Maven分离配置、依赖

在用Maven打包项目时，要像Hadoop、Spark、Hive等项目打包之后的文件包含bin、lib、conf之类的文件夹，同时可以动态的修改项目的配置参数，需要如下两步：

在 pom.xml 文件中引入 maven-assembly 插件；

在 assembly.xml 文件中制定各个文件目录。

pom.xml引入maven-assembly插件

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<appendAssemblyId>true</appendAssemblyId>
<descriptors>
<descriptor>src/assembly/assembly.xml</descriptor>
</descriptors>
</configuration>
<executions>
<execution>
<id>maven-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>

然后，是src／assembly／assembly.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.1 http://maven.apache.org/xsd/assembly-1.1.1.xsd"> 
<id>all</id>
<formats>
<format>tar.gz</format>
</formats>
<includeBaseDirectory>false</includeBaseDirectory>

<fileSets>
<fileSet>
<directory>bin</directory>
<outputDirectory>bin</outputDirectory>
<fileMode>755</fileMode>
</fileSet>
<fileSet>
<directory>src/main/resources</directory>
<outputDirectory>conf</outputDirectory>
<fileMode>755</fileMode>
<lineEnding>unix</lineEnding>
<excludes>
<exclude>*.formatted</exclude>
</excludes>
</fileSet>
</fileSets>

<dependencySets>
<dependencySet>
<fileMode>755</fileMode>
<outputDirectory>lib</outputDirectory>
<scope>runtime</scope>
<useProjectArtifact>false</useProjectArtifact>
<excludes>
<exclude>${project.groupId}:${project.artifactId}</exclude>
</excludes>
</dependencySet>
<dependencySet>
<fileMode>755</fileMode>
<outputFileNameMapping>${project.artifactId}.jar</outputFileNameMapping>
<outputDirectory>/lib/</outputDirectory>
<scope>runtime</scope>
<includes>
<include>${project.groupId}:${project.artifactId}</include>
</includes>
</dependencySet>
</dependencySets>
</assembly>

不难发现，我们把打好的程序jar包也放到了 lib目录 中。

执行代码
用这种方法打的jar包，是不包含依赖的jar包和配置文件的。所以，在执行之前需要把依赖的jar包和配置文件加入到 $CLASSPATH 中，Shell脚本如下：

#!/usr/bin/env bash

BIN=`dirname $0`
BIN=`cd $BIN; pwd`
APP_HOME=`dirname $BIN`

JAVA=${JAVA_HOME}/bin/java
CLASSPATH=${APP_HOME}/conf
#JAR=${APP_HOME}/tools.jar

for f in ${APP_HOME}/lib/*.jar; do
CLASSPATH=${CLASSPATH}:$f
done

for f in ${APP_HOME}/*.jar; do
CLASSPATH=${CLASSPATH}:$f
done

MAINCLASS="edu.wzm.joda.JodaDemo"
exec "$JAVA" -classpath $CLASSPATH $MAINCLASS