Question

我正在尝试创建一个基于maven的项目，该项目有一个父pom，然后是两个模块。一个用于业务，一个用于依赖于业务的命令行应用程序。

父pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>dk.fitfit.triangle.parent</groupId>
    <artifactId>triangle-parent</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>Business</module>
        <module>Cmd</module>
    </modules>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <classpathPrefix>lib/</classpathPrefix>
                            <mainClass>dk.fitfit.triangle.cmd.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

然后我有业务pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>triangle-parent</artifactId>
        <groupId>dk.fitfit.triangle.parent</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <groupId>dk.fitfit.triangle.business</groupId>
    <artifactId>triangle-business</artifactId>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.7</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

最后是命令行应用程序的pom文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>triangle-parent</artifactId>
        <groupId>dk.fitfit.triangle.parent</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <groupId>dk.fitfit.triangle.cmd</groupId>
    <artifactId>triangle-cmd</artifactId>

    <dependencies>
        <dependency>
            <groupId>dk.fitfit.triangle.business</groupId>
            <artifactId>triangle-business</artifactId>
            <version>1.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

</project>

问题是当我尝试运行我的jar文件时，我收到以下错误消息

Exception in thread "main" java.lang.NoClassDefFoundError: dk/fitfit/triangle/business/Triangle
at dk.fitfit.triangle.cmd.Main.main(Main.java:17)
Caused by: java.lang.ClassNotFoundException: dk.fitfit.triangle.business.Triangle
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more

我正在尝试使用以下命令运行我的jar

mvn install && mvn package && java -jar Cmd/target/triangle-cmd-1.0-SNAPSHOT.jar 1 2 3

关于我做错了什么的线索？

Answer 1

在命令行应用程序的pom中，将maven-jar-plugin替换为以下内容。

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-assembly-plugin</artifactId>
        <version>2.4.1</version>
        <configuration>
                <descriptorRefs>
                      <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
                <archive>
                      <manifest>
                          <mainClass>dk.fitfit.triangle.cmd.Main</mainClass>
                      </manifest>
                </archive>
        </configuration>
        <executions>
            <execution>
                  <id>make-assembly</id>
                  <phase>package</phase>
                  <goals>
                      <goal>single</goal>
                  </goals>
           </execution>
         </executions>
</plugin>

现在你将得到一个包含所有可以使用的依赖项的胖jar。

Answer 2

每个模块都会生成一个单独的jar，也就是说，你有一个商业jar和一个cmd-jar。运行java命令时，只指定cmd-jar。

现在您有两个选择：

将busines-jar添加到类路径Set the classpath
将business-jar和cmd-jar捆绑到一个胖罐jar-with-dependencies

Maven和父项目

2 个答案: