How to create a manifest file with Maven

﹏ヽ暗。殇╰゛Y 2022-05-26 07:43 404阅读 0赞

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This tutorial will show you how to use the `maven-jar-plugin` to create a manifest file, and package / add it into the final jar file. The manifest file is normally used to define following tasks :

1.  Define the entry point of the Application, make the Jar executable.
2.  Add project dependency classpath.

When you run the command `mvn package` to package project into a Jar, the following `meta-inf/manifest.mf` file will be generated and added into the final Jar file automatically.

meta-inf/manifest.mf

Manifest-Version: 1.0
    Built-By: ${user.name}
    Build-Jdk: ${java.version}
    Created-By: Apache Maven
    Archiver-Version: Plexus Archiver

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## 1. Make the Jar executable ##

Define `maven-jar-plugin` in `pom.xml`, and configure the manifest file via configuration tag.

pom.xml

<plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
              <archive>
                <manifest>
                    <mainClass>com.mkyong.core.App</mainClass>
                </manifest>
              </archive>
            </configuration>
        </plugin>

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Following manifest file will be generated. If you run this Jar, it will execute the `com.mkyong.core.App`.

meta-inf/manifest.mf

anifest-Version: 1.0
    Built-By: mkyong
    Build-Jdk: 1.6.0_35
    Created-By: Apache Maven
    Main-Class: com.mkyong.core.App
    Archiver-Version: Plexus Archiver

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## 2. Add project dependency classpath. ##

Most Java projects need dependency, and it can define in manifest file easily. Normally, you will use `maven-dependency-plugin` to copy project dependencies to somewhere else.

pom.xml

<plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
              <archive>
                <manifest>
                    <addClasspath>true</addClasspath>
                    <mainClass>com.mkyong.core.App</mainClass>
                    <classpathPrefix>dependency-jars/</classpathPrefix>
                </manifest>
              </archive>
            </configuration>
      </plugin>
      <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>2.5.1</version>
            <executions>
              <execution>
                    <id>copy-dependencies</id>
                    <phase>package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>
                              ${project.build.directory}/dependency-jars/
                        </outputDirectory>
                    </configuration>
                </execution>
            </executions>
      </plugin>

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Following manifest file will be generated. The project dependencies will be copied to `{project}/target/dependency-jars/`.

meta-inf/manifest.mf

manifest-Version: 1.0
    Built-By: mkyong
    Build-Jdk: 1.6.0_35
    Class-Path: dependency-jars/log4j-1.2.17.jar
    Created-By: Apache Maven
    Main-Class: com.mkyong.core.App
    Archiver-Version: Plexus Archiver

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## Download Source Code ##

Download it –  [Generate-Manifest-Using-Maven.zip][] (7 KB).

## References ##

1.  [Maven manifest references][]
2.  [Maven manifest examples][]
3.  [How to create a Jar file with Maven][]

[Generate-Manifest-Using-Maven.zip]: http://www.mkyong.com/wp-content/uploads/2012/11/Java-project-into-jar-maven.zip
[Maven manifest references]: http://maven.apache.org/shared/maven-archiver/
[Maven manifest examples]: http://maven.apache.org/shared/maven-archiver/examples/classpath.html
[How to create a Jar file with Maven]: http://www.mkyong.com/maven/how-to-create-a-jar-file-with-maven/