maven定义的一个重要原则

?? 在企业级别的项目中依赖关系比较复杂时必须处理好，各个项目的依赖的关系。

公共项目中POM配置如下：

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<project xmlns="http://maven.apache.org/POM/4.0.0"
?xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
?xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

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?<modelVersion>4.0.0</modelVersion>
?<groupId>com.unutrip.common</groupId>
?<artifactId>unutrip-common-service</artifactId>

??<!---定义生成包的类型-->
?<packaging>jar</packaging>
?<name>unutrip-common-service</name>
?<url>http://XXXXXX:8080/unutrip-common-service</url>

?<parent>
??<groupId>com.unutrip</groupId>
??<artifactId>unutrip-parent</artifactId>
??<version>1.0-SNAPSHOT</version>
?</parent>

<!--?<properties>-->
<!--??<env>develop</env>-->
<!--?</properties>-->

?<dependencies>
??????? <dependency>
??????????? <groupId>org.apache.poi</groupId>
??????????? <artifactId>poi</artifactId>
??????????? <version>3.5-FINAL</version>
??????? </dependency>
??<dependency>

???<groupId>com.unusap</groupId>
???<artifactId>unusap-new-remote-no-tiger</artifactId>
???<version>1.0-SNAPSHOT</version>

?? <!---定义忽略的类库-->
???<exclusions>
????<exclusion>
?????<groupId>commons-lang</groupId>
?????<artifactId>commons-lang</artifactId>
????</exclusion>
????<exclusion>
?????<groupId>commons-collections</groupId>
?????<artifactId>commons-collections</artifactId>
????</exclusion>
????<exclusion>
?????<groupId>org.springframework</groupId>
?????<artifactId>spring-web</artifactId>
????</exclusion>
????<exclusion>
?????<groupId>org.springframework</groupId>
?????<artifactId>spring-aop</artifactId>
????</exclusion>
???</exclusions>
??</dependency>
<!---针对项目的版本变化比较快的项目最好将版本的信息定义在属性元素中，使用时 ${ 版本的名称}-->

??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-core</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-beans</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-context</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-context-support</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-web</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-test</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-aop</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-orm</artifactId>
???<version>${spring.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework</groupId>
???<artifactId>spring-jdbc</artifactId>
???<version>${spring.version}</version>
??</dependency>

??<dependency>
???<groupId>cglib</groupId>
???<artifactId>cglib-nodep</artifactId>
???<version>2.1_3</version>
??</dependency>
??<dependency>
???<groupId>org.apache.struts</groupId>
???<artifactId>struts2-core</artifactId>
???<version>${struts.version}</version>
???<exclusions>
????<exclusion>
?????<groupId>com.sun</groupId>
?????<artifactId>tools</artifactId>
????</exclusion>
???</exclusions>
??</dependency>

??<dependency>
???<groupId>org.apache.struts</groupId>
???<artifactId>struts2-convention-plugin</artifactId>
???<version>${struts.version}</version>
??</dependency>
??<dependency>
???<groupId>org.springframework.security</groupId>
???<artifactId>spring-security-core</artifactId>
???<version>${spring.security.version}</version>
???<exclusions>
????<exclusion>
?????<groupId>org.springframework</groupId>
?????<artifactId>spring-support</artifactId>
????</exclusion>
???</exclusions>
??</dependency>
??<dependency>
???<groupId>org.springframework.security</groupId>
???<artifactId>spring-security-cas-client</artifactId>
???<version>${spring.security.version}</version>
???<exclusions>
????<exclusion>
?????<groupId>org.springframework</groupId>
?????<artifactId>spring-dao</artifactId>
????</exclusion>
???</exclusions>
??</dependency>
??<dependency>
???<groupId>org.springframework.security</groupId>
???<artifactId>spring-security-core-tiger</artifactId>
???<version>${spring.security.version}</version>
??</dependency>
??<dependency>
???<groupId>org.hibernate</groupId>
???<artifactId>hibernate-core</artifactId>
???<version>3.3.2.GA</version>
??</dependency>
??<dependency>
???<groupId>org.slf4j</groupId>
???<artifactId>slf4j-simple</artifactId>
???<version>1.5.2</version>
??</dependency>
??<dependency>
???<groupId>javassist</groupId>
???<artifactId>javassist</artifactId>
???<version>3.4.GA</version>
??</dependency>

??<!--
???<dependency>
???<groupId>org.hibernate</groupId>
???<artifactId>hibernate</artifactId>
???<version>${hibernate.version}</version>
???<exclusions>
???<exclusion>
???<groupId>javax.transaction</groupId>
???<artifactId>jta</artifactId>
???</exclusion>
???<exclusion>
???<groupId>commons-collections</groupId>
???<artifactId>commons-collections</artifactId>
???</exclusion>
???</exclusions>
???</dependency>
??-->

??<dependency>

???<groupId>org.hibernate</groupId>
???<artifactId>hibernate-annotations</artifactId>
???<version>${hibernate.annotation.version}</version>
???<exclusions>
????<exclusion>
?????<groupId>org.hibernate</groupId>
?????<artifactId>hibernate</artifactId>
????</exclusion>
???</exclusions>
??</dependency>

??<dependency>

???<groupId>commons-lang</groupId>
???<artifactId>commons-lang</artifactId>
???<version>2.4</version>
??</dependency>
??<dependency>
???<groupId>commons-beanutils</groupId>
???<artifactId>commons-beanutils</artifactId>
???<version>1.8.0</version>
??</dependency>
??<dependency>
???<groupId>commons-codec</groupId>
???<artifactId>commons-codec</artifactId>
???<version>1.3</version>
??</dependency>
??<dependency>
???<groupId>commons-collections</groupId>
???<artifactId>commons-collections</artifactId>
???<version>3.2</version>
??</dependency>
??<dependency>
???<groupId>org.directwebremoting</groupId>
???<artifactId>dwr</artifactId>
???<version>2.0.3</version>
??</dependency>
??<dependency>
???<groupId>org.apache.ant</groupId>
???<artifactId>ant</artifactId>
???<version>1.7.0</version>
???<scope>compile</scope>
??</dependency>

??<dependency>
???<groupId>org.json</groupId>
???<artifactId>json</artifactId>
???<version>20090211</version>
??</dependency>

??<dependency>
???<groupId>commons-httpclient</groupId>
???<artifactId>commons-httpclient</artifactId>
???<version>3.1</version>
??</dependency>

??<dependency>
???<groupId>net.spy</groupId>
???<artifactId>memcached</artifactId>
???<version>2.0.1</version>
??</dependency>

??<dependency>
???<groupId>net.spy</groupId>
???<artifactId>spy</artifactId>
???<version>2.4</version>
??</dependency>

??<dependency>
??? <groupId>jaxen</groupId>
??? <artifactId>jaxen</artifactId>
??? <version>1.1.1</version>
??? <exclusions>
??? ?<exclusion>
??? ??<groupId>dom4j</groupId>
????<artifactId>dom4j</artifactId>
??? ?</exclusion>
??? ?<exclusion>
??? ??<groupId>jdom</groupId>
????<artifactId>jdom</artifactId>
??? ?</exclusion>
??? ?<exclusion>
??? ??<groupId>xml-apis</groupId>
????<artifactId>xml-apis</artifactId>
??? ?</exclusion>
??? ?<exclusion>
??? ??<groupId>xerces</groupId>
????<artifactId>xercesImpl</artifactId>
??? ?</exclusion>
??? ?<exclusion>
??? ??<groupId>xom</groupId>
????<artifactId>xom</artifactId>
??? ?</exclusion>
??? </exclusions>
??</dependency>

??<dependency>
??? <groupId>opensymphony</groupId>
??? <artifactId>quartz-all</artifactId>
??? <version>1.6.3</version>
??</dependency>
??<dependency>
??? <groupId>javax.servlet</groupId>
??? <artifactId>servlet-api</artifactId>
??? <version>2.3</version>
??? <scope>provided</scope>
??</dependency>
??<dependency>
???<groupId>javax.mail</groupId>
???<artifactId>mail</artifactId>
???<version>1.4</version>
??</dependency>
??<dependency>
???<groupId>com.microsoft.sqlserver</groupId>
???<artifactId>sqljdbc4</artifactId>
???<version>1.0</version>
??</dependency>
?</dependencies>

?<scm>
??<connection>
???scm:cvs:pserver:danson.liu@192.168.2.210:/usr/cvsroot:unutrip-common-service
??</connection>
??<developerConnection>
???scm:cvs:pserver:danson.liu@192.168.2.210:/usr/cvsroot:unutrip-common-service
??</developerConnection>
?</scm>
</project>

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? ?（1）如果项目中依赖的jar以及一些公共的信息必须在父POM中定义，

?? 用于减少其他子项目的POM中定义，这样可以减少项目不同类库依赖的，造成版本的之间的差异 的原因，使 项目比较换乱。

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? （2）将兄弟项目的版本如：hibernate-annonation和hibernate-core的版本必须一致，Spring的各类库中版本必须一致，最好将版本信息定义在属性的配置中。

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查看项目中各个类库的依赖关系：

mvn ? dependency：tree

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maven2在执行eclipse:eclipse，install等命令时，默认不下载sources包。

有两个方法可以获得所依赖包的源码包：

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1、使用命令 mvn dependency:sources

2、增加参数 mvn eclipse:eclipse -DdownloadSources=true

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