Maven

Posted 2020-09-15 架构成长之路

maven安装

下载安装包，maven官网

配置环境变量

MAVEN_HOME = D:\\hnisi\\local\\apache-maven-3.0.4

PATH=%PATH%;%MAVEN_HOME%\\bin

MAVEN_OPTS = -Xms128m -Xmx512m

M2_HOME = D:\\hnisi\\local\\apache-maven-3.0.4

maven依赖冲突

maven是最先声明原则来引用相应版本的jar，而gradle是最新版本原则。

首先要定位错误的jar包，在项目启动时加上vm参数-verbose:class，这时会打印类似如下信息：

[Loaded java.util.TaskQueue from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.TimerThread from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.Timer$1 from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded org.quartz.impl.StdScheduler from file:/Users/lilu/repository/org/quartz-scheduler/quartz/2.2.1/quartz-2.2.1.jar]
[Loaded java.util.Hashtable$KeySet from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded org.quartz.SchedulerMetaData from file:/Users/lilu/repository/org/quartz-scheduler/quartz/2.2.1/quartz-2.2.1.jar]
[Loaded java.util.TreeMap$NavigableSubMap from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.TreeMap$AscendingSubMap from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.TreeMap$NavigableSubMap$EntrySetView from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.TreeMap$AscendingSubMap$AscendingEntrySetView from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.TreeMap$NavigableSubMap$SubMapIterator from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.TreeMap$NavigableSubMap$SubMapEntryIterator from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded org.quartz.simpl.JobWrapper from file:/Users/lilu/repository/org/quartz-scheduler/quartz/2.2.1/quartz-2.2.1.jar]
[Loaded org.quartz.simpl.TriggerWrapper from file:/Users/lilu/repository/org/quartz-scheduler/quartz/2.2.1/quartz-2.2.1.jar]
[Loaded sun.util.locale.provider.TimeZoneNameUtility from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded sun.util.locale.provider.TimeZoneNameProviderImpl from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded sun.util.locale.provider.TimeZoneNameUtility$TimeZoneNameGetter from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded sun.util.resources.TimeZoneNamesBundle from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded sun.util.resources.TimeZoneNames from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded sun.util.resources.en.TimeZoneNames_en from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
[Loaded java.util.LinkedHashMap$LinkedKeySet from /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar]
group_1.testJob_1 运行在: Sun Apr 30 08:41:57 CST 2017
[Loaded org.quartz.DisallowConcurrentExecution from file:/Users/lilu/repository/org/quartz-scheduler/quartz/2.2.1/quartz-2.2.1.jar]
[Loaded org.quartz.utils.ClassUtils f

maven的pom.xml会显示或隐式的依赖类包，如果不想依赖某个类包，可以通过用exclusion排除之，如下：

<dependency>  
        <groupId>org.unitils</groupId>  
        <artifactId>unitils-testng</artifactId>  
        <version>${unitils.version}</version>  
        <scope>test</scope>  
        <exclusions>  
            <exclusion>  
                <artifactId>junit</artifactId>  
                <groupId>junit</groupId>  
            </exclusion>  
        </exclusions>  
</dependency>  

maven仓库

maven仓库主要有两种：

• remote repository：相当于公共的仓库，大家都能访问到，一般可以用URL的形式访问

• local repository：存放在本地磁盘的一个文件夹，例如，windows上默认是C:\\Users\\｛用户名｝\\.m2\\repository目录

repository里存放的都是各种jar包和maven插件。当向仓库请求插件或依赖的时候，会先检查local repository，如果local repository有则直接返回，否则会向remote repository请求，并缓存到local repository。也可以把做的东西放到本地仓库，仅供本地使用；或上传到远程仓库，供大家使用。 

maven mirror:

mirror相当于一个拦截器，它会拦截maven对remote repository的相关请求，把请求里的remote repository地址，重定向到mirror里配置的地址。

通过以下图解：

没有配置mirror

配置mirror

此时，B Repository被称为A Repository的镜像。

如果仓库X可以提供仓库Y存储的所有内容，那么就可以认为X是Y的一个镜像。换句话说，任何一个可以从仓库Y获得的构件，都能够从它的镜像中获取。

maven命令

mvn deploy:deploy-file -DgroupId=com.hnisi.syj -DartifactId=acegi-security -Dversion=1.0.5 -Dpackaging=jar 
-Dfile=D://hnisi/workspace/publicservice/WebRoot/WEB-INF/lib/acegi-security-1.0.5.jar 
-Durl=http://xx/nexus/content/repositories/syj-releases/ -DrepositoryId=syj-rxx