1.查看mvn依赖关系
mvn dependency: tree > deps.txt
报错：
[ERROR] Could not find goal '' in plugin org.apache.maven.plugins:maven-dependency-plugin:2.8 among available goals copy, analyze, unpack, list-repositories, resolve, resolve-plugins, build-classpath, list, analyze-dep-mgt, sources, analyze-duplicate, copy-dependencies, unpack-dependencies, go-offline, get, purge-local-repository, properties, analyze-report, tree, analyze-only, help -> [Help 1]
org.apache.maven.plugin.MojoNotFoundException: Could not find goal '' in plugin org.apache.maven.plugins:maven-dependency-plugin:2.8 among available goals copy, analyze, unpack, list-repositories, resolve, resolve-plugins, build-classpath, list, analyze-dep-mgt, sources, analyze-duplicate, copy-dependencies, unpack-dependencies, go-offline, get, purge-local-repository, properties, analyze-report, tree, analyze-only, help
at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getMojoDescriptor (DefaultMavenPluginManager.java:292)
at org.apache.maven.plugin.DefaultBuildPluginManager.getMojoDescriptor (DefaultBuildPluginManager.java:244)
at org.apache.maven.lifecycle.internal.MojoDescriptorCreator.getMojoDescriptor (MojoDescriptorCreator.java:239)
at org.apache.maven.lifecycle.internal.DefaultLifecycleTaskSegmentCalculator.calculateTaskSegments (DefaultLifecycleTaskSegmentCalculator.java:103)
at org.apache.maven.lifecycle.internal.DefaultLifecycleTaskSegmentCalculator.calculateTaskSegments (DefaultLifecycleTaskSegmentCalculator.java:83)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:89)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:192)
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)
原因分析：
找不到插件目标 ‘ ’
解决：
去掉：之后的空格，命令变为：
mvn dependency:tree > deps.txt