Maven 依赖

1.依赖的配置

<dependencies>
  	<dependency>
  		<groupId>com.iteye.xujava</groupId>
  		<artifactId>project name</artifactId>
  		<version>1.0.0</version>
  		<!-- 前三个为依赖的基本坐标 -->
  		<type><!-- 依赖的类型 ,对应项目坐标定义的packaging,默认为jar --></type>
  		<scope><!-- 依赖范围 --></scope>
  		<optional><!-- 标记依赖是否可选 --></optional>
  		<exclusions><!-- 用来排除传递性依赖 -->
  			<exclusion>
  			</exclusion>
  		</exclusions>
  	</dependency>
<dependencies>

 

2.依赖的范围

compile:编译依赖范围

test:测试依赖范围

provided:已提供依赖范围，对于编译和测试有效，但在运行时无效，典型例子servlet-api，编译和测试时需要，运行时，容器已提供。

runtime:运行时依赖范围，典型例子是JDBC驱动。

system:系统依赖范围，和provided依赖范围一致。但使用system依赖时必须通过systemPath元素显示地指定依赖文件的路径。由于此类依赖不是通过Maven仓库解析的，而且往往与本机系统绑定，可能造成构建的不可移植。systemPath元素可以引用环境变量，如：

<dependency>
    <groupId>javax.sql</groupId>
    <artifactId>jdbc-stdext</artifactId>
    <version>2.0</version>
    <scope>system</scope>
    <systemPath>${java.home}/lib/rt.jar</systemPath>
</dependency>

 import:导入依赖范围，该依赖范围不会对三种classpath产生实际的影响。

 

3.传递性依赖

依赖范围影响传递性依赖

	compile	test	provided	runtime
compile	compile	-	-	runtime
test	test	-	-	test
provided	provided	-	provided	provided
runtime	runtime	-	-	runtime

4.依赖调解

5.可选依赖，可选依赖不被传递

<dependencies>
  	<dependency>
  		<groupId>mysql</groupId>
  		<artifactId>mysql-connector-java</artifactId>
  		<version>5.1.10</version>
  		<optional>true</optional>
  	</dependency>
  	<dependency>
  		<groupId>postgresql</groupId>
  		<artifactId>postgresql</artifactId>
  		<version>8.4-701.jdbc3</version>
  		<optional>true</optional>
  	</dependency>
  </dependencies>

 

6.排除传递性依赖，如test1依赖于test2的1.0.0版，而工程想引入test2的1.1.0版

<dependencies>
  	<dependency>
  		<groupId>com.iteye.xujava</groupId>
  		<artifactId>test1</artifactId>
  		<version>1.0.0</version>
  		<exclusions>
  			<exclusion>
  				<groupId>com.iteye.xujava</groupId>
  				<artifactId>test2</artifactId>
  			</exclusion>
  		</exclusions>
  	</dependency>
  	<dependency>
  		<groupId>com.iteye.xujava</groupId>
  		<artifactId>test2</artifactId>
  		<version>1.1.0</version>
  	</dependency>
  </dependencies>

 

7.归类依赖,即定义常量，避免重复。如下面POM中Spring的版本号

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.iteye.xujava</groupId>
  <artifactId>account-email</artifactId>
  <version>1.0.0</version>
  <packaging>jar</packaging>

  <name>account-email</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <springframework.version>2.5.6</springframework.version>
  </properties>

  <dependencies>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-core</artifactId>
  		<version>${springframework.version}</version>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-beans</artifactId>
  		<version>${springframework.version}</version>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-context</artifactId>
  		<version>${springframework.version}</version>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring-context-support</artifactId>
  		<version>${springframework.version}</version>
  	</dependency>
  	<dependency>
  		<groupId>javax.mail</groupId>
  		<artifactId>mail</artifactId>
  		<version>1.4.1</version>
  	</dependency>
  	<dependency>
  		<groupId>com.icegreen</groupId>
  		<artifactId>greenmail</artifactId>
  		<version>1.3.1b</version>
  		<scope>test</scope>
  	</dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.9</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

 

8.优化依赖

mvn dependency:list

E:\mavenspace\account-email>mvn dependency:list
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building account-email 1.0.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-dependency-plugin:2.1:list (default-cli) @ account-email ---
[INFO]
[INFO] The following files have been resolved:
[INFO]    aopalliance:aopalliance:jar:1.0:compile
[INFO]    com.icegreen:greenmail:jar:1.3.1b:test
[INFO]    commons-logging:commons-logging:jar:1.1.1:compile
[INFO]    javax.activation:activation:jar:1.1:compile
[INFO]    javax.mail:mail:jar:1.4.1:compile
[INFO]    junit:junit:jar:4.9:test
[INFO]    org.hamcrest:hamcrest-core:jar:1.1:test
[INFO]    org.slf4j:slf4j-api:jar:1.3.1:test
[INFO]    org.springframework:spring-beans:jar:2.5.6:compile
[INFO]    org.springframework:spring-context:jar:2.5.6:compile
[INFO]    org.springframework:spring-context-support:jar:2.5.6:compile
[INFO]    org.springframework:spring-core:jar:2.5.6:compile
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.079s
[INFO] Finished at: Sat Jun 15 20:24:06 CST 2013
[INFO] Final Memory: 7M/107M
[INFO] ------------------------------------------------------------------------

 

mvn dependency:tree

E:\mavenspace\account-email>mvn dependency:tree
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building account-email 1.0.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-dependency-plugin:2.1:tree (default-cli) @ account-email ---
[INFO] com.iteye.xujava:account-email:jar:1.0.0
[INFO] +- org.springframework:spring-core:jar:2.5.6:compile
[INFO] |  \- commons-logging:commons-logging:jar:1.1.1:compile
[INFO] +- org.springframework:spring-beans:jar:2.5.6:compile
[INFO] +- org.springframework:spring-context:jar:2.5.6:compile
[INFO] |  \- aopalliance:aopalliance:jar:1.0:compile
[INFO] +- org.springframework:spring-context-support:jar:2.5.6:compile
[INFO] +- javax.mail:mail:jar:1.4.1:compile
[INFO] |  \- javax.activation:activation:jar:1.1:compile
[INFO] +- com.icegreen:greenmail:jar:1.3.1b:test
[INFO] |  \- org.slf4j:slf4j-api:jar:1.3.1:test
[INFO] \- junit:junit:jar:4.9:test
[INFO]    \- org.hamcrest:hamcrest-core:jar:1.1:test
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.185s
[INFO] Finished at: Sat Jun 15 20:25:16 CST 2013
[INFO] Final Memory: 7M/107M
[INFO] ------------------------------------------------------------------------

 

mvn dependency:analyze

E:\mavenspace\account-email>mvn dependency:analyze
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building account-email 1.0.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-dependency-plugin:2.1:analyze (default-cli) @ account-email >>>

[INFO]
[INFO] --- maven-resources-plugin:2.5:resources (default-resources) @ account-em
ail ---
[debug] execute contextualize
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 2 resources
[INFO]
[INFO] --- maven-compiler-plugin:2.3.2:compile (default-compile) @ account-email
 ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.5:testResources (default-testResources) @ ac
count-email ---
[debug] execute contextualize
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory E:\mavenspace\account-email\src\test\
resources
[INFO]
[INFO] --- maven-compiler-plugin:2.3.2:testCompile (default-testCompile) @ accou
nt-email ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] <<< maven-dependency-plugin:2.1:analyze (default-cli) @ account-email <<<

[INFO]
[INFO] --- maven-dependency-plugin:2.1:analyze (default-cli) @ account-email ---

[WARNING] Unused declared dependencies found:
[WARNING]    org.springframework:spring-core:jar:2.5.6:compile
[WARNING]    org.springframework:spring-beans:jar:2.5.6:compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.150s
[INFO] Finished at: Sat Jun 15 20:25:53 CST 2013
[INFO] Final Memory: 8M/107M
[INFO] ------------------------------------------------------------------------