commons-beanutils.jar
Commons-Beanutils is a sub-project of the jakartacommons project. The purpose of developing this project is to help developers dynamically obtain/set the properties of JavaBeans, while solving the trouble of having to write getXXX and setXXX every time.
commons-digester.jar
Digester was originally just a tool in JakartaStruts, used to process the struts-config.xml configuration file. Obviously, converting XML files into corresponding Java objects is a very general function, and this tool deserves to be of wider use, so it soon became available in the JakartaCommons project (for providing a reusable Java component library) a place.
Internally, Struts uses Digester from the Jakarta Commons [ASF, Commons] project to parse Struts configuration files. Digester uses struts-configDTD to verify the format of the document and create the Java object described by the document. If an XML file contains undocumented elements, or uses elements in an undocumented manner, Digester will not process the file.
commons-fileupload.jar
Commons-FileUploadFileUpload makes it easy to add powerful and high-performance file upload capabilities to your applications and Servlets for uploading files in struts.
The verification framework of struts relies on the following two packages:
commons-validator.jar
(Verification method) and verification rules. Supports internationalization of validation rules and error messages. Struts uses it to validate forms.
jakarta-oro.jar
Commons-EL Commons-Jexl Search Jakarta OROJakartaORO is a set of text processing tools that can provide perl5.0 compatible regular expressions, AWK-like regular expressions, and glob expressions. It also provides functions such as replacement, splitting, and file name filtering.
struts.jar
Struts core package.
Other jar packages
commons-collections.jar
Extends the standard JavaCollection framework to provide additional Map, List and Set implementations as well as multiple useful utility libraries. The function is more powerful than java.util.*.
commons-logging.jar:
One of the Apache Commons packages that contains logging functionality. The package itself contains a SimpleLogger, but its functionality is very weak. When running, it will first look for log4j in CLASSPATH. If it exists, use log4j. If not, it will look for java.util.logging that comes with JDK1.4. If it cannot find it, it will use SimpleLogger. The emergence of commons-logging.jar is a regret left over from history. Apache tried its best to lobby Sun to add log4j to JDK1.4. However, the JDK1.4 project team was approaching the time to release JDK1.4 products, so Apache rejected it. The requirement is to use your own java.util.logging. The function of this package is far inferior to log4j, and the performance is average.
Later, Apache developed commons-logging.jar to be compatible with two loggers. Therefore, for log programs written with commons-logging.jar, the underlying Logger can be switched. You can choose log4j, java.util.logging or its own SimpleLogger. However, I still strongly recommend using log4j, because log4j has high performance, the log output time is almost equal to System.out, and processing a log only takes 5us on average. You can find the log4j configuration file that Hibernate has prepared for you in the src directory of Hibernate. You only need to go to the Apache website to download log4j. commons-logging.jar is also a necessary jar package.
This article comes from the CSDN blog. Please indicate the source when reprinting: http://blog.csdn.net/iamboy_1/archive/2009/12/31/5111415.aspx
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