Maven Basic Knowledge

🧠 The role of Maven

Dependency management:Manage dependencies quickly and easily
Unified project structure:Provide a standard project structure
Project building:Provides a standard way to build cross-platform projects

🏗️ The structure of the Maven project

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Maven-name/
|--src（source code）
|	|--main（project resource）
|		|--java（java code）
|		|--resource（resource）
|	|--test（test）
|		|--java
|		|--resource
|--pom.xml（dependency management）
|--target（target file(.jar)）

🔄 The build process of the Maven project

Maven follows a standard build lifecycle with predefined phases. The main build phases are:

validate: Validate the project structure and required information
compile: Compile the source code
test: Run unit tests
package: Package compiled code into distributable format (.jar, .war)
install: Install the package into local repository
deploy: Deploy the package to remote repository

Common Maven commands:

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# Compile the project
mvn clean compile

# Run tests
mvn test

# Package the project
mvn clean package

# Install to local repository
mvn install

# Deploy to remote repository
mvn deploy

💡 POM File Configuration

The pom.xml file is the core configuration file for Maven projects. Key elements include:

groupId: Unique identifier for the organization
artifactId: Name of the project
version: Version of the project
dependencies: External libraries required
plugins: Build plugins and configurations

Example POM structure:

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<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.example</groupId>
  <artifactId>my-app</artifactId>
  <version>1.0-SNAPSHOT</version>
  
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

⚖️ Dependency Management

Maven automatically resolves dependencies and their transitive dependencies. Dependencies are declared in the POM file with:

groupId: Organization identifier
artifactId: Library name
version: Library version
scope: Visibility scope (compile, runtime, test, provided)

This eliminates manual JAR file management and ensures consistent versions across the project.