fat jar（打包发布自身依赖的jar包）

在公共项目开发了common模块，其中包含了发钉钉消息、时间处理等多种公共方法，现在想要发布到maven仓库给其他应用使用。

其他应用使用过程中发现，引入common模块的依赖后还需要单独引用common内部的其他依赖。

client如果要使用发消息模块的能力，需要引入如下依赖：
pom.xml:

<!-- common内部发消息的依赖 -->
<dependency><groupId>com.dingtalk.open</groupId><artifactId>dingtalk-openapi-sdk</artifactId><version>xxx</version>
</dependency><dependency><groupId>com.alibaba.logistics</groupId><artifactId>logistics-infra-common</artifactId><version>1.0.1-SNAPSHOT</version>
</dependency>

这样使用存在两个问题：
1.client需要手动引入common内部使用的依赖，没有起到统一管理的效果。
2.common升级内部依赖client也要跟着升级，否则可能出现低版本使用高版本依赖的方法，比如：ObjectUtils.allNull() 方法就在 commons-lang3 低版本就没有。

那为什么不直接将common模块所需要依赖都打进去呢？
pom.xml:

<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration><!-- 包名称末尾不跟assemblyId --><appendAssemblyId>false</appendAssemblyId><descriptors><descriptor>assembly.xml</descriptor></descriptors>
</configuration>
</plugin><!-- 打包源码 -->
<plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-source-plugin</artifactId><version>3.0.1</version>
</plugin>
<plugin><artifactId>maven-source-plugin</artifactId><executions><execution><id>attach-sources</id><goals><goal>jar</goal></goals></execution></executions>
</plugin>

assembly.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.0http://maven.apache.org/xsd/assembly-1.1.0.xsd"><id>common.jar</id><formats><format>jar</format></formats><includeBaseDirectory>false</includeBaseDirectory><fileSets><fileSet><directory>${project.build.directory}/classes</directory><outputDirectory>/</outputDirectory><includes><include>**/**</include></includes></fileSet></fileSets><dependencySets><dependencySet><outputDirectory>/</outputDirectory><!-- 忽略自己产生的依赖包 --><useProjectArtifact>false</useProjectArtifact></dependencySet></dependencySets></assembly>

MAC解压：tar -zxvf xx.jar -C test1

依赖展示：

看看现在打包后的结果，确实把common所需要的依赖都打包进去了，client不用再单独引入，但是这样有一个问题，common与client的包有很多都是重复的，有可能发生包冲突等问题，对client端很不友好。

那能不能给common依赖瘦下身？排除掉常用的依赖，只包含特有的依赖。
pom.xml:

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.3.0</version>
<configuration><!-- 包名称末尾不跟assemblyId --><appendAssemblyId>false</appendAssemblyId><descriptors><descriptor>src/assembly/assembly.xml</descriptor></descriptors>
</configuration>
<executions><execution><id>make-assembly</id><phase>package</phase><goals><goal>single</goal></goals></execution>
</executions>
</plugin><!-- 打包源码 -->
<plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-source-plugin</artifactId><version>3.0.1</version>
</plugin>
<plugin><artifactId>maven-source-plugin</artifactId><executions><execution><id>attach-sources</id><goals><goal>jar</goal></goals></execution></executions>
</plugin>

assembly:

<?xml version="1.0" encoding="UTF-8" ?>
<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.0http://maven.apache.org/xsd/assembly-1.1.0.xsd"><id>common.jar</id><formats><format>jar</format></formats><includeBaseDirectory>false</includeBaseDirectory><fileSets><fileSet><directory>${project.build.directory}/classes</directory><outputDirectory>/</outputDirectory><includes><include>**/**</include></includes></fileSet></fileSets><dependencySets><dependencySet><outputDirectory>/</outputDirectory><!-- 忽略自己产生的依赖包 --><useProjectArtifact>false</useProjectArtifact><includes><include>com.aliyun.tair:tairjedis-sdk-singlepath</include></includes><excludes><exclude>javax.annotation:javax.annotation-api</exclude><exclude>log4j:log4j</exclude><exclude>org.slf4j:slf4j-api</exclude><exclude>org.slf4j:jul-to-slf4j</exclude><exclude>ch.qos.logback:logback-classic</exclude><exclude>ch.qos.logback:logback-core</exclude><exclude>org.apache.logging.log4j:log4j-to-slf4j</exclude><exclude>org.apache.logging.log4j:log4j-api</exclude><exclude>org.projectlombok:lombok</exclude><exclude>org.springframework:spring-aop</exclude><exclude>org.springframework:spring-beans</exclude><exclude>org.springframework.boot:spring-boot</exclude><exclude>org.springframework.boot:spring-boot-autoconfigure</exclude><exclude>org.springframework.boot:spring-boot-starter</exclude><exclude>org.springframework.boot:spring-boot-starter-logging</exclude><exclude>org.springframework:spring-context</exclude><exclude>org.springframework:spring-core</exclude><exclude>org.springframework:spring-expression</exclude><exclude>org.springframework:spring-jcl</exclude><exclude>org.yaml:snakeyaml</exclude></excludes></dependencySet></dependencySets></assembly>

依赖展示：

经过上述的打包优化后，打出的common包已经很轻量化了，client使用只需要引入common本身即可。

<dependency><groupId>com.alibaba.logistics</groupId><artifactId>logistics-infra-common</artifactId><version>1.0.1-SNAPSHOT</version>
</dependency>

正常打包

<build><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.8.1</version><configuration><source>1.8</source><target>1.8</target><encoding>UTF-8</encoding><compilerArgument>-parameters</compilerArgument></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-resources-plugin</artifactId><version>3.2.0</version><configuration><encoding>UTF-8</encoding></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-source-plugin</artifactId><version>3.2.0</version><executions><execution><id>attach-sources</id><goals><goal>jar</goal></goals></execution></executions></plugin></plugins>
</build>