Eclipse错误设置Maven项目进行类练习：检查$ M2_HOME环境变量和mvn脚本匹配

Question

I have found a few related questions on this, but they're all related to Intellij or on Mac OS. I'm on Windows 8.1 and using Eclipse:

Eclipse Java EE IDE for Web Developers. Version: Luna Service Release 2 (4.4.2) Build id: 20150219-0600

Maven 3.3.1

I've set up the "Run As" parameters as directed for the course but I get the following error message when I try to run:

-Dmaven.multiModuleProjectDirectory system propery is not set. Check $M2_HOME environment variable and mvn script match.

My output for mvn -version is as follows, and seems to be correct.

Apache Maven 3.3.1 (cab6659f9874fa96462afef40fcf6bc033d58c1c; 2015-03-13T16:10:27-04:00)

Maven home: C:\\Program Files\\Apache Software Foundation\\apache-maven-3.3.1 Java version: 1.7.0_75, vendor: Oracle Corporation

Java home: C:\\Program Files\\Java\\jdk1.7.0_75\\jre

Default locale: en_CA, platform encoding: Cp1252

OS name: "windows 8.1", version: "6.3", arch: "amd64", family: "windows"

I'm a complete newb when it comes to Maven and Eclipse. Any help is appreciated.

Answer 1

Go to: Window--> Preference --> Java --> Installed JREs --> Edit In the edit Default VM arguments you need to put If you already set the maven home, for Windows machine:

-Dmaven.multiModuleProjectDirectory=M2_HOME

And for Linux and Mac OS X:

-Dmaven.multiModuleProjectDirectory=$M2_HOME

In case you are using Maven 3.x, the variable is named $MAVEN_HOME

-Dmaven.multiModuleProjectDirectory=$MAVEN_HOME

Answer 2

I managed to work out a solution for this.

1) I had to to to run configurations and add an argument to the VM. (Run - Run Configurations - JRE Tab - VM arguments). Enter the following in the text box

 -Dmaven.multiModuleProjectDirectory=%M2_HOME%

You need to use %M2_HOME% or something similar to represent the path to Maven, because when I added my path to that argument directly, it was unable to find it. I think it's because there is a length limit on the argument. My path was

C:\Program Files\Apache Software Foundation\apache-maven-3.3.1

and I got an error stating that it couldn't find the runtime at Program Files\\Apache

2) Set up a system environment variable of called M2_HOME with C:\\Program Files\\Apache Software Foundation\\apache-maven-3.3.1

Control Panel - System and Security - System - Advanced System Settings - Environment Variables - System Variables - New

Answer 3

You're not alone in encountering this. I recently moved to 3.3.1 as well and am encountering this same problem.

This isn't the best answer, but this will probably help you today. Try moving back to the latest 3.2.x. (Currently 3.2.5)

I have a feeling it's related to MNG-5767 and a change that recently made it in. There may be some functionality in an m2e update or it may have something to do with the structure of your maven project. Without more detail, it's going to be difficult to tell.

Answer 4

从https://www.eclipse.org/m2e更新m2eclipse安装将解决此问题。

Answer 5

在下面添加VM参数对我有用-Dmaven.multiModuleProjectDirectory = M2_HOME

Answer 6

Newer version of maven will automatically set the multiModuleProjectDirectory property in the bin/mvn script. This was added here , though I'm not sure how the release number/patching works. You can look for the find_maven_basedir function in that file. If it doesn't exist, try upgrading maven.

Answer 7

Access the following location in eclipse

Window
  Preference
    Java
      Installed JREs

Now edit Default VM arguments and place below arguments according to your OS type.

If Windows,

-Dmaven.multiModuleProjectDirectory=M2_HOME

If Linux,

-Dmaven.multiModuleProjectDirectory=$M2_HOME