实际生产中，我们经常要将maven项目打包成jar，然后直接放入hadoop集群环境中运行。之前对于maven项目的使用走了很多弯路，调试了好久，终于调试通过了。以下将为大家分享一下经验。本文讲解的是打成jar包，不是war包。

首先在pom.xml中添加如下代码（添加插件，使得dependencies与项目源码打成一个jar）：

<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-assembly-plugin</artifactId>
				<version>2.5.5</version>
				<configuration>
					<archive>
						<manifest>

                                                        <!--此处存放运行的主类-->
							<mainClass>org.conan.mymahout.recommendation.svd.SvdRunner</mainClass>
						</manifest>
					</archive>
					<descriptorRefs>

                                                <!--此处固定写法-->
						<descriptorRef>jar-with-dependencies</descriptorRef>
					</descriptorRefs>
				</configuration>
			</plugin>
		</plugins>
</build>

在项目上，右键单击 Run as >> Maven build，在如下图所示的方框位置添加如下：

assembly:assembly

点击apply和run

最终控制台显示如下，表示build成功。

-------------------------------------------------------
Running org.conan.mymahout.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.026 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

[INFO] 
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ myMahout ---
[INFO] Building jar: E:\HadoopWorkPlat\workspace\myMahout\target\myMahout-1.0-SNAPSHOT.jar
[INFO] 
[INFO] <<< maven-assembly-plugin:2.5.5:assembly (default-cli) < package @ myMahout <<<
[INFO] 
[INFO] 
[INFO] --- maven-assembly-plugin:2.5.5:assembly (default-cli) @ myMahout ---
[INFO] Building jar: E:\HadoopWorkPlat\workspace\myMahout\target\myMahout-1.0-SNAPSHOT-jar-with-dependencies.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 32.674 s
[INFO] Finished at: 2018-05-25T17:48:17+08:00
[INFO] Final Memory: 210M/1004M
[INFO] ------------------------------------------------------------------------

最终生成的jar包所在目录在控制台中有显示，如下所示：