什么是pom?
pom作为项目对象模型。通过xml表示maven项目,使用pom.xml来实现。主要描述了项目:包括配置文件;开发者需要遵循的规则,缺陷管理系统,组织和licenses,项目的url,项目的依赖性,以及其他所有的项目相关因素。
快速察看:
<project> <modelVersion>4.0.0modelVersion> <groupId>...groupId> <artifactId>...artifactId> <version>...version> <packaging>...packaging> <dependencies>...dependencies> <parent>...parent> <dependencyManagement>...dependencyManagement> <modules>...modules> <properties>...properties> <build>...build> <reporting>...reporting> <name>...name> <description>...description> <url>...url> <inceptionYear>...inceptionYear> <licenses>...licenses> <organization>...organization> <developers>...developers> <contributors>...contributors> <issueManagement>...issueManagement> <ciManagement>...ciManagement> <mailingLists>...mailingLists> <scm>...scm> <prerequisites>...prerequisites> <repositories>...repositories> <pluginRepositories>...pluginRepositories> <distributionManagement>...distributionManagement> <profiles>...profiles> project>
基本内容:
POM包括了所有的项目信息。
maven 相关:
pom定义了最小的maven2元素,允许groupId,artifactId,version。所有需要的元素
POM关系:
主要为依赖,继承,合成
依赖关系:
<dependencies> <dependency> <groupId>junitgroupId> <artifactId>junitartifactId> <version>4.0version> <type>jartype> <scope>testscope> <optional>trueoptional> dependency> ... dependencies>
groupId, artifactId, version:描述了依赖的项目唯一标志
可以通过以下方式进行安装:
<project> <modelVersion>4.0.0modelVersion> <groupId>org.codehaus.mojogroupId> <artifactId>my-parentartifactId> <version>2.0version> <packaging>pompackaging> project>
packaging 类型,需要pom用于parent和合成多个项目。我们需要增加相应的值给父pom,用于子项目继承。主要的元素如下:
<project> <modelVersion>4.0.0modelVersion> <parent> <groupId>org.codehaus.mojogroupId> <artifactId>my-parentartifactId> <version>2.0version> <relativePath>../my-parentrelativePath> parent> <artifactId>my-projectartifactId> project>
relativePath可以不需要,但是用于指明parent的目录,用于快速查询。
dependencyManagement:
用于父项目配置共同的依赖关系,主要配置依赖包相同因素,如版本,scope。
合成(或者多个模块)
一个项目有多个模块,也叫做多重模块,或者合成项目。
如下的定义:
<project> <modelVersion>4.0.0modelVersion> <groupId>org.codehaus.mojogroupId> <artifactId>my-parentartifactId> <version>2.0version> <modules> <module>my-project1<module> <module>my-project2<module> modules> project>
build 设置
主要用于编译设置,包括两个主要的元素,build和report
build
主要分为两部分,基本元素和扩展元素集合
注意:包括项目build和profile build
<project> <build>...build> <profiles> <profile> <build>...build> profile> profiles> project>
基本元素
<build> <defaultGoal>installdefaultGoal> <directory>${basedir}/targetdirectory> <finalName>${artifactId}-${version}finalName> <filters> <filter>filters/filter1.propertiesfilter> filters> ... build>
资源(resources)
你项目中需要指定的资源。如spring配置文件,log4j.properties
<project> <build> ... <resources> <resource> <targetPath>META-INF/plexustargetPath> <filtering>falsefiltering> <directory>${basedir}/src/main/plexusdirectory> <includes> <include>configuration.xmlinclude> includes> <excludes> <exclude>**/*.propertiesexclude> excludes> resource> resources> <testResources> ... testResources> ... build> project>
插件
在build时,执行的插件,比较有用的部分,如使用jdk 5.0编译等等
<project> <build> ... <plugins> <plugin> <groupId>org.apache.maven.pluginsgroupId> <artifactId>maven-jar-pluginartifactId> <version>2.0version> <extensions>falseextensions> <inherited>trueinherited> <configuration> <classifier>testclassifier> configuration> <dependencies>...dependencies> <executions>...executions> plugin> plugins> build> project>
<plugin> <artifactId>maven-antrun-pluginartifactId> <executions> <execution> <id>echodirid> <goals> <goal>rungoal> goals> <phase>verifyphase> <inherited>falseinherited> <configuration> <tasks> <echo>Build Dir: ${project.build.directory}echo> tasks> configuration> execution> executions> plugin>
说明:
插件管理
pluginManagement:插件管理以同样的方式包括插件元素,用于在特定的项目中配置。所有继承于此项目的子项目都能使用。主要定义插件的共同元素
扩展元素集合
主要包括以下的元素:
Directories
用于设置各种目录结构,如下:
<build> <sourceDirectory>${basedir}/src/main/javasourceDirectory> <scriptSourceDirectory>${basedir}/src/main/scriptsscriptSourceDirectory> <testSourceDirectory>${basedir}/src/test/javatestSourceDirectory> <outputDirectory>${basedir}/target/classesoutputDirectory> <testOutputDirectory>${basedir}/target/test-classestestOutputDirectory> ... build>
Extensions
表示需要扩展的插件,必须包括进相应的build路径。
<project> <build> ... <extensions> <extension> <groupId>org.apache.maven.wagongroupId> <artifactId>wagon-ftpartifactId> <version>1.0-alpha-3version> extension> extensions> ... build> project>
Reporting
用于在site阶段输出报表。特定的maven 插件能输出相应的定制和配置报表。
<reporting> <plugins> <plugin> <outputDirectory>${basedir}/target/siteoutputDirectory> <artifactId>maven-project-info-reports-pluginartifactId> <reportSets> <reportSet>reportSet> reportSets> plugin> plugins> reporting>
Report Sets
用于配置不同的目标,应用于不同的报表
<reporting> <plugins> <plugin> ... <reportSets> <reportSet> <id>sunlinkid> <reports> <report>javadocreport> reports> <inherited>trueinherited> <configuration> <links> <link>http://java.sun.com/j2se/1.5.0/docs/api/link> links> configuration> reportSet> reportSets> plugin> plugins> reporting>
独占性
外在告诉maven你只包括指定的项目,不包括相关的依赖。此因素主要用于解决版本冲突问题
<dependencies> <dependency> <groupId>org.apache.mavengroupId> <artifactId>maven-embedderartifactId> <version>2.0version> <exclusions> <exclusion> <groupId>org.apache.mavengroupId> <artifactId>maven-coreartifactId> exclusion> exclusions> dependency>
表示项目maven-embedder需要项目maven-core,但我们不想引用maven-core
继承关系
另一个强大的变化,maven带来的是项目继承。主要的设置:
定义父项目
更多的项目信息
Licenses
<licenses> <license> <name>Apache 2name> <url>http://www.apache.org/licenses/LICENSE-2.0.txturl> <distribution>repodistribution> <comments>A business-friendly OSS licensecomments> license> licenses>
Organization
配置组织信息
<organization> <name>Codehaus Mojoname> <url>http://mojo.codehaus.orgurl> organization>
Developers
配置开发者信息
<developers> <developer> <id>ericid> <name>Ericname> <email>[email protected]> <url>http://eric.propellors.neturl> <organization>Codehausorganization> <organizationUrl>http://mojo.codehaus.orgorganizationUrl> <roles> <role>architectrole> <role>developerrole> roles> <timezone>-6timezone> <properties> <picUrl>http://tinyurl.com/prv4tpicUrl> properties> developer> developers>
Contributors
<contributors> <contributor> <name>Noellename> <email>[email protected]> <url>http://noellemarie.comurl> <organization>Noelle Marieorganization> <organizationUrl>http://noellemarie.comorganizationUrl> <roles> <role>testerrole> roles> <timezone>-5timezone> <properties> <gtalk>[email protected]> properties> contributor> contributors>
环境设置
Issue Management
定义相关的bug跟踪系统,如bugzilla,testtrack,clearQuest等
<issueManagement> <system>Bugzillasystem> <url>http://127.0.0.1/bugzillaurl> issueManagement>
Continuous Integration Management
连续整合管理,基于triggers或者timings
<ciManagement> <system>continuumsystem> <url>http://127.0.0.1:8080/continuumurl> <notifiers> <notifier> <type>mailtype> <sendOnError>truesendOnError> <sendOnFailure>truesendOnFailure> <sendOnSuccess>falsesendOnSuccess> <sendOnWarning>falsesendOnWarning> <configuration><address>[email protected]>configuration> notifier> notifiers> ciManagement>
Mailing Lists
<mailingLists> <mailingList> <name>User Listname> <subscribe>[email protected]> <unsubscribe>[email protected]> <post>[email protected]> <archive>http://127.0.0.1/user/archive> <otherArchives> <otherArchive>http://base.google.com/base/1/127.0.0.1otherArchive> otherArchives> mailingList> mailingLists>
SCM
软件配置管理,如cvs 和svn
<scm> <connection>scm:svn:http://127.0.0.1/svn/my-projectconnection> <developerConnection>scm:svn:https://127.0.0.1/svn/my-projectdeveloperConnection> <tag>HEADtag> <url>http://127.0.0.1/websvn/my-projecturl> scm>
Repositories
配置同setting.xml中的开发库
Plugin Repositories
配置同 repositories
Distribution Management
用于配置分发管理,配置相应的产品发布信息,主要用于发布,在执行mvn deploy后表示要发布的位置
1 配置到文件系统
<distributionManagement> <repository> <id>proficio-repositoryid> <name>Proficio Repositoryname> <url>file://${basedir}/target/deployurl> repository> distributionManagement>
2 使用ssh2配置
<distributionManagement> <repository> <id>proficio-repositoryid> <name>Proficio Repositoryname> <url>scp://sshserver.yourcompany.com/deployurl> repository> distributionManagement>
3 使用sftp配置
<distributionManagement> <repository> <id>proficio-repositoryid> <name>Proficio Repositoryname> <url>sftp://ftpserver.yourcompany.com/deployurl> repository> distributionManagement>
4 使用外在的ssh配置
编译扩展用于指定使用wagon外在ssh提供,用于提供你的文件到相应的远程服务器。
<distributionManagement> <repository> <id>proficio-repositoryid> <name>Proficio Repositoryname> <url>scpexe://sshserver.yourcompany.com/deployurl> repository> distributionManagement> <build> <extensions> <extension> <groupId>org.apache.maven.wagongroupId> <artifactId>wagon-ssh-externalartifactId> <version>1.0-alpha-6version> extension> extensions> build>
5 使用ftp配置
<distributionManagement> <repository> <id>proficio-repositoryid> <name>Proficio Repositoryname> <url>ftp://ftpserver.yourcompany.com/deployurl> repository> distributionManagement> <build> <extensions> <extension> <groupId>org.apache.maven.wagongroupId> <artifactId>wagon-ftpartifactId> <version>1.0-alpha-6version> extension> extensions> build>
repository 对应于你的开发库,用户信息通过settings.xml中的server取得
Profiles
类似于settings.xml中的profiles,增加了几个元素,如下的样式:
<profiles> <profile> <id>testid> <activation>...activation> <build>...build> <modules>...modules> <repositories>...repositories> <pluginRepositories>...pluginRepositories> <dependencies>...dependencies> <reporting>...reporting> <dependencyManagement>...dependencyManagement> <distributionManagement>...distributionManagement> profile> profiles>