springboot源码分析之pom.xml文件
SpringBoot的web项目最简单的配置文件如下:
<!--springboot的父pom文件,可以称为springboot项目的版本仲裁中心--> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.6.RELEASE</version> </parent> <dependencies> <!--springboot项目的web快速启动器--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies>
其中spring-boot-starter-web是这个简单项目的web快速启动器，却没有定义相关的版本信息,显然该启动器的版本信息定义在spring-boot-starter-parent中。即spring-boot-starter-parent是springboot项目的版本仲裁中心。
<!--spring-boot-starter-parent项目的父项目,是springboot项目实际上的版本仲裁中心--> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>2.2.6.RELEASE</version> <relativePath>../../spring-boot-dependencies</relativePath> </parent> <artifactId>spring-boot-starter-parent</artifactId> <packaging>pom</packaging> <name>Spring Boot Starter Parent</name> <description>Parent pom providing dependency and plugin management for applications built with Maven</description> <url>https://projects.spring.io/spring-boot/#/spring-boot-starter-parent</url> <!--项目相关属性的配置--> <properties> <!--项目的编码格式--> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <!--项目的jdk版本--> <java.version>1.8</java.version> <resource.delimiter>@</resource.delimiter> <maven.compiler.source>${java.version}</maven.compiler.source> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.target>${java.version}</maven.compiler.target> </properties> <build> <resources> <!--加载资源的位置,以及资源格式--> <resource> <filtering>true</filtering> <directory>${basedir}/src/main/resources</directory> <includes> <include>**/application*.yml</include> <include>**/application*.yaml</include> <include>**/application*.properties</include> </includes> </resource> <resource> <directory>${basedir}/src/main/resources</directory> <excludes> <exclude>**/application*.yml</exclude> <exclude>**/application*.yaml</exclude> <exclude>**/application*.properties</exclude> </excludes> </resource> </resources> <pluginManagement> <plugins> <plugin> <groupId>org.jetbrains.kotlin</groupId> <artifactId>kotlin-maven-plugin</artifactId> <version>${kotlin.version}</version> <executions> <execution> <id>compile</id> <phase>compile</phase> <goals> <goal>compile</goal> </goals> </execution> <execution> <id>test-compile</id> <phase>test-compile</phase> <goals> <goal>test-compile</goal> </goals> </execution> </executions> <configuration> <jvmTarget>${java.version}</jvmTarget> <javaParameters>true</javaParameters> </configuration> </plugin> <plugin> <artifactId>maven-compiler-plugin</artifactId> <configuration> <parameters>true</parameters> </configuration> </plugin> <plugin> <artifactId>maven-failsafe-plugin</artifactId> <executions> <execution> <goals> <goal>integration-test</goal> <goal>verify</goal> </goals> </execution> </executions> <configuration> <classesDirectory>${project.build.outputDirectory}</classesDirectory> </configuration> </plugin> <plugin> <artifactId>maven-jar-plugin</artifactId> <configuration> <archive> <manifest> <mainClass>${start-class}</mainClass> <addDefaultImplementationEntries>true</addDefaultImplementationEntries> </manifest> </archive> </configuration> </plugin> <plugin> <artifactId>maven-war-plugin</artifactId> <configuration> <archive> <manifest> <mainClass>${start-class}</mainClass> <addDefaultImplementationEntries>true</addDefaultImplementationEntries> </manifest> </archive> </configuration> </plugin> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>exec-maven-plugin</artifactId> <configuration> <mainClass>${start-class}</mainClass> </configuration> </plugin> <plugin> <artifactId>maven-resources-plugin</artifactId> <configuration> <delimiters> <delimiter>${resource.delimiter}</delimiter> </delimiters> <useDefaultDelimiters>false</useDefaultDelimiters> </configuration> </plugin> <plugin> <groupId>pl.project13.maven</groupId> <artifactId>git-commit-id-plugin</artifactId> <executions> <execution> <goals> <goal>revision</goal> </goals> </execution> </executions> <configuration> <verbose>true</verbose> <dateFormat>yyyy-MM-dd'T'HH:mm:ssZ</dateFormat> <generateGitPropertiesFile>true</generateGitPropertiesFile> <generateGitPropertiesFilename>${project.build.outputDirectory}/git.properties</generateGitPropertiesFilename> </configuration> </plugin> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <executions> <execution> <id>repackage</id> <goals> <goal>repackage</goal> </goals> </execution> </executions> <configuration> <mainClass>${start-class}</mainClass> </configuration> </plugin> <plugin> <artifactId>maven-shade-plugin</artifactId> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> <configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.handlers</resource> </transformer> <transformer implementation="org.springframework.boot.maven.PropertiesMergingResourceTransformer"> <resource>META-INF/spring.factories</resource> </transformer> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.schemas</resource> </transformer> <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/> <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"> <mainClass>${start-class}</mainClass> </transformer> </transformers> </configuration> </execution> </executions> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <version>2.2.6.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> </plugin> </plugins> </pluginManagement> </build>
通过上面可以看出,spring-boot-parent-starter项目不是实际的版本定义中心,它依赖与spring-boot-dependencies项目,它其中只是定义了项目的编码格式,项目的编译器版本信息,过滤的资源,自动化插件等。(
可以参看博客 http://springboot.javaboy.org/2019/0413/spring-boot-parent ）
而spring-boot-dependencies作为实际的版本中心其中又包含什么呢？
上图是spring-boot-dependencies中部分内容截图,可以看出spring-boot-dependencies是实际上的版本仲裁中心,只是提供版本的定义信息。
总结: 在springboot项目中,spring-boot-dependencies为实际的版本仲裁中心,其中帮我们定义了诸多常用框架的版本信息,而spring-boot-starter-parent则为我们定义了该项目的默认编译版本为jdk1.8,项目的默认编码格式为utf-8，针对application.properties和application.yml的资源过滤,自动化插件的配置等。
