Maven configuring setting XML details -- properties, repositories

properties

effect ： Corresponding profile List of extended properties . maven Properties and ant The properties in are the same , Can be used to store some values . These values can be in pom.xml Use a marker anywhere in the ${X} To use , here X Is the name of the attribute . There are five different forms of attributes , And they can all be in settings.xml File access .

<!--
1. env.X: Add... Before a variable "env." The prefix of , Will return a shell environment variable . for example ,"env.PATH" It refers to $path environment variable （ stay Windows On is %PATH%）.
2. project.x： It refers to POM The corresponding element value in . for example : <project><version>1.0</version></project> adopt ${project.version} get version Value .
3. settings.x: It refers to settings.xml The value of the corresponding element in . for example ：<settings><offline>false</offline></settings> adopt ${settings.offline} get offline Value .
4. Java System Properties: All can be done through java.lang.System.getProperties() Access properties can be in POM Use this form to access , for example ${java.home}.
5. x: stay <properties/> In the elements , Or set in an external file , With ${someVar} In the form of .
-->
<properties>
<user.install>${user.home}/our-project</user.install>
</properties>

notes ： If it's time to profile To be activated , Can be in pom.xml Use in ${user.install}.

Repositories

effect ： Remote warehouse list , It is maven It is used to fill in a set of remote warehouses used to build the local warehouse of the system .

<repositories>
<!-- Contains information that needs to be connected to the remote warehouse -->
<repository>
<!-- Remote warehouse unique identification -->
<id>codehausSnapshots</id>
<!-- Remote warehouse name -->
<name>Codehaus Snapshots</name>
<!-- How to deal with the download of the released version in the remote warehouse -->
<releases>
<!--true perhaps false Indicates whether the repository is downloading a certain type of component （ Release , Snapshot version ） Turn on . -->
<enabled>false</enabled>
<!-- This element specifies how often updates occur .Maven It's more local POM And remote POM The timestamp . The option here is ：always（ always ）,daily（ Default , everyday ）,interval：X（ here X It's a time interval in minutes ）, perhaps never（ never ）. -->
<updatePolicy>always</updatePolicy>
<!-- When Maven What to do when verifying component validation file fails -ignore（ Ignore ）,fail（ Failure ）, perhaps warn（ Warning ）. -->
<checksumPolicy>warn</checksumPolicy>
</releases>
<!-- How to handle the download of snapshot version in remote warehouse . With releases and snapshots These two sets of configurations ,POM It can be in every single warehouse , Take different strategies for each type of component . for example , Someone may decide to turn on support for snapshot version download for development purposes only . See repositories/repository/releases Elements -->
<snapshots>
<enabled />
<updatePolicy />
<checksumPolicy />
</snapshots>
<!-- Remote warehouse URL, Press protocol://hostname/path form -->
<url>http://snapshots.maven.codehaus.org/maven2</url>
<!-- Type of warehouse layout used to locate and sort components - It can be default（ Default ） perhaps legacy（ Legacy ）.Maven 2 Provides a default layout for its warehouse ; However ,Maven 1.x There is a different layout . We can use this element to specify that the layout is default（ Default ） still legacy（ Legacy ）. -->
<layout>default</layout>
</repository>
</repositories>