Maven：如何使用随附的外部库执行可运行的jar（uberjar）

Question

Until now i made runnable jars with Ant and there were no problems with it.
However i now try to mavenize my project and i realy can't figured out how to do runable jar with this tool.
I've read tons of tutorials (also here, on Stackoverflow), helps, advices and... nothing. In my case all of them don't work which probably means i don't understand some basics.
I have such simple project:

This is app, witch use mysql-connector-java-5.1.24-bin.jar (placed in 'lib' dir) to connect to MySQL database.
I want to include this jar into final jar (DBPreformatter.jar). I used assembly and shaded plugins in many configurations, but they NEVER added this jar into DBPreformatter.jar.

This is my pom.xml:

<modelVersion>4.0.0</modelVersion>
<groupId>com.icd4you</groupId>
<artifactId>DBPreformatter</artifactId>
<version>1.0.0</version>
<name>DBPreformatter</name>
<description>DB processing and cleaning tool</description>
<packaging>jar</packaging>
<dependencies>
    <dependency>
        <groupId>mysql-connector-java-5.1.24-bin</groupId>
        <artifactId>mysql-connector-java-5.1.24-bin</artifactId>
        <version>5.1.24</version>
        <scope>system</scope>
        <systemPath>${basedir}/lib/mysql-connector-java-5.1.24-bin.jar</systemPath>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
            </configuration>
        </plugin>

        <!-- WHAT SHOULD I USE HERE? -->

    </plugins>
</build>

How to solve this problem?

Answer 1

有一个Maven插件Apache Maven Shade Plugin ，它将为您构建一个uber jar。

Answer 2

Add the Maven Assembly plugin with the descriptor jar-with-dependencies :

<build>
    <plugins>
        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <configuration>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
                <archive>
                    <manifest>
                        <mainClass>com.pany.your.MainClass</mainClass>
                    </manifest>
                </archive>
            </configuration>
            <executions>
                <execution>
                    <id>make-assembly</id>
                    <phase>package</phase>
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

Note that this doesn't add the JAR; instead it unpacks all JARs which are listed as dependencies and adds their content to the resulting JAR (so you'll see all the class files from the MySQL JAR in the result instead of the MySQL JAR itself).

EDIT There is a caveat, though: Maven ignores JARs with scope=system for many operations. See also: How to include external jars in maven jar build process?

If Maven doesn't add the JAR to the output, then you must install all JARs with this scope into your local maven repo ( $HOME/.m2/repository ) using the mvn install:file-install command. See http://maven.apache.org/plugins/maven-install-plugin/usage.html how to do that.

Note: Installing libraries in your local repo is the preferred way; you should really consider it. For one, the scope=system will no longer confuse you (since many plugins handle them in a special way). Plus you need to do this only once. Afterwards, you can use this library in many Maven projects.

Before installing, you should check http://search.maven.org/ to see if the dependency isn't already known to Maven.

MySQL is: http://search.maven.org/#artifactdetails%7Cmysql%7Cmysql-connector-java%7C5.1.32%7Cjar