Maven(2)_创建第一个Maven项目

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参考Maven Tutorial，Maven - 创建项目

Installing Maven

To install Maven on your own system (computer), go to the Maven download page and follow the instructions there. In summary, what you need to do is:

  1. Set the JAVA_HOME environment variable to point to a valid Java SDK (e.g. Java 8).
  2. Download and unzip Maven.
  3. Set the M2_HOME environment variable to point to the directory you unzipped Maven to.
  4. Set the M2 environment variable to point to M2_HOME/bin (%M2_HOME%\bin on Windows, $M2_HOME/bin on unix).
  5. Add M2 to the PATH environment variable (%M2% on Windows, $M2 on unix).
  6. Open a command prompt and type ‘mvn -version’ (without quotes) and press enter.

Manual project creation

创建项目目录和pom文件

创建pom.xml文件如下：

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


    <groupId>com.jenkov</groupId>

    <artifactId>hello-world</artifactId>

    <version>1.0.0</version>

</project>

可以通过mvn clean测试pom.xml以及环境是否正常：

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pc-a375-2:maven admin$ mvn clean
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building hello-world 1.0.0
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ hello-world ---
Downloading: https://repo.maven.apache.org/maven2/org/codehaus/plexus/plexus-utils/3.0/plexus-utils-3.0.pom
Downloaded: https://repo.maven.apache.org/maven2/org/codehaus/plexus/plexus-utils/3.0/plexus-utils-3.0.pom (4 KB at 1.9 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/sonatype/spice/spice-parent/16/spice-parent-16.pom
Downloaded: https://repo.maven.apache.org/maven2/org/sonatype/spice/spice-parent/16/spice-parent-16.pom (9 KB at 31.8 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/sonatype/forge/forge-parent/5/forge-parent-5.pom
Downloaded: https://repo.maven.apache.org/maven2/org/sonatype/forge/forge-parent/5/forge-parent-5.pom (9 KB at 31.7 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/maven-plugin-api/2.0.6/maven-plugin-api-2.0.6.jar
Downloading: https://repo.maven.apache.org/maven2/org/codehaus/plexus/plexus-utils/3.0/plexus-utils-3.0.jar
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/maven-plugin-api/2.0.6/maven-plugin-api-2.0.6.jar (13 KB at 26.2 KB/sec)
Downloaded: https://repo.maven.apache.org/maven2/org/codehaus/plexus/plexus-utils/3.0/plexus-utils-3.0.jar (221 KB at 292.8 KB/sec)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.157 s
[INFO] Finished at: 2016-04-12T17:39:37+09:00
[INFO] Final Memory: 7M/130M
[INFO] ------------------------------------------------------------------------
pc-a375-2:maven admin$

创建源码目录

按照maven的标准目录结构在项目录下创建源码目录：

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src
  main
    java

创建代码文件

创建java类源码文件HelloWorld.java.

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package helloworld;

public class HelloWorld {

	public static void main(String args[]){

		System.out.println("Hello World, Maven");

	}

}

构建项目

运行mvn package, package是默认生命周期的一个阶段。会将编译得到的java class文件打包位一个JAR文件。maven会创建target目录，生成的JAR文件就在里面。JAR包会命名为：
artifactId-version.

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pc-a375-2:maven admin$ cd target
pc-a375-2:target admin$ ls
classes			hello-world-1.0.0.jar	maven-archiver		maven-status
pc-a375-2:target admin$

项目模板

Archetype 是一个 Maven 插件，它的任务是按照项目模板创建一个项目的目录结构。这里，我们将使用 archetype 插件 quickstart 来创建一个简单的 java 应用。

可以Maven的archetype插件来创建基本的项目，也可以创建高级的项目（根据模板）。要创建一个简单的java应用，我们将使用maven-archetype-quickstart插件。

Maven 将会开始处理，并且要求你选择需要的archetype。

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[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'archetype'.
[INFO] -------------------------------------------------------------------
[INFO] Building Maven Default Project
[INFO]    task-segment: [archetype:generate] (aggregator-style)
[INFO] -------------------------------------------------------------------
[INFO] Preparing archetype:generate
...
600: remote -> org.trailsframework:trails-archetype (-)
601: remote -> org.trailsframework:trails-secure-archetype (-)
602: remote -> org.tynamo:tynamo-archetype (-)
603: remote -> org.wicketstuff.scala:wicket-scala-archetype (-)
604: remote -> org.wicketstuff.scala:wicketstuff-scala-archetype 
Basic setup for a project that combines Scala and Wicket,
depending on the Wicket-Scala project. 
Includes an example Specs test.)
605: remote -> org.wikbook:wikbook.archetype (-)
606: remote -> org.xaloon.archetype:xaloon-archetype-wicket-jpa-glassfish (-)
607: remote -> org.xaloon.archetype:xaloon-archetype-wicket-jpa-spring (-)
608: remote -> org.xwiki.commons:xwiki-commons-component-archetype 
(Make it easy to create a maven project for creating XWiki Components.)
609: remote -> org.xwiki.rendering:xwiki-rendering-archetype-macro 
(Make it easy to create a maven project for creating XWiki Rendering Macros.)
610: remote -> org.zkoss:zk-archetype-component (The ZK Component archetype)
611: remote -> org.zkoss:zk-archetype-webapp (The ZK wepapp archetype)
612: remote -> ru.circumflex:circumflex-archetype (-)
613: remote -> se.vgregion.javg.maven.archetypes:javg-minimal-archetype (-)
614: remote -> sk.seges.sesam:sesam-annotation-archetype (-)
Choose a number or apply filter 
(format: [groupId:]artifactId, case sensitive contains): 203:

按回车选择默认的选项（203：maven-archetype-quickstart）。

Maven 将要求提供 archetype 的特定版本。

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Choose org.apache.maven.archetypes:maven-archetype-quickstart version:
1: 1.0-alpha-1
2: 1.0-alpha-2
3: 1.0-alpha-3
4: 1.0-alpha-4
5: 1.0
6: 1.1
Choose a number: 6:

按回车选择默认的选项（6：maven-archetype-quickstart:1.1）。

Maven 将要求提供项目详情。要找要求键入项目详情。如果默认值有提供就按回车。你可以键入你自己的值来覆盖这些默认值。

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Define value for property 'groupId': : com.companyname.insurance
Define value for property 'artifactId': : health
Define value for property 'version': 1.0-SNAPSHOT:
Define value for property 'package': com.companyname.insurance:
Maven 会要求确认项目详情。按回车或者 Y 。

Confirm properties configuration:
groupId: com.companyname.insurance
artifactId: health
version: 1.0-SNAPSHOT
package: com.companyname.insurance
Y:

现在 Maven 将开始创建项目目录结构并且显示下面的信息：

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[INFO] -----------------------------------------------------------------------
[INFO] Using following parameters for creating project 
from Old (1.x) Archetype: maven-archetype-quickstart:1.1
[INFO] -----------------------------------------------------------------------
[INFO] Parameter: groupId, Value: com.companyname.insurance
[INFO] Parameter: packageName, Value: com.companyname.insurance
[INFO] Parameter: package, Value: com.companyname.insurance
[INFO] Parameter: artifactId, Value: health
[INFO] Parameter: basedir, Value: C:\MVN
[INFO] Parameter: version, Value: 1.0-SNAPSHOT
[INFO] project created from Old (1.x) Archetype in dir: C:\MVN\health
[INFO] -----------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] -----------------------------------------------------------------------
[INFO] Total time: 4 minutes 12 seconds
[INFO] Finished at: Fri Jul 13 11:10:12 IST 2012
[INFO] Final Memory: 20M/90M
[INFO] -----------------------------------------------------------------------

Maven使用如下所示的一套标准目录结构：

目录结构 描述
src/main/java 包含包下的Java源代码文件。
src/main/test 包含包下的测试Java源代码文件。
src/main/resources 包含图片和properties文件（在上面的例子中，我们需要手动创建此目录）。 
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Maven 为项目生成了一个 POM.xml 文件，如下所示：

<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.companyname.insurance</groupId>
   <artifactId>health</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>health</name>
   <url>http://maven.apache.org</url>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
   </dependencies>
</project>

Maven还创建了一个Java源文件样例和Java测试类文件。

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package com.companyname.insurance;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Unit test for simple App.
 */
public class AppTest 
    extends TestCase
{
    /**
     * Create the test case
     *
     * @param testName name of the test case
     */
    public AppTest( String testName )
    {
        super( testName );
    }

    /**
     * @return the suite of tests being tested
     */
    public static Test suite()
    {
        return new TestSuite( AppTest.class );
    }

    /**
     * Rigourous Test :-)
     */
    public void testApp()
    {
        assertTrue( true );
    }
}

开发者需要按照上面表格提到的要求放置自己的文件，然后Maven会处理构建相关的所有复杂工作。

在 Maven 中使用一条命令，你就可以创建任意种类的项目，并且可以迅速启动你的开发工作。