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This article mainly introduces what are the jar packages in Struts. It is very detailed and has a certain reference value. Friends who are interested must finish it!

Commons-beanutils.jar

Commons-Beanutils is a sub-project of the jakarta commons project. The purpose of this project is to help developers get / set the properties of Java Bean dynamically and solve the trouble of writing getXXX and setXXX every time.

Commons-digester.jar

Digester is originally just a tool in Jakarta Struts for working with struts-config.xml configuration files. Obviously, converting XML files into corresponding Java objects is a general-purpose feature, and the tool is supposed to have a wider range of uses, so it soon has a place in the Jakarta Commons project to provide a reusable Java component library.

Internally, Struts uses Digester from the Jakarta Commons [ASF, Commons] project to parse the Struts configuration file. Digester uses struts-config DTD to validate the format of the document and to create Java objects that the document describes. If the XML file contains informally documented elements, or if elements are used in an informal documented manner, Digester will not process the file.

Commons-fileupload.jar

Commons-FileUpload FileUpload makes it easy to add powerful and high-performance file upload capabilities to your applications and Servlet struts to use in uploading files.

Struts's validation framework relies on the following two packages:

Commons-validator.jar

(verification method) and verification rules. Supports the internationalization of verification rules and error messages. Struts uses it to validate the form.

Jakarta-oro.jar

Commons-EL Commons-Jexl Search Jakarta ORO Jakarta ORO a set of text processing tools, can provide perl5.0 compatible regular expressions, AWK-like regular expressions, glob expressions. It also provides functions such as replacement, segmentation, file name worry and so on.

Struts.jar

Struts core package.

Jar package for the rest

Commons-collections.jar

Extends the standard Java Collection framework to provide additional Map, List, and Set implementations as well as several useful tool class libraries. More powerful than java.util.*.

Commons-logging.jar:

One of the Apache Commons packages that includes logging capabilities. The package itself contains a Simple Logger, but the functionality is weak. At run time, it will first look for log4j in CLASSPATH, if there is, use log4j, if not, find the java.util.logging with JDK1.4, and use Simple Logger if it can't be found. The emergence of commons-logging.jar is a historical legacy of regret, when Apache strongly lobbied Sun to add log4j to JDK1.4, but the JDK1.4 project team is close to releasing JDK1.4 products, so it rejected Apache's request to use its own java.util.logging, which is far worse than log4j and has mediocre performance.

Later, Apache developed commons-logging.jar to be compatible with two logger. So for log programs written in commons-logging.jar, the underlying Logger can be switched, and you can choose log4j,java.util.logging or its own Simple Logger. However, I still strongly recommend using log4j because the performance of log4j is so high that the time it takes for log to output information is almost equal to that of System.out, while the average processing time for a log is only 5us. You can find the log4j configuration file that Hibernate has prepared for you in Hibernate's src directory. You just need to go to the Apache website to download log4j. Commons-logging.jar is also a required jar package.

These are all the contents of the article "what are the jar packages in Struts?" Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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