Java 无法找到或加载主类 org.apache.maven.wrapper.MavenWrapperMain
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Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain
提问by Yang Luo
I have a spring boot project here: https://github.com/jcasbin/jcasbin-springboot-plugin. I encountered the following error in Travis CI:
我在这里有一个 spring boot 项目：https: //github.com/jcasbin/jcasbin-springboot-plugin。我在 Travis CI 中遇到以下错误：
shell
3.43s$ ./mvnw install -DskipTests=true -Dmaven.javadoc.skip=true -B -V
/home/travis/build/jcasbin/jcasbin-springboot-plugin
Picked up _JAVA_OPTIONS: -Xmx2048m -Xms512m
Error: Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain
The command "eval ./mvnw install -DskipTests=true -Dmaven.javadoc.skip=true -B -V " failed. Retrying, 2 of 3.
It seems that the mvnwcommand fails. This file is generated by my IDE: IntelliJ IDEA 2018.1. I don't know what it is used for and why does it fail?
看来mvnw命令失败了。这个文件是我的IDE生成的：IntelliJ IDEA 2018.1。我不知道它的用途是什么，为什么会失败？
I already fired an issue in Spring Boot's github issues here, but Spring project said it's Maven wrapper's issue and pointed me here. I don't quite understand what it means. Is it a Maven bug? How to fix the error then?
我已经在 Spring Boot 的 github 问题here 中引发了一个问题，但是 Spring 项目说这是 Maven 包装器的问题，并指出我在这里。我不太明白这是什么意思。这是一个Maven错误吗？那么如何修复错误呢？
采纳答案by Phil Webb
You're missing the .mvnfolder in your git repository. You should have a folder called .mvnwhich contains the files wrapper/maven-wrapper.jar, wrapper/maven-wrapper.propertiesand jvm.config. Perhaps you missed it because it's a hidden folder.
您缺少.mvngit 存储库中的文件夹。你应该有一个文件夹，名为.mvn其中包含的文件wrapper/maven-wrapper.jar，wrapper/maven-wrapper.properties和jvm.config。也许你错过了它，因为它是一个隐藏的文件夹。
Try doing git add -f .mvnfrom the command line then commit and push.
尝试git add -f .mvn从命令行执行，然后提交并推送。
回答by user3083339
Phil's answer is correct.
And here is how to create .mvn directory with needed jar inside.
I found the answer here
(https://www.baeldung.com/maven-wrapper)
菲尔的回答是正确的。这里是如何创建 .mvn 目录，其中包含所需的 jar。
我在这里找到了答案（https://www.baeldung.com/maven-wrapper）
If you have maven and you want to make maven wrapper working, you need to setup maven wrapper:
如果你有 maven 并且你想让 maven 包装器工作，你需要设置 maven 包装器：
mvn -N io.takari:maven:wrapper
It should create .mvn directory and put needed jar in it.
它应该创建 .mvn 目录并将所需的 jar 放入其中。
回答by Badmous
i actually did just mvn clean install and it worked, i am actually using older version of spring 2.0 to be specific
我实际上只是做了 mvn clean install 并且它起作用了，我实际上使用的是旧版本的 spring 2.0 来具体
回答by Suraj Muraleedharan
For me, maven-wrapper.jarwas missing inside .mvn/wrapper/directory. I searched in github for maven-wrapper.jar, downloaded it and placed it inside .mvn/wrapper/, it worked !!!
对我来说，maven-wrapper.jar在.mvn/wrapper/目录中丢失了。我在 github 上搜索maven-wrapper.jar，下载并放在里面.mvn/wrapper/，成功了！！！
