Apache Commons Introduction (reprint)

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?

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

Apache Commons Introduction (reprint)