Maven Index:
============
# Overview of Maven
# Diff b/w Maven and Ant
# Diff b/w Maven and Other build tools
# How to install Maven in Windows
# How to install Maven in Linux
# Maven Architecture
# Maven Goles
# Maven Life Cycle
# Standard Directory Layout
# GAV
# Maven local and remote repositories
# Packages and their types
# Sample Maven Project
# One by one goals executions
# Build in and custom plugins
# POM File
# Maven SNAPSHORT
# Maven profiles
# Maven dependency
Build Tools/Build Automation/Management/Process
================================================
--> Build Management: is a process that we compile and assemble all the source code(written by developers) into object files.
ex: 100 app.java files
100 object files(.class files)
Alternatives
------------
- Grunt
- Gulp
- Ant--> Apache Foundation product
- Gradle--> Alternative for Maven
- Maven--> latest and updated one
Ant vs Maven:
-------------
- actions are defined in ant(so much of scripting) - in maven say what to do not how to do
- sequences are defined in ant - how to build is defined in maven (life cycle)
- no default directory structure - it follows standard directory structure(default)
- ant follows you - you need to follow maven
- librarys are part of source code - librarys are not part of source code
(difficult to maintain)
Diff with other tools(why maven?)
---------------------------------
- open source
- it is not only build tool and also project management tool
- it follows set of standards/rules/protocals
- default project lifecycle
- dependency management
What Maven do
-------------
- Compiling Source Code
- Packaging Biniries/artifacts
- running Automated tests
- Deploying to production system
- Creating Documentation
Variables:
---------
- Variables : variable is a name which holds/stores data.
- user : user defind variables eg:- vmtutes = Vinodh-Machireddy-Tutorials
- system variables. : Already created variables (or) pre-defind variables. eg:- echo $PATH, $HOME, $SHELL...etc
Note:- if we want to use variables globally "export vmtutes = Vinodh-Machireddy-Tutorials" (in bashrc file)
Maven Installation in Windows:
------------------------------
--> install java above 7.1 version
--> Download java JDK & JRE (or) http://www.oracle.com/technetwork/java/javase/downloads/index.html
--> Go to-->mycomputer-->properties-->Advanced system settings-->environment variables-->system variables
--> path ;C:\Program Files\Java\jdk1.8.0_131\bin;C:\Program Files\Java\jre1.8.0_131\bin;D:\Apache_Maven\bin
---> to system variables PATH by seperater ;
JAVA_HOME should point to JDK(without bin)
--> install Maven
Go to this website to downloab(Zip)--> maven.apache.org/download.cgi
D:\Apache_Maven ---> MAVEN_HOME in system variables
path--> ;D:\Apache_Maven\bin
maven installation in ec2
=========================
1. sudo yum update -y
2. - sudo /usr/sbin/alternatives --config java
Note:- it'll show you how many java versions are installed in your machine and you can select which one want to use.
- sudo yum install java-17-openjdk-devel -y
- java and javac (Java Compiler)
- java -version
- which java
- whereis java
- ls -l /usr/bin/java
- ls -l /etc/alternatives/java
- java path ---- /usr/lib/jvm/jre-17-openjdk-17.0.5.0.8-2.el9_0.x86_64/bin/java
- sudo yum list installed | grep java
3. Install Maven in /opt directory
cd /opt
4. Download apache maven
wget https://dlcdn.apache.org/maven/maven-3/3.9.6/binaries/apache-maven-3.9.6-bin.tar.gz
note:- yum install wget -y (by default wget package will not install in redhat Linux)
5. tar -xvzf apache-maven-3.9.0-bin.tar.gz
6. for permanent configuration
vi /etc/profile.d/maven.sh
export MAVEN_HOME=/opt/apache-maven-3.9.6
export PATH=$PATH:$MAVEN_HOME/bin
7. source /etc/profile.d/maven.sh
mvn --version
o/p:- Apache Maven 3.8.7 (1edded0938998edf8bf061f1ceb3cfdeccf443fe; 2018-06-17T19:33:14+01:00)
Maven home: /usr/local/src/apache-maven
Java version: 9.0.4, vendor: Oracle Corporation, runtime: /opt/java/jdk-9.0.4
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "4.17.6-1.el7.elrepo.x86_64", arch: "amd64", family: "unix"
verify whether java/maven is installed or not in CMD prompt by typing below commands
Javac --> compiler
java -->keyword
java -version --> runtime environment
mvn --version
How Maven works:(Architecture)
==============================
Build System
---------------------------
| |
Local Repo | POM.XML(conf file) | Remote Repo
-------------->>| |<<----------------(maintained by Maven opensource Community)
| Maven |
----------------------------
--> it works as a GOALS, internally goals are plugins/jar files which has the future of when and what it has to do
eg:- maven test; ---- then it will go and call test plugin to do testing
--> remote maven repository located in - https://repo.maven.apache.org/maven2
--> local repo located in c:/user/vmtutes --> .M2 --> Repository
--> linux local repo in ls -a (.m2)
1. Dependency lifecycle:
=======================
1. generate-source (.java files)
2. compile -->all .java files into .class files(object files)
3. test ---> Unit test (a peace of code)
4. package --> deliveriable or executable or Artifacts(which contains all)
5. install --> to convey info to maven local repo.(c:/user/vinodh --> .M2 --> Repository)
6. Deploy
- clean :- it deletes all runtime files (it is independent plugin/goal)
- site :- documentation(99% we will not use, very regularly for audits...)
Example
-------
mvn clean
Invokes just clean
mvn clean compile
Clean old builds and execute generate, compile
mvn compile install
Invokes generate, compile, test, install
mvn test clean
Invokes generate, compile, test then clean
Note:
diff source and binary
1. source code which we can customize
2. binary code is a product which we can buy/use directly
2. Standard Directory Layout:
--------------------------
- if you want to work with maven project, then we need to follow the maven standard directory structure through which maven will work.
main-->actual source code, lib files,additinal info, property files....etc
test --> unit testing files
once you start compile, maven will go to src/main folder to compile (what are the files you gave over there)
3. GAV:
=======
how maven identify which plugin to select when we instruct a goal. (G.A.V)
G(groupid) -- string rep company name / group name / business org on which u doing project.
A(artifactid) -- string rep product or deliverable(final output of your product)
V(versionid) -- Major.Minar.Patch/Maintanance( add SNAPSHOT to identify in development)
Note:- How maven knows,where java files,what it has to do,where to keep files and fetch files....etc this all done by below two files
to run maven default life cycle
1)dir structure
2) pom.xml file in dir
mvn archetype:generate
note:- mvn -f pom.xml <goal>
Packages
--------
--> jar - java archive(default package maven uses which contains group of .class files, so we group this to get a particular behaviour)
--> war - web archive - contain group of jar + config + xml (for web based projects)
--> ear - enterprice application
packaging -- build type identified using the packaging element
eg : - pom ,jar(default),war,ear
note: - by keeping pom in packaging element it acts as a parent pom of all the modules.
POM:(conf file)
---------------
Project object model is fundamental unit of work in maven,POM is an xml file that contains information about project and configuration details used by maven to build project. pom conf file contains below list.
@ Describe a project(meta data:- data about data)
@ name and Version, Artifact type,source code location, Dependencies
@ Plugins
@ Profiles(Alternate build configuration)
@ it uses XML by default
Note:- atlest one pom.xml file should be there in product/project
Plugins:-
----------
if we want instruct anything to maven through goals we will do, goals internally have plugins/jar files.
1. Build Plugins : we will use this for entire life cycle
2. Reporting Plugins : create documentation of product (for site phase only)
<build>
<plugins>
<plugin>
1. GAV - how maven identifies plugins
2. when you have to run the plugin
3. how to use plugin(like conn DB, insall, disconnect...etc)
4. what exactly to do
</plugin>
-- plugin 2 infomation
</plugins>
</build>
================================================================================
<project>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<version>1.1</version>
<executions>
<execution>
<id>id.clean</id>
<phase>clean</phase>
<goals>
<goal>run</goal>
</goals>
<configuration>
<tasks>
<echo>hello world=============</echo>
</tasks>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<configuration>
<executable>mvn</executable>
<arguments>--version</arguments>
</configuration>
</plugin>
</plugins>
</build>
</project>
Note:- what plugin we selecting, what syntax(GAV) of plugin, And how to call....
--> maven ant plugin, maven exec plugin....
how to call a individual plugin:
---------------------------------
mvn <GOAL>
mvn <PLUGIN>:<GOAL_NAME>
mvn exec:exec
mvn exec:java
--> mvn <plugin>:<goal> ---> we can call plugin directly without phase/goal
SNAPSHOT:
=========
1. it is under development build (or) dev copy which is not yet finalized(only we will change before releasing to client)
2. other projects are depends on this, if i rebuild the jar name other proj looking for this
Maven Profile:
==============
def:- buid profile is a set of configurationns values which can be used to set or override dafault values of maven build.
using a build profile, you can customize buid for different environments such as production v/s developmennt.
--> some times you want to execute only default plugins not all mentioned in build, at that time we can use.
mvn clean (default)
mvn -Pdemo specify goal(all plugins)
<profiles>
<profile>
<id>demo</id>
<build>
</build>
</profile>
</profiles>
--> profile can activate many types like env, os, settings.xml in repo...etc
<profile>
<id>test</id>
<activation>
<property>
<name>env</name>
<value>test</value>
</property>
</activation>
</profile>
Multy-Module Projects:
======================
- if you have 1000 files in app.java project it is diffcult to maintain, so make modules/components like add, sub, dev of calculater project and copy src,pom file in each.
note: - by keeping pom in packaging it acts as a parent pom of all modules (parent and child relationship)
<modules>
<module>add</module>
<module>sub</module>
</modules>
Maven has 1st class multi-module support
Each maven project creates 1 primary artifact
A parent pom is used to group modules
issues -1:
- executing all modules every time
overcome:
parent and child relationship, by keeping 'pom' file in "packaging"
Ex:-
<groupId>EBU</groupId>
<artifactId>Parent-module</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>Child-jar</module>
<module>child-war</module>
</modules>
Issue-2:
--------
- Dependencies
- adding add.jar to subtract for dependency..
<dependencies>
<dependency>
<groupId>training</groupId>
<artifactId>subtract</artifactId>
<version>1.0 SNAPSHORT</version>
</dependency>
</dependencies>
note:-
<dependencies> |
<dependency> |
<groupId>junit</groupId> |
<artifactId>junit</artifactId> |------------- junit plugin is default plugin for performing test phase
<version>3.8.1</version> |
<scope>test</scope> |
</dependency> |
</dependencies> |
by using "install" phase in add module, then add.jar will move to local repo
mvn install--> copying jar file form local project folder to local repository
giving parent gav in child ==>>complete parent and child rel
Dependencys how maven know:
--------------------------
- if sub is depend on add file then we need to keep add file GAV into sub file dependency.
- error :- not able to find add file, then install add file from local project folder to local repository
mvn install
