean Scripting Framework (BSF)
Description: is an open source project that supports invoking scripting language (script) within a Java application and supports direct access to Java objects and methods in scripting languages. With it, you can use JavaScript, Python, XSLT, Perl, Tcl, ... in Java application. Wait a whole bunch of scripting language
. In turn, it is possible to invoke any Javabean,java object that has already been registered in these scripting language. It provides a complete API to implement the engine that accesses the scripting language through Java.

21, Commons Chain
Description: You can use commons Chain when you need to define and perform some sequential operations.

22, Commons Compress
Description: Is a class library for compressing and extracting files. Can operate AR, cpio, Unix dump, tar, zip, gzip, XZ, Pack200 and bzip2 formatted files, powerful

23, Commons Discovery
Description: A component is used to find an implementation instance of a pluggable interface that provides a common way to instantiate these implementations, and can manage the life cycle of a singleton (factory).

24. Commons exec
Description: Apache Commons Exec is a Java project on Apache that provides some common methods for executing external processes, as shown in the following code:

String line = "acrord32.exe/p/h" + file.getabsolutepath ();
CommandLine CommandLine = Commandline.parse (line);
Defaultexecutor executor = new Defaultexecutor ();
Executor.setexitvalue (1);
Executewatchdog watchdog = new Executewatchdog (60000);
Executor.setwatchdog (watchdog);
int exitvalue = Executor.execute (commandLine);

25, Commons jelly
Description: Jelly is able to convert XML into executable code, so jelly is an XML-and Java-based scripting and processing engine. Jelly draws on many of the advantages of the scripting engine in JSP-set indicators, Velocity, Cocoon, and Xdoclet. Jelly can be used in command line, Ant or servlet

See the table below:

Component	Describe
BCEL	Bytecode Engineering Library--analyze, create and manipulate Java class files
Beanutils	Easy-to-use Java reflection and introspection API
BSF	Bean Scripting Framework-Includes scripting language interfaces, and JSR-223
Chain	The realization of the responsibility chain pattern
Cli	The command-line argument parser.
Codec	Commonly used encoding/decoding algorithms (e.g. voice, base64,url).
Collections	Extend or enhance the Java collection framework.
Compress	Some interfaces defined for processing files such as Tar,zip,zbip2
Configuration	Read configuration/Preference files in various formats.
Csv	A component that reads and writes a comma-separated value file.
Daemon	can help you achieve a common Java application into the system of a back-end service.
DBCP	Database thread Pool Service
Dbutils	JDBC Helper Library
Digester	XML-To-Java Object Mapping tool.
Discovery	A tool that locates resources by mapping service names and reference names to resource names.
EL	The EL expression parser defined by the JSP2.0 specification.
Email	Libraries that send mail through Java
Exec	APIs in Java that handle external process execution and environment management are used.
FileUpload	The ability to add file uploads in Servlets and Web application
Functor	The Apache Commons Functor Library includes a number of basic constructs that can be reused in complex usage scenarios involving closures and higher-order functions.
Imaging (previously called Sanselan)	A pure Java Image Library.
Io	I/O toolset.
Mc.	Java Compiler interface
Jcs	Java Cache System
Jelly	XML-based scripting and processing engine.
Jexl	Expression language, which extends the expression language of jstl.
Jxpath	A utility kit that uses XPath syntax to manipulate Java beans.
Lang	The classes in Java.lang provide additional functionality.
Launcher	Launch a cross-platform Java application.
Logging	Wrapper for the implementation of various log APIs.
Math	Lightweight, non-dependent mathematical and statistical components.
Modeler	Provides a mechanism for creating model Mbeans that is compliant with the JMX specification
Net	Implements a collection of network tools and protocols.
OGNL	OGNL is object-graph Navigation language abbreviation, it is a powerful expression language, through its simple and consistent expression syntax, can access the object's arbitrary properties, call the method of the object, traverse the whole object's structure diagram, realize the field type conversion and other functions. It uses the same expression to access the properties of the object.
Pool	Common Object Pool component.
Primitives	Commons-primitives provides a smaller, faster, and easier-to-use support for Java basic types.
Proxy	Create a dynamic Agent package.
Scxml	The implementation of the finite state machine XML specification is designed to create and maintain the Java Scxml engine. It is able to execute a state machine defined using the Scxml document, and an interface that abstracts out the environment.
Validator	A framework that defines validators and validation rules through XML files.
Vfs	VFS encapsulates access to a wide variety of file systems into a unified application interface, which greatly simplifies the complexity of the application's own code. The stability of Apache project is also obvious, currently VFS support some of the following file systems, of course, you can also expand on your own. such as Ftp,smb,zip or a single logical file system
Weaver	Provides an easy way to enhance (weave) the compiled bytecode.

Apache Commons Java Package introduction