Articles - Étudiants SUPINFO
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In this article, you will learn what is maven and how does it help
us to optimize the deployment in the workplace. There is the structure of
this article which will help you to have a first look of it.
1.1 Preview
1.2 What is Maven ?
1.2.1 Define Maven
1.2.2 What is Maven Repository ?
1.3 Why do we use Maven ?
1.3.1 The past years we do not have Maven.
1.3.2 Maven makes directory structure standard
1.3.3 pom.xml - the core of Maven
1.3.4 Advantages
1.3.5 How to use Maven?
1.4 Conclusion
1.5 Bibliography
Maven is an open source project management tool written in pure
Java. Maven uses a concept called Project Object Model (POM) to manage
projects.
POM refers to the engineering object model, that is, the project
is managed as an object, and all project configuration information is
defined in a file called POM.xml.
Through this file Maven can manage the entire life cycle of the
project, including cleanup, compilation, testing, reporting, packaging
war, deployment and more.
1.2.2 What is Maven repository?The Maven repository is used to store all the Jar packages managed
by Maven. Divided into: local repository and central repository.
When the project is compiled, Maven will look for the Jar package
required by the project from the local repository at first. If the local
repository does not exist, then it will go to the central repository of
Maven to download the required Jar package.
1.3.1 The past years we do not have Maven.If we build a project, we need to use a lot of third-party
libraries. For example, to write a Web project using Spring, you need to
introduce a large number of jar packages.
The number of Jars in a project often makes us stunned and messy,
and the relationship between Jar packages is usually complicated. A Jar
package often refers to other Jar packages. The lack of any Jar package
will cause the project to fail to compile.
In the past, when developing projects, programmers often need to
spend more time on the environment of checking the Jar package, which is
especially complex to manage. One less Jar package and one more Jar
package will often report some confusing information errors.
Maven is a tool to help us to build projects automatically. We
just need to tell Maven which Jar packages we need. It will help us
download all the Jars. What is more, maven will greatly improve the
development efficiency.
1.3.2 Maven makes directory structure standard
1.3.3 pom.xml - the core of MavenPom.xml is the core of Maven. Which Jar package you need for your
project, you can configure in pom.xml. When the project is compiled,
Maven reads the file and downloads the corresponding Jar package from
the repository.
Let's talk about the POM configuration details. It's actually
simple to learn. Take a look at the pom.xml:
Maven's coordinates GAV (groupId, artifactId, version) are
configured here, and these are required.
The special thing is that the packaging here is pom. All packages
with submodules are packaged as pom. If the packaging is not configured,
its default value is jar, which means that Maven will make the project a
jar package.
The important part of this configuration is modules. The
submodules included in the example are app-util, app-dao, app-service,
app-war.
When Maven builds the app-parent, it organizes a build order based
on the interdependencies of the submodules, and then builds them one by
one.
Projects built with maven have two characteristics:
Dependency management: To make it easily understand, this feature means that
disparate projects are automatically linked directly through the
pom.xml configuration file, without manually managing and
maintaining dependencies between these projects (including jars).
This is the first feature of maven. Dependency management. Project automatically built: Project construction is a daily work of the deployment
process. Project construction means that package the code which are
written by the developer (marked as war, the web project can be
deployed and packaged as long as it is packaged into a war package).
Of course, this process is not only a package, but also includes the
removal. , compilation, testing, reporting. But the actions are given to maven include packages, and maven
will automatically finish it for you. Instead of doing it manually,
this is the second feature of the maven project that is
automatically built. And that feature can significantly improve the
efficiency of the project deployment. First solve the dependency problem between the three modules
of ABC, then use the parent project to manage and maintain the three
ABC modules (this is called aggregation), as long as they are
configured in the corresponding pom.xml file, we do not need to
manually maintain these relationships.
There are some basic and useful commands.
-
-v: Query the Maven version.
This command is used to check if maven is successfully
installed. After the Maven installation is complete, enter mvn -v at
the command line. If relevant information of maven is output, it
means that the installation is successful. Compile: compile .java files. This command is used to compile java source files into class
files. -
Test: test project
This command is used to execute the test project under the
directory. -
Package: package project
This command is used to mark the project as a jar. -
Clean: This command is used to delete the target
folder.
Install: install project. Put the current project in the local repository of
Maven.
With the help of this article, you will finish your journey in
Maven. The first impression of Maven maybe has been left in your mind. You
will have some basic language in your repository. So try and use Maven in
your workplace and daily studying projects!
Images from
https://pt.slideshare.net/tibor17/maven-and-modularity-basics
http://maven.apache.org/
http://jwebsocket.org/documentation/installation-guide/build-jwebsocket-apache-maven
http://www.programgo.com/article/97292470493/
References from
https://maven.apache.org/guides/getting-started/maven-in-five-minutes.html
https://www.tutorialspoint.com/maven/
https://codesjava.com/maven-pom-xml-file
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