如何运行由Maven编译的程序？

Question

I am starting to learn Maven by reading https://spring.io/guides/gs/maven/ .

In the examples, after running mvn compile successfully, how can I run the program via maven? This part seems missing from the article.

Thanks.

Answer 1

You can invoke a Java program (ie with a public static void main(String[] args) signature) with the classpath of the combined dependencies for the current pom.xml using

mvn -q exec:java

You need to configure the main class to invoke in your pom.xml similar to

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.6.0</version>
            <executions>
                <execution>
                    <goals>
                        <goal>java</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <mainClass>demo.Main</mainClass>
            </configuration>
        </plugin>
    </plugins>
</build>

This is useful for testing and development, but not deployment

See http://www.mojohaus.org/exec-maven-plugin/usage.html for full details.

Answer 2

Generally, maven is not used for running code. This is a build tool that you can use for compiling, running unit or integration tests, deploying you your code locally and remotely, etc..

It is based around the idea of a build lifecycle where which is in its turn is defined by a list of build phases. For example, the default lifecycle has the following phases:

• validate - validate the project is correct and all necessary information is available
• compile - compile the source code of the project
• test - test the compiled source code using a suitable unit testing framework. These tests should not require the code be packaged or deployed
• package - take the compiled code and package it in its distributable format, such as a JAR.
• verify - run any checks on results of integration tests to ensure quality criteria are met
• install - install the package into the local repository, for use as a dependency in other projects locally
• deploy - done in the build environment, copies the final package to the remote repository for sharing with other developers and projects.

For more information you can refer to this .

UPDATE :

Having said that, it is possible as mentioned in Thorbjørn Ravn Andersen answer here.

Answer 3

The Maven build process has a number of lifecycles, or points in the process. compile is one of the build steps, but most likely running the following would resolve your issue:

mvn clean package

This would generate a JAR file, in the folder where you ran it. You can then try running this JAR file using java .