Repository

Links#

https://maven.apache.org/settings.html
https://maven.apache.org/guides/mini/guide-deployment-security-settings.html
https://maven.apache.org/guides/mini/guide-mirror-settings.html
https://maven.apache.org/guides/mini/guide-proxies.html

1. Important Points#

local repository:
    ~/.m2/repository

remote repository:
    Maven Central, Nexus, Artifactory, GitHub Packages

settings.xml:
    user/CI side configuration for credentials, mirrors, proxies

2. Repository Types#

Type	Purpose
local	cache on developer machine or CI runner
proxy	cache Maven Central and third-party repos
hosted release	internal release artifacts
hosted snapshot	internal SNAPSHOT artifacts
group	one URL that aggregates multiple repos

3. settings.xml#

<settings>
  <servers>
    <server>
      <id>company-releases</id>
      <username>${env.MAVEN_REPO_USER}</username>
      <password>${env.MAVEN_REPO_PASSWORD}</password>
    </server>
  </servers>

  <mirrors>
    <mirror>
      <id>company-maven</id>
      <mirrorOf>*</mirrorOf>
      <url>https://nexus.example.com/repository/maven-public/</url>
    </mirror>
  </mirrors>
</settings>

server id:
    must match repository id in distributionManagement or repository config

4. distributionManagement#

<distributionManagement>
  <repository>
    <id>company-releases</id>
    <url>https://nexus.example.com/repository/maven-releases/</url>
  </repository>
  <snapshotRepository>
    <id>company-snapshots</id>
    <url>https://nexus.example.com/repository/maven-snapshots/</url>
  </snapshotRepository>
</distributionManagement>

./mvnw -B clean deploy

5. Private Dependency Repository#

<repositories>
  <repository>
    <id>company-public</id>
    <url>https://nexus.example.com/repository/maven-public/</url>
  </repository>
</repositories>

enterprise rule:
    prefer mirror in settings.xml
    avoid scattering repository URLs across many POMs

6. Proxy#

<proxies>
  <proxy>
    <id>corp-proxy</id>
    <active>true</active>
    <protocol>https</protocol>
    <host>proxy.example.com</host>
    <port>8080</port>
  </proxy>
</proxies>

7. TLS / Custom CA#

keytool -importcert \
  -alias company-ca \
  -file company-ca.pem \
  -keystore truststore.jks \
  -storepass changeit

export MAVEN_OPTS="-Djavax.net.ssl.trustStore=$PWD/truststore.jks -Djavax.net.ssl.trustStorePassword=changeit"

do not:
    disable TLS verification
    put truststore password in repository

8. Verify#

./mvnw help:effective-settings
./mvnw dependency:get -Dartifact=org.junit.jupiter:junit-jupiter:5.10.2