wap 网站 源码,商贸有限公司门头照片,活动策划,中山公众号平台商场网站建设1. 依赖管理
依赖管理#xff0c;可以将有关依赖项的所有信息放在共同的POM中#xff0c;并对子POM中的工件进行更简单的引用。举个例子#xff1a;
父POM
project......dependencyManagementdependenciesdependencygroupIdgro…1. 依赖管理
依赖管理可以将有关依赖项的所有信息放在共同的POM中并对子POM中的工件进行更简单的引用。举个例子
父POM
project......dependencyManagementdependenciesdependencygroupIdgroup-a/groupIdartifactIdartifact-a/artifactIdversion1.0/versionexclusionsexclusiongroupIdgroup-c/groupIdartifactIdexcluded-artifact/artifactId/exclusion/exclusions/dependencydependencygroupIdgroup-c/groupIdartifactIdartifact-b/artifactIdversion1.0/versiontypewar/typescoperuntime/scope/dependencydependencygroupIdgroup-a/groupIdartifactIdartifact-b/artifactIdversion1.0/versiontypebar/typescoperuntime/scope/dependency/dependencies/dependencyManagement......
/project
两个子POM
project...dependenciesdependencygroupIdgroup-a/groupIdartifactIdartifact-a/artifactId/dependencydependencygroupIdgroup-a/groupIdartifactIdartifact-b/artifactId!-- This is not a jar dependency, so we must specify type. --typebar/type/dependency/dependencies
/projectproject...dependenciesdependencygroupIdgroup-c/groupIdartifactIdartifact-b/artifactId!-- This is not a jar dependency, so we must specify type. --typewar/type/dependencydependencygroupIdgroup-a/groupIdartifactIdartifact-b/artifactId!-- This is not a jar dependency, so we must specify type. --typebar/type/dependency/dependencies
/project
在dependencyManagement区域实际上是根据{groupId, artifactId, type, classifier}来进行依赖匹配的。自从type字段的默认值是jar以后最简单的标识只需要设置{groupId, artifactId}即可。
依赖管理的另一个重要的作用是统一管理控制依赖的版本。这一点不再赘述。
2. 导入依赖
依赖可以继承但是目前只支持单继承可以通过“import”的方式从其它POM中导入依赖。
下面的例子Z导入了X和Y管理的依赖。
projectmodelVersion4.0.0/modelVersiongroupIdmaven/groupIdartifactIdZ/artifactIdpackagingpom/packagingversion1.0/versiondependencyManagementdependenciesdependencygroupIdmaven/groupIdartifactIdX/artifactIdversion1.0/versiontypepom/typescopeimport/scope/dependencydependencygroupIdmaven/groupIdartifactIdY/artifactIdversion1.0/versiontypepom/typescopeimport/scope/dependency/dependencies/dependencyManagement
/project
举个例子
?xml version1.0 encodingUTF-8?
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersionparentgroupIdcom.example/groupIdartifactIddemo-parent/artifactIdversion0.0.1-SNAPSHOT/version/parentgroupIdcom.example/groupIdartifactIddemo001/artifactIdversion0.0.1-SNAPSHOT/versiondependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-web/artifactId/dependency/dependenciesdependencyManagementdependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-dependencies/artifactIdversion2.7.11/versiontypepom/typescopeimport/scope/dependency/dependencies/dependencyManagementbuildpluginsplugingroupIdorg.springframework.boot/groupIdartifactIdspring-boot-maven-plugin/artifactIdconfigurationexcludesexcludegroupIdorg.projectlombok/groupIdartifactIdlombok/artifactId/exclude/excludes/configuration/plugin/plugins/build/project
3. 版本管理插件
Introduction – Versions Maven Plugin
versions插件用于管理、模块、依赖和插件的版。该插件有很多目标为了统一管理父子项目版本号我们这里只用其中三个。
操作很简单首先在父工程中引入versions插件
!-- 父POM中增加插件 --
buildpluginsplugingroupIdorg.codehaus.mojo/groupIdartifactIdversions-maven-plugin/artifactIdversion2.16.2/versionconfigurationgenerateBackupPomsfalse/generateBackupPoms/configuration/plugin/plugins
/build
然后更新父工程的版本号
mvn versions:set -DnewVersion2.0.0-SNAPSHOT //更新整个项目版本 接着把子模块的版本更新成父工程的版本号
mvn versions:update-child-modules 最后提交
mvn versions:commit 4. BOM
对于一个项目来说使用“库”中的一个或多个构件是相当常见的。为了使项目中使用的构件的版本与库中分发的版本保持同步。我们可以创建一个“物料清单”BOM以供其它项目使用。
简单的来讲就是多个项目都需要依赖某些包时为了方便管理版本使得多个项目中引用的某个包的版本保持一致这个时候我们就定义一个“库”在这个库中统一定义包的版本使用的时候只需要导入这个库即可。
举个例子
定义一个库其实就是一个POM
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersiongroupIdcom.test/groupIdartifactIdmytest-bom/artifactIdversion1.0.0/versionpackagingpom/packagingpropertiesproject1Version1.0.0/project1Versionproject2Version1.0.0/project2Version/propertiesdependencyManagementdependenciesdependencygroupIdcom.test/groupIdartifactIdproject1/artifactIdversion${project1Version}/version/dependencydependencygroupIdcom.test/groupIdartifactIdproject2/artifactIdversion${project2Version}/version/dependency/dependencies/dependencyManagement
/project
然后定义两个项目project1和project2
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersionparentgroupIdcom.test/groupIdartifactIdmytest-bom/artifactIdversion1.0.0/version/parentgroupIdcom.test/groupIdartifactIdparent/artifactIdversion1.0.0/versionpackagingpom/packagingdependencyManagementdependenciesdependencygroupIdorg.apache.logging.log4j/groupIdartifactIdlog4j-core/artifactIdversion2.22.0/version/dependency/dependencies/dependencyManagement/project
project1
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersionparentgroupIdcom.test/groupIdartifactIdparent/artifactIdversion1.0.0/version/parentgroupIdcom.test/groupIdartifactIdproject1/artifactIdversion${project1Version}/versionpackagingjar/packagingdependenciesdependencygroupIdorg.apache.logging.log4j/groupIdartifactIdlog4j-core/artifactId/dependency/dependencies
/project
project2
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersionparentgroupIdcom.test/groupIdartifactIdparent/artifactIdversion1.0.0/version/parentgroupIdcom.test/groupIdartifactIdproject2/artifactIdversion${project2Version}/versionpackagingjar/packaging
/project
最后在其它项目中引用project1和project2
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersiongroupIdcom.test/groupIdartifactIduse/artifactIdversion1.0.0/versionpackagingjar/packagingdependencyManagementdependenciesdependencygroupIdcom.test/groupIdartifactIdmytest-bom/artifactIdversion1.0.0/versiontypepom/typescopeimport/scope/dependency/dependencies/dependencyManagementdependenciesdependencygroupIdcom.test/groupIdartifactIdproject1/artifactId/dependencydependencygroupIdcom.test/groupIdartifactIdproject2/artifactId/dependency/dependencies
/project
可以看到使用的时候直接导入这个POM然后按需引用 核心就是在一个公共的pom中定义包的版本和依赖管理然后在使用的时候导入公共pom
假设现在在做一个项目其中有两个子项目在cjs-store-service中需要引用cjs-workflow-provider-api
先定义一个公共的pom
?xml version1.0 encodingUTF-8?
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersiongroupIdcom.example/groupIdartifactIdcjs-dependencies-bom/artifactIdversion1.0.0-SNAPSHOT/versionpackagingpom/packagingpropertiesstore.version0.0.4-SNAPSHOT/store.versionworkflow.version0.0.3-SNAPSHOT/workflow.version/propertiesdependencyManagementdependenciesdependencygroupIdcom.example/groupIdartifactIdcjs-store-provider-api/artifactIdversion${store.version}/version/dependencydependencygroupIdcom.example/groupIdartifactIdcjs-workflow-provider-api/artifactIdversion${workflow.version}/version/dependency/dependencies/dependencyManagement/project
项目中引用
?xml version1.0 encodingUTF-8?
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersionparentgroupIdcom.example/groupIdartifactIdcjs-store/artifactIdversion0.0.4-SNATHOST/version/parentgroupIdcom.example/groupIdartifactIdcjs-store-service/artifactIdversion0.0.4-SNATHOST/versiondependenciesdependencygroupIdcom.example/groupIdartifactIdcjs-store-dto/artifactIdversion${project.parent.version}/version/dependencydependencygroupIdcom.example/groupIdartifactIdcjs-workflow-provider-api/artifactId/dependency/dependencies!-- 如果父工程cjs-store的parent不是cjs-dependencies-bom则这里需要import否则不需要因为可以直接通过继承得到 --dependencyManagementdependenciesdependencygroupIdcom.example/groupIdartifactIdcjs-dependencies-bom/artifactIdversion1.0.0-SNAPSHOT/versiontypepom/typescopeimport/scope/dependency/dependencies/dependencyManagement
/project
其实这种依赖包管理可以学习一下dubbo 5. 项目启动问题
如果你的springboot项目起不来控制台也不打印任何报错信息就像这样 那么你可以在SpringApplication.run()这一行打断点 然后就可以看到报错了
