java - 插件org.jacoco :jacoco-maven-plugin: one of its dependencies could not be resolved:

Question

我正在开发 SAML One Login Toolkit，并从 GitHub 获取了最新的主分支 here并使用 Eclipse Oxygen。它应该手动解决所有 Maven 依赖项，但不幸的是事实并非如此。我多次尝试删除 .m2 存储库，但这对我没有帮助。我也尝试过maven强制更新。我收到以下错误

    Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T21:41:47+05:00)
Maven home: C:\Users\nyousaf\Downloads\java-saml-2.2.0\java-saml-2.2.0\core\EMBEDDED

[INFO] Scanning for projects...
[DEBUG] Extension realms for project com.onelogin:java-saml-core:jar:2.2.0: (none)
[DEBUG] Looking up lifecyle mappings for packaging jar from ClassRealm[plexus.core, parent: null]
[DEBUG] Extension realms for project com.onelogin:java-saml-toolkit:pom:2.2.0: (none)
[DEBUG] Looking up lifecyle mappings for packaging pom from ClassRealm[plexus.core, parent: null]
[DEBUG] === REACTOR BUILD PLAN ================================================
[DEBUG] Project: com.onelogin:java-saml-core:jar:2.2.0
[DEBUG] Tasks:   [compile]
[DEBUG] Style:   Regular
[DEBUG] =======================================================================
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building OneLogin java-saml Toolkit Core 2.2.0
[INFO] ------------------------------------------------------------------------
[DEBUG] Lifecycle default -> [validate, initialize, generate-sources, process-sources, generate-resources, process-resources, compile, process-classes, generate-test-sources, process-test-sources, generate-test-resources, process-test-resources, test-compile, process-test-classes, test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install, deploy]
[DEBUG] Lifecycle clean -> [pre-clean, clean, post-clean]
[DEBUG] Lifecycle site -> [pre-site, site, post-site, site-deploy]
[WARNING] The POM for org.jacoco:jacoco-maven-plugin:jar:0.7.7.201606060606 is missing, no dependency information available
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.187 s
[INFO] Finished at: 2017-11-01T13:33:47+05:00
[INFO] Final Memory: 6M/123M
[INFO] ------------------------------------------------------------------------
[ERROR] Plugin org.jacoco:jacoco-maven-plugin:0.7.7.201606060606 or one of its dependencies could not be resolved: Cannot access central (http://repo1.maven.org/maven2) in offline mode and the artifact org.jacoco:jacoco-maven-plugin:jar:0.7.7.201606060606 has not been downloaded from it before. -> [Help 1]
org.apache.maven.plugin.PluginResolutionException: Plugin org.jacoco:jacoco-maven-plugin:0.7.7.201606060606 or one of its dependencies could not be resolved: Cannot access central (http://repo1.maven.org/maven2) in offline mode and the artifact org.jacoco:jacoco-maven-plugin:jar:0.7.7.201606060606 has not been downloaded from it before.
    at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:128)
    at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getPluginDescriptor(DefaultMavenPluginManager.java:179)
    at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getMojoDescriptor(DefaultMavenPluginManager.java:284)
    at org.apache.maven.plugin.DefaultBuildPluginManager.getMojoDescriptor(DefaultBuildPluginManager.java:241)
    at org.apache.maven.lifecycle.internal.DefaultLifecycleMappingDelegate.calculateLifecycleMappings(DefaultLifecycleMappingDelegate.java:110)
    at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateLifecycleMappings(DefaultLifecycleExecutionPlanCalculator.java:266)
    at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateMojoExecutions(DefaultLifecycleExecutionPlanCalculator.java:217)
    at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateExecutionPlan(DefaultLifecycleExecutionPlanCalculator.java:127)
    at org.apache.maven.lifecycle.internal.DefaultLifecycleExecutionPlanCalculator.calculateExecutionPlan(DefaultLifecycleExecutionPlanCalculator.java:145)
    at org.apache.maven.lifecycle.internal.builder.BuilderCommon.resolveBuildPlan(BuilderCommon.java:96)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:109)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.eclipse.aether.resolution.ArtifactResolutionException: Cannot access central (http://repo1.maven.org/maven2) in offline mode and the artifact org.jacoco:jacoco-maven-plugin:jar:0.7.7.201606060606 has not been downloaded from it before.
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:444)
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifacts(DefaultArtifactResolver.java:246)
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifact(DefaultArtifactResolver.java:223)
    at org.eclipse.aether.internal.impl.DefaultRepositorySystem.resolveArtifact(DefaultRepositorySystem.java:294)
    at org.apache.maven.plugin.internal.DefaultPluginDependenciesResolver.resolve(DefaultPluginDependenciesResolver.java:124)
    ... 27 more
Caused by: org.eclipse.aether.transfer.ArtifactNotFoundException: Cannot access central (http://repo1.maven.org/maven2) in offline mode and the artifact org.jacoco:jacoco-maven-plugin:jar:0.7.7.201606060606 has not been downloaded from it before.
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:391)
    ... 31 more
Caused by: org.eclipse.aether.transfer.RepositoryOfflineException: Cannot access central (http://repo1.maven.org/maven2) in offline mode
    at org.eclipse.aether.internal.impl.DefaultOfflineController.checkOffline(DefaultOfflineController.java:72)
    at org.eclipse.aether.internal.impl.Utils.checkOffline(Utils.java:115)
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:387)
    ... 31 more

Answer 1

如果您使用公司代理且未配置 Maven 代理，则会出现此错误。使用this reference在 Maven 中启用代理设置