JARs and open source projects commonly used in J2EE

•activation~ The jar package related to javaMail should be added to the lib together with mail.jar (mail.jar and activation.jar) when using javaMail, which is responsible for the data source and type of mail.
•Apache ActiveMQ ~ Apache produced, the most popular, powerful open source message bus. ActiveMQ is a JMS Provider implementation that fully supports the JMS1.1 and J2EE 1.4 specifications.
•ajaxtags~ajax provides tag library, which enables users to use ajax like ordinary jsp tags.
• Apache Ant ~ build tool for a number of other tasks such as documentation generation and test execution.
• Antlr~ syntax analyzer, for example, to help hibernate execute Hql statements.
•AOP Alliance~AOP Alliance AOP Alliance (http://aopalliance.sourceforge.net/) is a joint open source collaboration organization that collaborates among multiple projects to provide a set of standard AOP Java interfaces. Spring AOP is implemented based on the AOP Alliance standard API. If you plan to use Spring's AOP or any AOP-based feature, just use this JAR file.
•Asm~Hibernate uses this code generation library to enhance classes at runtime (used in conjunction with the java reflection mechanism). ASM bytecode library, a package that the cglib.jar package depends on. Required jar package.
• Aspectj~Aspect is another name for a cross-cutting concern. Aspects provide a mechanism by which cross-cutting concerns can be specified in a modular fashion.

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• Btm~Bitronix Transaction Manager~Multiple data source transaction management.
• Bsf~Bean Scripting Framework (BSF) is an open source project that supports calling scripting language (Script) in Java applications and supports scripting language to directly access Java objects and methods.

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•C3P0~ an open source JDBC connection pool, which implements data source and JNDI binding, supports JDBC3 specification and JDBC2 standard extension. Currently, open source projects using it include Hibernate, Spring, etc.
•Cglib~ The full name is Code Generation Library, which can be used to dynamically inherit Java classes or implement interfaces. It is used in many well-known open source projects. Hibernate uses it to achieve dynamic generation of PO bytecode, a very core library, and a necessary jar package.
•Commons(Apache Commons)~
common-annotations.jar: Both Spring and hibernate can be used, the dependency package of spring or hibernate annotation.

commons-bcel.jar: The Byte Code Engineering Library is used to analyze, create and process Java class files.

commons-beanutils.jar: This package contains some Bean utility classes and is a jar package that must be used.

commons-betwixt.jar: Provides services for mapping JavaBeans to XML documents, and vice versa.

commons-bsf.jar: Bean Scripting Framework. Interfaces to scripting languages, including JSR-223. BSF is a set of java classes, which can be downloaded. Currently it is bsf-bin- 2.3.1 version, with this baby, you can use JavaScript, Python, XSLT, Perl, tcl, ... etc. in java application Heap scripting language. The reverse is also possible, that is to call any registered JavaBean, java object in these scripting languages.

Commons-Chain.jar: is a Java class library that implements the Chain of Responsibility design pattern. As program developers, we often need to apply an object-oriented approach to a system that is actually procedural. Business analysts and managers typically describe such systems not using class hierarchies and sequence diagrams, but instead using flowcharts and workflow diagrams. But in any case, using an object-oriented approach to these problems brings more flexibility. Object-oriented design patterns, such as Template Method [GoF] and Chain of Responsibility [GoF], provide useful structures and behaviors to describe this sequential processing. Chain, a sub-project of Jakarta Commons, combines the above two patterns into a reusable Java framework for describing sequential processing flows. This framework, developed in the Jakarta Commons project community, has been widely accepted and used in many interesting applications, in particular it is used by the Struts and Shale application frameworks as the underlying mechanism for handling HTTP requests. You can use CommonsChain when you need to define and execute a set of sequential steps.

commons-cli-1.0.jar: This is a tool for processing commands. For example, the string[] input by the main method needs to be parsed. You can pre-define the rules for parameters, and then call the CLI to parse them.

commons-codec: Mainly includes core algorithms. Such as MD5. SHA1. Or conventional encryption and decryption algorithm: BASE64.

commons-collections.jar: Encapsulates various collection objects. Contains some collection classes developed by Apache, which are more powerful than java.util.*.

Commons-Compress.jar: Used to compress or decompress files into tar, zip, bzip2 and other formats.

Commons-Configuratio: is a configuration management class library for java applications. The configuration information of the software can be loaded from the properties or xml file to build the basic environment that supports the running of the software. In some cases with more and more complicated configuration files, using this configuration tool can simplify the analysis and management of configuration files. It also improves development efficiency and software maintainability.

Commons-csv: CSV (comma separated value) is the English abbreviation of (comma separated value), usually a plain text file. Commons-csv is used to read and write CSV files.

Commons-Daemon: A background service that can help you implement a common Java application programming system. For example, Tomcat uses this project to start and stop as a Linux and Windows service.

commons-dbutils: commons-dbutils is an open source JDBC tool class library provided by the Apache organization. It re-encapsulates the classes of traditional database operations, and can convert the result set into a List.

commons dbcp.jar: One of the mainstream database connection pools (DBCP, c3p0, proxool). To use DBCP alone, you need to use three packages: commons-dbpc.jar, commons-collections.jar, and commons-pool.jar.

commons-digester.jar: It can easily convert elements defined by XML documents into JAVA objects. In fact, its usage is a bit like a stack (of course, the internal principle is that old thing, but it provides a higher level of encapsulation) .

commons-discovery-0.2.jar: An implementation of the discovery mode, providing a common method for locating and instantiating classes or other resources. Use the best algorithm to get all implementations of the interface. This is especially useful when the user wants to find all the providers that offer a certain service.

commons-el: (Expression Language) is a Java class library used to parse the expression language of JSP 2.0 in the Apache organization.

Commons-Email:Library for sending e-mail from Java.

Commons-Exec: is a Java project on Apache that provides some common methods for executing external processes.

commons-fileupload.jar implements the file upload function package.

Commons-Functo: The library includes a large number of basic constructs that can be reused in complex usage scenarios involving closures and higher-order functions.

commons-httpclient.jar: The Commons-HttpClient project is specially designed and used to simplify various communication programming between HTTP client and server - it can realize various functions of conventional HTTP client programs (that is, browser programs) .

commons-io.jar implements reading and writing of character streams. It can be seen as an extension of java.io.

commons –JCI: Java Compiler Interface is a class library that encapsulates the Java compiler.

commons – JCS: Java Caching System. JAVA cache.

Commons-Jelly: Jelly is an XML-based code generation tool that converts XML documents into executable code.

Commons-Jexl: Jexl is an expression language that extends the expression language defined by JSTL by borrowing lessons from Velocity.

commons.jxpat: defines a simple XPath expression language parser

commons-lang.jar provides extensions for java.lang, programming basic classes.

Commons launcher: The Launcher component is a platform-independent Java application loader. Commons-launcher eliminates the need for batch or shell scripts to load Java classes. If you need to run a class with a main method on linux/windows, and the class references many jar and class files, you can use Launcher.

commons-logging.jar Common logging package.

Commons-Math: is a lightweight self-container package of mathematical and statistical computing methods on Apache, including most commonly used numerical algorithms.

Commons-Modeler: Java program provides a tool for creating MBeans models based on the JMX specification.

commons-net.jar provides FTP and other functions. This package implements many basic Internet-based protocols. The following are the protocols supported by commons: FTP/FTPS, NNTP, SMTP, POP3, Telnet, TFTP, Finger, Whoisrexec/rcmd/rlogin, Time (rdate) and Daytime Echo Discard NTP/SNTP.

commons-OGNL: Abbreviation for Object Graph Navigation Language. Compared with JSP and JSF, OGNL is a very powerful expression language (EL) for Java, which can be used to read and update the properties of Java objects.

Commons-Primitives provides a smaller, faster and easier-to-use support for Java primitives. Currently mainly for collection of basic types. .

commons-pool.jar: DBCP database connection pool, developed by Apache's Jakarta organization, Tomcat4's connection pool is also DBCP.

COmmons-Proxy: is a sub-project of Apache that encapsulates some common methods of Java object proxy.

Commons-Sanselan: is a pure java implementation library for reading and generating images, and also includes analyzing image information such as size, color space, and metadata.

commons-validator.jar: Tools used to help with validation. For example, verify whether the Email string, date string, etc. are legal.

Commons-Transaction aims to provide a lightweight, standardized, and efficient Java transaction multi-threaded programming toolkit, implementing multi-level locks, transaction collections, and transaction-level file access.

Commons-SCXML: It is the Java implementation version of SCXML engine, which basically covers the entire content of SCXML W3C specification.

Commons-vfs: VFS (Virtual File System virtual machine) provides a single application programming interface (API) for accessing various file systems, which greatly simplifies the complexity of the application code itself. Currently VFS supports FTP, Local Files, HTTP/HTTPS, SFTP, Temporary Files, Zip, Jar/Tar (uncompressed, tgz or tbz2), gzip/bzip2, res, ram, and all files in these file systems are encapsulated into FileObject. Class, the read and write operations of files are completed through this class. The path to the file is in the form of a URL. If you need to get some information about files in different formats in your normal work, such as file size, path, the last change time of the file, etc., or we need to perform some routine operations on the file, such as deleting files, copying files, etc., Then VFS (Virtual File System) in Apache Commons is an open source system you can consider.

CXF(Apache CXF)~Apache CXF is an open source Services framework, CXF helps you to use Frontend programming API to build and develop Services, like JAX-WS. These Services can support multiple protocols, such as: SOAP, XML/HTTP, RESTful HTTP or CORBA, and can run on multiple transport protocols, such as: HTTP, JMS or JBI, CXF greatly simplifies the creation of Services, and it inherits With the XFire tradition, it can be seamlessly integrated with Spring.


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•dom4j~ A Java XML API, similar to jdom, used to read and write XML files.
•Dozer~Dozer is a class library for copying JavaBean properties, similar to BeanUtils.
• Drools~jBPM5 merges the jBPM project and Drools Flow. Drools Flow has been around for several years and its purpose is to enable and prototype flexible and adaptable business processes by integrating business rules and complex event processing. These features have been proven not only to be feasible, but also to be of great value in the long run, being able to better manage the complexity of real-world use cases. Over the past few years, this content has been well integrated with the experience accumulated during the construction of jBPM, and jBPM5 is based on this foundation. But jBPM's vision hasn't changed, it's just been expanded. Drools Flow will no longer be developed independently, the latest version of Drools is already using jBPM5 to handle its flow requirements.
• DWR (Direct Web Remoting) is a remote server-side Ajax open source framework for improving the interaction between web pages and Java classes, which can help developers develop websites that contain AJAX technology. It allows code in the browser to use JAVA functions running on the web server as if it were in the browser.
•DisplayTag is a very useful table display tag, suitable for MVC pattern.

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•ehcache~Java cache framework EhCache EhCache is a pure Java in-process cache framework with fast, lean and other characteristics, and is the default CacheProvider in Hibernate.

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• FreeMarker is a template engine, a general tool for generating text output based on templates, written in pure Java.

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•Geronimo~Apache Geronimo is the open source J2EE server of the Apache Software Foundation, which integrates many advanced technologies and design concepts. Most of these techniques and philosophies originate from independent projects, and the configuration and deployment models vary. Geronimo fully integrates the configuration and deployment of these projects and methods into a unified, easy-to-use model.

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• h2~ an open source relational database.

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•Hamcrest~ is a relatively good JUnit test jar package.
• Hibernate
hibernate-annotations.jar Hibernate annotation dependency package.

hibernate-entitymanager.jar Hibernate's core library.

hibernate-jpa-2.0-api-1.0.1.Final.jar Hibernate dependency package used to define java persistence.

hibernate3.jar Hibernate core implementation.


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•Itext~ A java class library for generating PDF documents. Through iText, you can not only generate PDF or rtf documents, but also convert XML and Html files into PDF files.

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•Jackson~ is a class library used by Java to process data in JSON format, and its performance is very good.
•Jasypt~ a simple and easy-to-use String encryption tool.
• The location of lib package is adjusted after Jasper~Tomcat6.0 version, jasper-runtime.jar, jasper-compiler-jdt.jar, jasper-compiler.jar, etc. are all integrated into jasper.jar package. Compile class, if you want to manually compile JSP, it also includes other JAR packages under tomcat lib: jasper.jar;servlet-api.jar;el-api.jar;catalina.jar;catalina-ant.jar;jasper-el.jar; jasper-jdt.jar;tomcat-juli.jar;jsp-api.jar;.
• JFreeChart~ is an open chart drawing class library on the JAVA platform. It is written entirely in JAVA and is designed for applications, applets, servlets and JSP. JFreeChart can generate pie charts, bar charts, scatter plots, time series, Gantt charts, etc., and can generate PNG and The output in JPEG format can also be associated with PDF and EXCEL.
•Jaxen~Jaxen is an open source XPath library written in Java. This is adaptable to many different object models, including DOM, XOM, dom4j and JDOM. Also acts as an adapter, converting Java bytecode or XML Java beans to xml, allowing you to query these trees using XPath.
• Jbpm~ stands for Java Business Process Management (business process management). Open source project of JBOSS.
• Jettison ~ a set of StAX parsers and writers for reading and writing JSON. This makes it possible to implement JSON-based web services in service frameworks like CXF and XFire.
• Javassist is an open source library for analyzing, editing and creating Java bytecode. The structure of the class can be changed dynamically, or the class can be dynamically generated.
•JAXB (Java Architecture for XML Binding) is an industry standard, a technology that can generate Java classes according to XML Schema. In this process, JAXB also provides a method to reverse the XML instance document to generate the Java object tree, and can rewrite the content of the Java object tree to the XML instance document. On the other hand, JAXB provides a quick and easy way to bind XML schemas to Java representations, allowing Java developers to easily combine XML data and processing functions in Java applications.
• jcl-over-slf4j ~ components that are likely to be used in your project, using both JCL and SLF4J components respectively. For example, if Hibernate 3.5 and Struts are used in the project, or some other open source components of Apache, you probably don't want to use SLF4J's component log information to output to A, and use JCL's component log to output to B, then you yourself Where should the log information in the written code be written? To output log information uniformly through SLF4J, you need to use JCL-Over-SLF4J+SLF4J.
•Jmemcached~ is a Java version of the memcached cache server, basically compatible with memcached. jmemcached uses Apache MINA as a non-blocking network IO operation, but since version 0.7 jmemcached has switched to Netty as a network IO operation package.
•jsoup is a Java HTML parser, which can directly parse a URL address and HTML text content. It provides a very low-effort API for fetching and manipulating data through DOM, CSS, and jQuery-like manipulation methods.
•Joda-Time~ provides a set of Java class packages for handling date and time including ISO8601 standards. It can be used to completely replace the JDK Date and Calendar classes and still provide good integration
. Jolokia~ is a new way to access remote JMX MBeans, unlike the JSR-160 connector, it uses HTTP-based The JSON format is used as a communication protocol, providing JMX batch operations, etc.
•jpa-api~Java Persistence API. Not much to say~
•Jstl~implementation package using jstl tag.
•JS~ is used to execute javascript in JAVA?
•Jsr~JSR is the abbreviation of Java Specification Requests, which means Java Specification Request. It is a formal request to the JCP (Java Community Process) to add a standardized technical specification. Anyone can submit a JSR to add new APIs and services to the Java platform. JSR has become an important standard in the Java world.
• JTA~ is the Java Transaction API, translated into Java Transaction API.

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• Kahadb~ is the default message storage engine for activemq since version 5.4.

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•log4j~log.
•Logback~logback was developed by log4j author Ceki and gradually replaces log4j.
• Lucene is a sub-project of the 4 jakarta project group of the Apache Software Foundation. It is an open-source full-text search engine toolkit, that is, it is not a complete full-text search engine, but the architecture of a full-text search engine that provides a complete The query engine and indexing engine, part of the text analysis engine (English and German two western languages).
• The predecessor of MyBatis is iBatis. Is a data persistence layer framework.
• Mina (apache mina)~Apache MINA (Multipurpose Infrastructure for Network Applications) is a newer project of Apache organization, which provides a very convenient framework for developing high-performance and high-availability network applications. The currently released version of MINA supports the development of TCP/UDP applications based on Java NIO technology, serial communication programs (only available in the latest preview version), and the functions supported by MINA are further expanded.
•MVEL~MVEL is a powerful expression language for Java-based applications.
• neethi~Apache Neethi This component provides a non-complete WS-Policy implementation for Axis2, allowing Axis2 users to manipulate and compose policy documents. Is Axis2's tool for creating runtime representations of policy documents, and performing normalization, merging, and intersection operations on policy documents. WS-Policy provides a way to specify possible configurations of web services and enforce defined security and authentication.
•ORO~Jakarta ORO 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 filename filtering.
•poi~Apache POI is an open source library of the Apache Software Foundation. POI provides APIs for Java programs to read and write Microsoft Office format files.
•Quartz is another open source project of the OpenSymphony open source organization in the field of Job scheduling. It can be combined with J2EE and J2SE applications or used alone.
•Qrcode~QR Code is a matrix two-dimensional code symbol developed by Denso Corporation of Japan in September 1994. It has the information capacity of one-dimensional barcode and other two-dimensional barcodes, high reliability, and can represent Chinese characters. And the advantages of a variety of text information of images, strong confidentiality and anti-counterfeiting. This jar package is parsed to generate a QR code~
•Spring

spring-aop: Spring's aspect-oriented programming, providing AOP (aspect-oriented programming interface of the above-mentioned AOP alliance) implementation.

spring-asm: Spring's independent asm program requires an additional asm.jar package compared to version 2.5.

spring-aspects: spring provides integration with the AspectJ framework.

spring-beans: The base implementation of springIoC (dependency injection).

spring-context.support: Extended support for spring-context for MVC aspects.

spring-context: spring provides extended services on basic IoC functions, and also provides support for many enterprise-level services, such as mail services, task scheduling, JNDI positioning, EJB integration, remote access, caching, and encapsulation of various view layer frameworks Wait.

spring-core: The core toolkit for spring 3.1.

spring-expression: The spring expression language.

spring-instrument.tomcat: Spring 3.1 is the basis for Tomcat's connection pool.

spring-instrument: Spring3.1's proxy interface to the server.

spring-jdbc: Spring's simple encapsulation of JDBC.

spring-jms: A simple package made by spring to simplify the use of the JMS API.

spring-orm: spring integrates third-party ORM (object-relational mapping) mapping support, such as Hibernate, Ibatis, Jdo, and spring's JPA support.

spring-oxm: Spring's support for Object/XMI mapping allows switching back and forth between JAVA and XML.

spring-test: Spring's simple encapsulation of testing frameworks such as Junit.

spring-transaction: Consistent declarative and programmatic transaction management for JDBC, Hibernate, JDO, JPA, and more.

spring-web.portlet: enhancements to springMVC.

spring-web.servlet: Support for J2EE6.0 Servlet3.0.

spring-web.struts: Integrate Struts support.

spring-web: Toolkit under springWeb.

Spring Security: Formerly known as Acegi Security, it is a framework used by the Spring project team to provide security authentication services.　

spring-module: Validation framework for form validation.

• Servlet-api ~ not much to say.
• The Shiro~ permission framework is similar to SpringSecurity.
• SiteMesh of sitemesh~OS (OpenSymphony) is a framework component used to implement page layout and decoration in JSP, which can help website developers to easily separate dynamic content and static decoration appearance in pages.
• SLF4J, the Simple Logging Facade for Java, is not a specific logging solution, it only serves a variety of logging systems.
•Spymemcached~ an asynchronous, single-threaded Memcached client developed in Java.
•StAX~ (Streaming API for XML) is a stream-oriented pull parsing XML, which is fast and takes up less resources, and is very suitable for processing XML files with large amounts of data.
• Standard~ is used with jstl to implement the el language. If you want to use JSTL and EL expressions in your project, then you must import this standard.jar file.
• Struts~MVC design pattern application framework, not much to say.
• Struts Menu~ is a tag library used to generate page navigation menus and requires struts support.
• Urlrewritefilter~ is a web filter for rewriting URLs, similar to Apache's mod_rewrite.
• Velocity is a java-based template engine (template engine). It allows anyone to simply use a template language to refer to objects defined by java code. When Velocity is applied to web development, interface designers and java program developers can simultaneously develop a web site that follows the MVC architecture, that is, page designers can only focus on the display effect of the page, while java program developers focus on business logical coding. Velocity separates the java code from the web page, which facilitates the long-term maintenance of the web site, and also provides us with an optional solution besides JSP and PHP.
•Woodstox~ a fast open source XML processor that complies with the StAX (STreaming Api for Xml processing) specification (being a processor means it can handle input (equivalent to parsing) and output (equivalent to writing, serialization)) .
•wsdl4j~ As the name suggests, it is a JAVA class library (toolkit) that parses and creates WSDL.
•Xalan~ It is an XSLT processing package used to convert XML documents into HTML documents, text files TXT, or XML documents in other formats. It implements the interfaces of XSLT1.0 and XPath1.0, and can be invoked on the command line, or in applet, servlet, or as a module of other programs.
• XmlResolver~ to resolve external DTDs, entities and schemas.
•xmlschema~ As the name suggests, it is used to parse xml schema.
• xml-apis.jar and xercesImpl.jar~ These two jars are an extensible markup language (XML) compatible parser.