ChatGPT解决这个技术问题 Extra ChatGPT

Including dependencies in a jar with Maven

Is there a way to force maven(2.0.9) to include all the dependencies in a single jar file?

I have a project the builds into a single jar file. I want the classes from dependencies to be copied into the jar as well.

Update: I know that I cant just include a jar file in a jar file. I'm searching for a way to unpack the jars that are specified as dependencies, and package the class files into my jar.


A
Alexei Khlebnikov

You can do this using the maven-assembly plugin with the "jar-with-dependencies" descriptor. Here's the relevant chunk from one of our pom.xml's that does this:

  <build>
    <plugins>
      <!-- any other plugins -->
      <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>single</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <descriptorRefs>
            <descriptorRef>jar-with-dependencies</descriptorRef>
          </descriptorRefs>
        </configuration>
      </plugin>
    </plugins>
  </build>

In case any new mvn folks got stuck like me, add the plugin to inside which is inside .
How can I avoid including libraries I don't use in my code? My jar just using SSJ sums up to 10 MB :(
@D.A. Why people leave out relevant (read: pertinent) details like that are beyond me.
@Christian.tucker There's a 2nd jar in the target directory created like this: ./target/example-0.0.1-SNAPSHOT.jar and ./target/example-0.0.1-SNAPSHOT-jar-with-dependencies.jar
Just add one more thing in configuration. Your main class information. fully qualified name
H
Helen

With Maven 2, the right way to do this is to use the Maven2 Assembly Plugin which has a pre-defined descriptor file for this purpose and that you could just use on the command line:

mvn assembly:assembly -DdescriptorId=jar-with-dependencies

If you want to make this jar executable, just add the main class to be run to the plugin configuration:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-assembly-plugin</artifactId>
  <configuration>
    <archive>
      <manifest>
        <mainClass>my.package.to.my.MainClass</mainClass>
      </manifest>
    </archive>
  </configuration>
</plugin>

If you want to create that assembly as part of the normal build process, you should bind the single or directory-single goal (the assembly goal should ONLY be run from the command line) to a lifecycle phase (package makes sense), something like this:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-assembly-plugin</artifactId>
  <executions>
    <execution>
      <id>create-my-bundle</id>
      <phase>package</phase>
      <goals>
        <goal>single</goal>
      </goals>
      <configuration>
        <descriptorRefs>
          <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
        ...
      </configuration>
    </execution>
  </executions>
</plugin>

Adapt the configuration element to suit your needs (for example with the manifest stuff as spoken).


I am trying exactly this, however the plugin is not run and the jar file is not created even though the build executes smoothly. Is there a common pitfall that I might have gotten stuck with?
It's working for me but have a questing. after build now two jars are created one with project artifactid-version and another with artifactid-version-"jar-with-dependencies". But I want only one jar to be build. Is there any other way
@SouvikBhattacharya add <appendAssemblyId>false</appendAssemblyId> to maven-assembly-plugin configutation.
a
abdiel

If you want to do an executable jar file, them need set the main class too. So the full configuration should be.

    <plugins>
            <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
                 <executions>
                     <execution>
                          <phase>package</phase>
                          <goals>
                              <goal>single</goal>
                          </goals>
                      </execution>
                  </executions>
                  <configuration>
                       <!-- ... -->
                       <archive>
                           <manifest>
                                 <mainClass>fully.qualified.MainClass</mainClass>
                           </manifest>
                       </archive>
                       <descriptorRefs>
                           <descriptorRef>jar-with-dependencies</descriptorRef>
                      </descriptorRefs>
                 </configuration>
         </plugin>
   </plugins>

Why is the name of jar appended by "jar-with-dependencies"?! Any workarounds?
@Tina J you can add <appendAssemblyId>false</appendAssemblyId> inside the <configuration> tag to exclude the "-jar-with-dependencies" suffix in the final name.
T
Thomas Jung

There's the shade maven plugin. It can be used to package and rename dependencies (to omit dependency problems on the classpath).


if you don't like jar-with-dependencies as part of the file name.
L
Leslie Li
        <!-- Method 1 -->
        <!-- Copy dependency libraries jar files to a separated LIB folder -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <configuration>
                <outputDirectory>${project.build.directory}/lib</outputDirectory>
                <excludeTransitive>false</excludeTransitive> 
                <stripVersion>false</stripVersion>
            </configuration>
            <executions>
                <execution>
                    <id>copy-dependencies</id>
                    <phase>package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <!-- Add LIB folder to classPath -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <archive>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <classpathPrefix>lib/</classpathPrefix>
                    </manifest>
                </archive>
            </configuration>
        </plugin>


        <!-- Method 2 -->
        <!-- Package all libraries classes into one runnable jar -->
        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <executions>
              <execution>
                <phase>package</phase>
                <goals>
                  <goal>single</goal>
                </goals>
              </execution>
            </executions>
            <configuration>
              <descriptorRefs>
                <descriptorRef>jar-with-dependencies</descriptorRef>
              </descriptorRefs>
            </configuration>
        </plugin>            

The first option is the best for faster rebuilds. assembly-plugin just takes too much time packaging dependencies, which is expected.
I tried the first approach here. In the documentation, it states ""Note: The Class-Path header points to classes or JAR files on the local network, not JAR files within the JAR file or classes accessible over Internet protocols. To load classes in JAR files within a JAR file into the class path, you must write custom code to load those classes." In your Method 1, are you referring people to writing custom jar loaders?
I noticed there was a difference in the copying and unpacking in comparison to the assembly. I kept getting "ClassNotFoundException" when trying to run my jar file for my server. How do you recommend proceeding if using your method 1? I couldn't get mine to work.
Option 2 works for me, thanks!
For option 1 (If you don't want to copy JUnit dependencies to target folder) you must add compile to the maven-dependency-plugin
P
Paul Verest

You can use the newly created jar using a <classifier> tag.

<dependencies>
    <dependency>
        <groupId>your.group.id</groupId>
        <artifactId>your.artifact.id</artifactId>
        <version>1.0</version>
        <type>jar</type>
        <classifier>jar-with-dependencies</classifier>
    </dependency>
</dependencies>

R
Rop

If you (like me) dont particularly like the jar-with-dependencies approach described above, the maven-solution I prefer is to simply build a WAR-project, even if it is only a stand-alone java application you are building:

Make a normal maven jar-project, that will build your jar-file (without the dependencies). Also, setup a maven war-project (with only an empty src/main/webapp/WEB-INF/web.xml file, which will avoid a warning/error in the maven-build), that only has your jar-project as a dependency, and make your jar-project a under your war-project. (This war-project is only a simple trick to wrap all your jar-file dependencies into a zip-file.) Build the war-project to produce the war-file. In the deployment-step, simply rename your .war-file to *.zip and unzip it.

You should now have a lib-directory (which you can move where you want it) with your jar and all the dependencies you need to run your application:

java -cp 'path/lib/*' MainClass

(The wildcard in classpath works in Java-6 or higher)

I think this is both simpler to setup in maven (no need to mess around with the assembly plugin) and also gives you a clearer view of the application-structure (you will see the version-numbers of all dependent jars in plain view, and avoid clogging everything into a single jar-file).


Is it the same as Eclipse "Export as Runnable jar"? Because with this you can choose to "package all dependencies with the JAR", you then get all dependencies in project-lib folder, along your jar.
@FaithReaper -- It might be "the same", I never tried that. But I guess if you use Eclipse, it's not easily scriptable, which is a requirement, if you want to implement an automated build+deploy-pipeline. For example, let Jenkins-server do the build from your git source-repository, or similar.
G
Gili

http://fiji.sc/Uber-JAR provides an excellent explanation of the alternatives:

There are three common methods for constructing an uber-JAR: Unshaded. Unpack all JAR files, then repack them into a single JAR. Pro: Works with Java's default class loader. Con: Files present in multiple JAR files with the same path (e.g., META-INF/services/javax.script.ScriptEngineFactory) will overwrite one another, resulting in faulty behavior. Tools: Maven Assembly Plugin, Classworlds Uberjar Shaded. Same as unshaded, but rename (i.e., "shade") all packages of all dependencies. Pro: Works with Java's default class loader. Avoids some (not all) dependency version clashes. Con: Files present in multiple JAR files with the same path (e.g., META-INF/services/javax.script.ScriptEngineFactory) will overwrite one another, resulting in faulty behavior. Tools: Maven Shade Plugin JAR of JARs. The final JAR file contains the other JAR files embedded within. Pro: Avoids dependency version clashes. All resource files are preserved. Con: Needs to bundle a special "bootstrap" classloader to enable Java to load classes from the wrapped JAR files. Debugging class loader issues becomes more complex. Tools: Eclipse JAR File Exporter, One-JAR.


Not quite true regarding services, shade plugin has transformers and one of them is for concatenating contents of files under the META-INF/services directory. More info here: maven.apache.org/plugins/maven-shade-plugin/examples/…
It basically encapsulates the artifact in its own namespace. I cannot think of any scenario where this still allows for clashes.
G
Glaucio Southier

My definitive solution on Eclipse Luna and m2eclipse: Custom Classloader (download and add to your project, 5 classes only) :http://git.eclipse.org/c/jdt/eclipse.jdt.ui.git/plain/org.eclipse.jdt.ui/jar%20in%20jar%20loader/org/eclipse/jdt/internal/jarinjarloader/; this classloader is very best of one-jar classloader and very fast;

<project.mainClass>org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader</project.mainClass> <project.realMainClass>my.Class</project.realMainClass>

Edit in JIJConstants "Rsrc-Class-Path" to "Class-Path" mvn clean dependency:copy-dependencies package is created a jar with dependencies in lib folder with a thin classloader

<build>
    <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.java</include>
                <include>**/*.properties</include>
            </includes>
        </resource>
        <resource>
            <directory>src/main/resources</directory>
            <filtering>true</filtering>
            <includes>
                <include>**/*</include>
            </includes>
            <targetPath>META-INF/</targetPath>
        </resource>
        <resource>
            <directory>${project.build.directory}/dependency/</directory>
            <includes>
                <include>*.jar</include>
            </includes>
            <targetPath>lib/</targetPath>
        </resource>
    </resources>
<pluginManagement>
        <plugins>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <mainClass>${project.mainClass}</mainClass>
                            <classpathPrefix>lib/</classpathPrefix>
                        </manifest>

                        <manifestEntries>
                            <Rsrc-Main-Class>${project.realMainClass}  </Rsrc-Main-Class>
                            <Class-Path>./</Class-Path>
                        </manifestEntries>

                    </archive>
                </configuration>
            </plugin>
<plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <executions>
                    <execution>
                        <id>copy-dependencies</id>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-dependencies</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </pluginManagement>
</build>

the maven-dependency-plugin dont work, always write on "dependency" folder
create a jar with a internal folder "dependency" containing project dependencies and put it on MANIFEST.MF
src/main/java **/*.java **/*.properties src/main/resources true **/* META-INF/ ${project.build.directory}/dependency/ *.jar lib/
Based on this answer I created this project. You shouldn't need to change anything except the pom file: github.com/raisercostin/jarinjarloader
m
mohdajami

Putting Maven aside, you can put JAR libraries inside the Main Jar but you will need to use your own classloader.

Check this project: One-JAR link text


There is also a Maven plugin for One-JAR: onejar-maven-plugin.googlecode.com/svn/mavensite/usage.html
k
krlzlx

Thanks I have added below snippet in POM.xml file and Mp problem resolved and create fat jar file that include all dependent jars.

<plugin>
    <artifactId>maven-assembly-plugin</artifactId>
        <executions>
            <execution>
                <phase>package</phase>
                <goals>
                    <goal>single</goal>
                </goals>
            </execution>
        </executions>
        <configuration>
            <descriptorRefs>
                <descriptorRef>dependencies</descriptorRef>
            </descriptorRefs>
        </configuration>
    </plugin>
</plugins>

j
jwpol

I was trying to do sth similar, but I didn't want all jars to be included. I wanted to include some specific directories from the given dependency. In addition classifier tag was already occupied, so I couldn't do:

<dependencies>
    <dependency>
        <groupId>your.group.id</groupId>
        <artifactId>your.artifact.id</artifactId>
        <version>1.0</version>
        <type>jar</type>
        <classifier>jar-with-dependencies</classifier>
    </dependency>
</dependencies>

I used maven-dependency-plugin and unpack goal And unpacked what I wanted to the ${project.build.directory}/classes, otherwise it will be omitted Because it was in the classes directory, maven finally placed it in the jar

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <executions>
        <execution>
            <id>unpack</id>
            <phase>prepare-package</phase>
            <goals>
                <goal>unpack</goal>
            </goals>
            <configuration>
                <artifactItems>
                    <artifactItem>
                        <groupId>my.group</groupId>
                        <artifactId>my.artifact</artifactId>
                        <classifier>occupied</classifier>
                        <version>1.0</version>
                        <type>jar</type>
                    </artifactItem>
                </artifactItems>
                <outputDirectory>${project.build.directory}/classes</outputDirectory>
                <includes>aaa/**, bbb/**, ccc/**</includes>
            </configuration>
        </execution>
    </executions>
</plugin>

F
Francois Gergaud

This post may be a bit old, but I also had the same problem recently. The first solution proposed by John Stauffer is a good one, but I had some problems as I am working this spring. The spring's dependency-jars I use have some property files and xml-schemas declaration which share the same paths and names. Although these jars come from the same versions, the jar-with-dependencies maven-goal was overwriting theses file with the last file found.

In the end, the application was not able to start as the spring jars could not find the correct properties files. In this case the solution propose by Rop have solved my problem.

Also since then, the spring-boot project now exist. It has a very cool way to manage this problem by providing a maven goal which overload the package goal and provide its own class loader. See spring-boots Reference Guide


C
Community

Have a look at this answer:

I am creating an installer that runs as a Java JAR file and it needs to unpack WAR and JAR files into appropriate places in the installation directory. The dependency plugin can be used in the package phase with the copy goal and it will download any file in the Maven repository (including WAR files) and write them where ever you need them. I changed the output directory to ${project.build.directory}/classes and then end result is that the normal JAR task includes my files just fine. I can then extract them and write them into the installation directory.

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
    <execution>
        <id>getWar</id>
        <phase>package</phase>
        <goals>
            <goal>copy</goal>
        </goals>
        <configuration>
            <artifactItems>
                <artifactItem>
                    <groupId>the.group.I.use</groupId>
                    <artifactId>MyServerServer</artifactId>
                    <version>${env.JAVA_SERVER_REL_VER}</version>
                    <type>war</type>
                    <destFileName>myWar.war</destFileName>
                </artifactItem>
            </artifactItems>
            <outputDirectory>${project.build.directory}/classes</outputDirectory>
        </configuration>
    </execution>
</executions>


N
NIrav Modi

To make it more simple, You can use the below plugin.

             <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                        <configuration>
                            <classifier>spring-boot</classifier>
                            <mainClass>
                                com.nirav.certificate.CertificateUtility
                            </mainClass>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

Please describe, how it exactly solves the problem
I have added only this plugin