通过Maven命令行设置属性

Question

I'm confused about the correct way to set a property for some unit tests via the command line when using Maven. There are a number of questions (eg Specifying Maven memory parameter without setting MAVEN_OPTS environment variable , Is there a way to pass jvm args via command line to maven? , How to set JVM parameters for Junit Unit Tests? ) that touch on this subject but none have the answer I'm looking for.

I want to set the property java.util.logging.config.class to some value but I don't want to set the MAVEN_OPTS environment variable.

I can configure the surefire plugin in my pom file with the property:

<argLine>-Djava.util.logging.config.class=someClass</argLine>

so that it is set every time the test phase is run.

However, if I remove the setting from the pom file and add the following to the command line:

mvn package -DargLine="java.util.logging.config.class=someClass"

then the following error in the test phase is reported and the build fails:

Error: Could not find or load main class java.util.logging.config.class=someClass

If I run the following from the command line:

mvn package -Djava.util.logging.config.class=someClass

then the following error is reported at the beginning of the build but the build and tests are successful:

Logging configuration class "someClass" failed java.lang.ClassNotFoundException: someClass

I don't really understand the behaviour. Can someone enlighten me?

Answer 1

Yes, you should have

mvn package -DargLine="-Djava.util.logging.config.class=someClass"

Notice the addition of -D inside the argLine .

Let's explain why. argLine is indeed an attribute of the maven-surefire-plugin with the corresponding user property argLine . This means that you can set this property directly on the command line with -DargLine . But then, the value of that property is -Djava.util.logging.config.class=someClass . This is exactly what you had when you configured the plugin in the POM directly with

<argLine>-Djava.util.logging.config.class=someClass</argLine>

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Additionally, when you call

mvn package -Djava.util.logging.config.class=someClass

then you are not setting the argLine property. You are adding a system property.

Answer 2

Regarding your approach to configuring tests

If you want to pass in configuration to your tests, use for example a file in src/test/resources/myTestConfig.xml. Or use the enhanced features of Test-ng . Your tests will have no value on the centralized build server, or those who want to run/test your code, where config values can't be changed (easily).

The recommended usage of command-line arguments for Maven is for configuring the Maven plugins, build environment and Java config for the build. Use as little features, config and plugins as possible. Or you'll face a ton of issues down the line, and the tweak-all-you-want-A-standardized-build-doesn't-mean-sh*t-for-me- Gradle will feel more comfortable.