Maven：無法獲得幫助目標的工作（清理：幫助，編譯器：幫助等）

Question

我是Maven中的新成員。你知道我做錯了什麼嗎（見下文）？

---

 
mvn -e clean:help. 
+ Error stacktraces are turned on. 
[INFO] Scanning for projects... 
[INFO] Searching repository for plugin with prefix: 'clean'. 
[INFO] ------------------------------------------------------------------------ 
[ERROR] BUILD FAILURE 
[INFO] ------------------------------------------------------------------------ 
[INFO] Required goal not found: clean:help in org.apache.maven.plugins:maven-clean-plugin:2.2 
[INFO] ------------------------------------------------------------------------ 
[INFO] Trace 
org.apache.maven.BuildFailureException: Required goal not found: clean:help in org.apache.maven.plugins:maven-clean-plugin:2.2 
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.getMojoDescriptor(DefaultLifecycleExecutor.java:1867) 
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.segmentTaskListByAggregationNeeds(DefaultLifecycleExecutor.java:462) 
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:175) 
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:328) 

Answer 1

您正在使用的命令行（2.2）上不具有clean:help目標（因爲2.3）插件的版本。試試這個：

mvn org.apache.maven.plugins:maven-clean-plugin:2.4:help 

Answer 2

我想你想：

mvn help:describe -Dcmd=clean 

這給：

[INFO] [help:describe {execution: default-cli}] 
[INFO] 'clean' is a lifecycle with the following phases: 
* pre-clean: Not defined 
* clean: org.apache.maven.plugins:maven-clean-plugin:clean 
* post-clean: Not defined 

的更多細節和例子見here。這同樣適用於compile。

mvn help:describe -Dcmd=compile