introduce

Maven is based on the Project Object Model (POM) and uses a short description to download dependencies, handle dependencies, package, build projects, and more.

Maven’s directory structure

A Maven project must have the following structure, otherwise it cannot be identified as a Maven project. Com.wqlm. test is the package directory for the project, and target is the temporary directory after the project is compiled

src
    -main
        -java
            -com.wqlm.test
    -test
        -java
            -com.wqlm.test
    -resources
target
    -class
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Common build commands

  • Compile the projectmvn compile
  • performThe test case mvn test
  • Packaging projectmvn package
  • Delete target directorymvn clean
  • Install jar packages into the local repositorymvn install

Install jar packages locally

MVN install: install-file-dfile =jar package path -dgroupid =groupId -dartifactid =artifactId -dversion = version -dpackaging =jarCopy the code

Pom – 4.0.0. XML

Maven in the installation directory/lib directory, there is a maven – model – builder – 3.3.9. Jar jar package, After decompression in maven – model – builder – 3.3.9 / org/apache/maven/model in a certain pom – 4.0.0. XML file.

This file is the root POM, from which all POMs implicitly inherit.

There’s a lot in there, so let’s just look at this part of the central warehouse

<repositories> <repository> <! <id>central</id> <name> central Repository</name> <! - this is the official maven central warehouse address - > < url > https://repo.maven.apache.org/maven2 < / url > < layout > default < / layout > < snapshots > <! -- Disable download of snapshot version --> <enabled>false</enabled>
        </snapshots>
    </repository>
</repositories>
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Notice the

central
 line, remember this central, this ID, we’re going to use it later