What are the phases of Maven's build lifecycle? How to use Maven commands to execute builds? - 面试题

Maven's Build Lifecycle is a series of ordered phases, each representing a step in the build process. Maven defines three independent lifecycles: clean, default, and site.

1. Clean Lifecycle: Used for cleaning the project, includes three phases:

pre-clean: perform work before cleaning
clean: delete files generated by the previous build (target directory)
post-clean: perform work after cleaning

2. Default Lifecycle: This is the most commonly used lifecycle, includes about 20 phases, main phases include:

validate: validate that the project is correct and all necessary information is available
compile: compile the project's source code
test: test the compiled source code using a suitable unit testing framework
package: package the compiled code into a distributable format (JAR, WAR, etc.)
integration-test: process and deploy the package in an integration environment
verify: run checks to verify the package is valid and meets quality standards
install: install the package into the local repository for use by other local projects
deploy: copy the final package to a remote repository for sharing with other developers and projects

3. Site Lifecycle: Used for generating project site documentation, includes:

pre-site: perform work before generating the site
site: generate project site documentation
post-site: perform work after generating the site
site-deploy: deploy the generated site to a server

Lifecycle Execution Rules:

When executing a phase, all phases before it are automatically executed
Different lifecycles are independent of each other, executing one lifecycle does not affect other lifecycles
Can execute specific phases through mvn phase command, such as mvn clean install

Practical Applications:

Development phase: mvn compile compile code
Testing phase: mvn test run tests
Packaging phase: mvn package package application
Local installation: mvn install install to local repository
Complete build: mvn clean package clean and package
Deployment: mvn deploy deploy to remote repository

Understanding Maven lifecycle is crucial for automated builds, continuous integration, and project deployment.