上一篇文章介绍了springboot依赖版本号管理的几种方式，现在来详细分析一下spring-boot-dependencies、spring-boot-starter-parent、io.spring.platform是如何进行版本号控制的，各自有什么作用和区别。
一、spring-boot-dependencies、spring-boot-starter-parent、io.spring.platform三者是继承关系
1.spring-boot-starter-parent继承spring-boot-dependencies
2.io.spring.platform继承spring-boot-starter-parent
二、spring-boot-dependencies
从继承的源点spring-boot-dependencies开始看
1.pom.xml里的dependencyManagement节点
dependencyManagement节点的作用是统一maven引入依赖JAR包的版本号，可以看出spring-boot-dependencies最重要的一个作用就是对springboot可能用到的依赖JAR包做了版本号的控制管理
2.pom.xml里的pluginManagement节点
pluginManagement节点的作用是统一maven引入插件的版本号，可以看出spring-boot-dependencies另一个作用是对springboot可能用到的插件做了版本号的控制管理
3.pom.xml里的plugins节点
spring-boot-dependencies引入（或覆盖）了三个插件：
maven-help-plugin：用于获取有关项目或系统的帮助信息；这个插件是Maven自带的插件，这里进行了覆盖设置；设置inherited（是否继承）为false；设置phase为generate-resources、goal为effective-pom的配置output
<plugin> <artifactId>maven-help-plugin</artifactId> <inherited>false</inherited> <executions> <execution> <id>generate-effective-dependencies-pom</id> <phase>generate-resources</phase> <goals> <goal>effective-pom</goal> </goals> <configuration> <output>${project.build.directory}/effective-pom/spring-boot-dependencies.xml</output> </configuration> </execution> </executions> </plugin>
xml-maven-plugin：处理XML相关
<plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>xml-maven-plugin</artifactId> <version>1.0</version> <inherited>false</inherited> <executions> <execution> <goals> <goal>transform</goal> </goals> </execution> </executions> <configuration> <transformationSets> <transformationSet> <dir>${project.build.directory}/effective-pom</dir> <stylesheet>src/main/xslt/single-project.xsl</stylesheet> <outputDir>${project.build.directory}/effective-pom</outputDir> </transformationSet> </transformationSets> </configuration> </plugin>
build-helper-maven-plugin：用于设置主源码目录、测试源码目录、主资源文件目录、测试资源文件目录等
<plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>build-helper-maven-plugin</artifactId> <inherited>false</inherited> <executions> <execution> <id>attach-artifacts</id> <phase>package</phase> <goals> <goal>attach-artifact</goal> </goals> <configuration> <artifacts> <artifact> <file>${project.build.directory}/effective-pom/spring-boot-dependencies.xml</file> <type>effective-pom</type> </artifact> </artifacts> </configuration> </execution> </executions> </plugin>
这三个插件共同完成了一件事，将spring-boot-dependencies（springboot在项目里使用到的依赖）输出到XML，并且打包install到仓库。
这些就是spring-boot-dependencies主要的作用了，管理控制依赖版本号，管理控制插件版本号以及引入了3个辅助插件。
三、spring-boot-starter-parent
spring-boot-starter-parent继承spring-boot-dependencies
1.pom.xml里的properties节点
spring-boot-starter-parent在properties节点里添加了一些预设配置
java.version：jdk的版本号
<java.version>1.6</java.version>
resource.delimiter：设定占位符为@
<resource.delimiter>@</resource.delimiter>
project.build.sourceEncoding、project.reporting.outputEncoding：设置编码为UTF-8
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
maven.compiler.source、maven.compiler.target：设置编译打包的jdk版本
<maven.compiler.source>${java.version}</maven.compiler.source> <maven.compiler.target>${java.version}</maven.compiler.target>
2.pom.xml里的dependencyManagement节点
覆盖了spring-boot-dependencies的spring-core依赖引入，去掉了spring-core里的commons-logging依赖
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> <exclusions> <exclusion> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> </exclusion> </exclusions> </dependency>
3.pom.xml里的bulid->resources节点
设置了application.properties配置文件的读取目录在/src/main/resources目录下
<resource> <directory>${basedir}/src/main/resources</directory> <filtering>true</filtering> <includes> <include>**/application*.yml</include> <include>**/application*.yaml</include> <include>**/application*.properties</include> </includes> </resource> <resource> <directory>${basedir}/src/main/resources</directory> <excludes> <exclude>**/application*.yml</exclude> <exclude>**/application*.yaml</exclude> <exclude>**/application*.properties</exclude> </excludes> </resource>
4.pom.xml里的pluginManagement节点
覆盖了spring-boot-dependencies的一些插件版本控制管理：maven-failsafe-plugin、maven-jar-plugin、maven-surefire-plugin、maven-war-plugin、exec-maven-plugin、maven-resources-plugin、git-commit-id-plugin、spring-boot-maven-plugin、maven-shade-plugin
maven-failsafe-plugin：配置了绑定Maven打包时integration-test、verify阶段
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-failsafe-plugin</artifactId> <executions> <execution> <goals> <goal>integration-test</goal> <goal>verify</goal> </goals> </execution> </executions> </plugin>
maven-jar-plugin：添加了启动类配置和扫描默认实现JAR包配置
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <configuration> <archive> <manifest> <mainClass>${start-class}</mainClass> <addDefaultImplementationEntries>true</addDefaultImplementationEntries> </manifest> </archive> </configuration> </plugin>
maven-surefire-plugin：配置了Maven打包时单元测试扫描**/*Tests.java、**/*Test.java类，排除**/Abstract*.java类
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> <configuration> <includes> <include>**/*Tests.java</include> <include>**/*Test.java</include> </includes> <excludes> <exclude>**/Abstract*.java</exclude> </excludes> </configuration> </plugin>
maven-war-plugin：配置了可以没有web.xml文件进行启动；添加了启动类配置和扫描默认实现JAR包配置
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <configuration> <failOnMissingWebXml>false</failOnMissingWebXml> <archive> <manifest> <mainClass>${start-class}</mainClass> <addDefaultImplementationEntries>true</addDefaultImplementationEntries> </manifest> </archive> </configuration> </plugin>
exec-maven-plugin：添加了启动类配置
<plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>exec-maven-plugin</artifactId> <configuration> <mainClass>${start-class}</mainClass> </configuration> </plugin>
maven-resources-plugin：配置了资源占位符为 @
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-resources-plugin</artifactId> <version>2.6</version> <configuration> <delimiters> <delimiter>${resource.delimiter}</delimiter> </delimiters> <useDefaultDelimiters>false</useDefaultDelimiters> </configuration> </plugin>
git-commit-id-plugin：配置了绑定Maven打包修订阶段revision的GIT版本号变化；配了verbose为ture；配置了日期格式为yyyy-MM-dd'T'HH:mm:ssZ；配置了生成GIT .properties文件，文件名为${project.build.outputDirectory}/git.properties
<plugin> <groupId>pl.project13.maven</groupId> <artifactId>git-commit-id-plugin</artifactId> <executions> <execution> <goals> <goal>revision</goal> </goals> </execution> </executions> <configuration> <verbose>true</verbose> <dateFormat>yyyy-MM-dd'T'HH:mm:ssZ</dateFormat> <generateGitPropertiesFile>true</generateGitPropertiesFile> <generateGitPropertiesFilename>${project.build.outputDirectory}/git.properties</generateGitPropertiesFilename> </configuration> </plugin>
spring-boot-maven-plugin：配置了绑定Maven打包repackage阶段插件的使用；配置了启动类
<plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <executions> <execution> <goals> <goal>repackage</goal> </goals> </execution> </executions> <configuration> <mainClass>${start-class}</mainClass> </configuration> </plugin>
maven-shade-plugin：覆盖引入spring-boot-maven-plugin依赖JAR；配置keepDependenciesWithProvidedScope为true；配置createDependencyReducedPom为true；过滤掉META-INF/*.SF、META-INF/*.DSA、META-INF/*.RSA，防止重复引用打包失败；配置绑定Maven打包package阶段shade；
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <version>1.5.4.RELEASE</version> </dependency> </dependencies> <configuration> <keepDependenciesWithProvidedScope>true</keepDependenciesWithProvidedScope> <createDependencyReducedPom>true</createDependencyReducedPom> <filters> <filter> <artifact>*:*</artifact> <excludes> <exclude>META-INF/*.SF</exclude> <exclude>META-INF/*.DSA</exclude> <exclude>META-INF/*.RSA</exclude> </excludes> </filter> </filters> </configuration> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> <configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.handlers</resource> </transformer> <transformer implementation="org.springframework.boot.maven.PropertiesMergingResourceTransformer"> <resource>META-INF/spring.factories</resource> </transformer> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.schemas</resource> </transformer> <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/> <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"> <mainClass>${start-class}</mainClass> </transformer> </transformers> </configuration> </execution> </executions> </plugin>
四、io.spring.platform
io.spring.platform继承spring-boot-starter-parent
1.pom.xml里的properties节点
io.spring.platform一个最大的作用便是将经过集成测试的各类依赖版本号进行整合。
在平时开发中，需要某个JAR包依赖往往是习惯性的找最新版本，或是根据经验选择一个版本；
单对某个JAR包来讲，没有任何问题，但当过多的JAR包依赖整合到一起的时候，就可能会出现各自版本不适配的情况产生，产生BUG漏洞的场景将大大增加；
io.spring.platform所做的事情就是将做过集成测试JAR包依赖整合到一起，大大降低了漏洞出现的可能性。
2.pom.xml里的dependencyManagement节点
覆盖所有父节点里的依赖引入并增加部分新的依赖，使用properties节点里的版本号
3.pom.xml里的plugins节点
覆盖spring-boot-dependencies的插件：maven-help-plugin
maven-help-plugin：
<plugin> <artifactId>maven-help-plugin</artifactId> <executions> <execution> <id>generate-effective-dependencies-pom</id> <phase>generate-resources</phase> <goals> <goal>effective-pom</goal> </goals> <configuration> <output>${project.build.directory}/effective-pom.xml</output> </configuration> </execution> </executions> <inherited>false</inherited> </plugin>
新增的插件：gmavenplus-plugin、build-helper-maven-plugin
gmavenplus-plugin：
<plugin> <groupId>org.codehaus.gmavenplus</groupId> <artifactId>gmavenplus-plugin</artifactId> <version>1.1</version> <executions> <execution> <goals> <goal>execute</goal> </goals> <phase>test</phase> </execution> </executions> <configuration> <scripts> <script>file:///${project.basedir}/src/main/groovyScripts/generateBomPropertiesFile.groovy</script> </scripts> </configuration> <dependencies> <dependency> <groupId>org.codehaus.groovy</groupId> <artifactId>groovy-all</artifactId> <version>2.3.0</version> </dependency> </dependencies> <inherited>false</inherited> </plugin>
build-helper-maven-plugin：
<plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>build-helper-maven-plugin</artifactId> <executions> <execution> <id>attach-artifacts</id> <phase>package</phase> <goals> <goal>attach-artifact</goal> </goals> <configuration> <artifacts> <artifact> <file>${project.build.directory}/platform-bom.properties</file> <type>properties</type> </artifact> </artifacts> </configuration> </execution> </executions> <inherited>false</inherited> </plugin>
这样分析之后，对spring-boot-dependencies、spring-boot-starter-parent、io.spring.platform就有了基本的了解了。
这三者最主要的作用还是管理各类依赖的版本控制。
我们完全可以自己做一个pom来管理springboot的依赖引入版本管理，后续文章会展示。
对于pom里各类插件引入的作用，后续也会详细分析。
最终的目的是做到知其然，知其所以然，这样开发起来才会有大局观。