如何使用 Maven 将所有必需的 JAR 文件放在最终 JAR 文件内的库文件夹中? [英] How do I put all required JAR files in a library folder inside the final JAR file with Maven?

问题描述

我在我的独立应用程序中使用 Maven，并且我想将 JAR 文件中的所有依赖项打包到一个库文件夹中，如以下答案之一所述:

I am using Maven in my standalone application, and I want to package all the dependencies in my JAR file inside a library folder, as mentioned in one of the answers here:

我如何创建使用 Maven 的具有依赖项的可执行 JAR?

我希望我的最终 JAR 文件有一个包含依赖项作为 JAR 文件的库文件夹，而不是像 Maven 那样以文件夹形式放置依赖项的 maven-shade-plugin.m2 文件夹中的层次结构.

I want my final JAR file to have a library folder that contains the dependencies as JAR files, not like what the maven-shade-plugin that puts the dependencies in the form of folders like the Maven hierarchy in the .m2 folder.

嗯，实际上当前的配置做了我想要的，但是我在运行应用程序时加载 JAR 文件有问题.我无法加载课程.

Well, actually the current configuration does what I want, but I am having a problem with loading the JAR files when running the application. I can't load the classes.

这是我的配置:

<plugins>

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <executions>
            <execution>
                <id>copy-dependencies</id>
                <phase>prepare-package</phase>
                <goals>
                    <goal>copy-dependencies</goal>
                </goals>
                <configuration>
                    <outputDirectory>${project.build.directory}/classes/lib</outputDirectory>
                    <overWriteReleases>false</overWriteReleases>
                    <overWriteSnapshots>false</overWriteSnapshots>
                    <overWriteIfNewer>true</overWriteIfNewer>
                </configuration>
            </execution>
        </executions>
    </plugin>

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <configuration>
            <archive>
                <manifest>
                    <addClasspath>true</addClasspath>
                    <classpathPrefix>lib/</classpathPrefix>
                    <mainClass>com.myapp.MainClass</mainClass>
                </manifest>
            </archive>
        </configuration>
    </plugin>

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
            <source>1.6</source>
            <target>1.6</target>
        </configuration>
    </plugin>

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <executions>
            <execution>
                <id>install</id>
                <phase>install</phase>
                <goals>
                    <goal>sources</goal>
                </goals>
            </execution>
        </executions>
    </plugin>

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-resources-plugin</artifactId>
        <version>2.5</version>
        <configuration>
            <encoding>UTF-8</encoding>
        </configuration>
    </plugin>

</plugins>

该项目在 Eclipse 中运行良好，并且 JAR 文件按照我的需要放在我最终 JAR 文件中的库文件夹中，但是当从目标文件夹运行最终 JAR 文件时，我总是得到 ClassNotFoundException:

The project runs fine from Eclipse, and the JAR files are put in the library folder inside my final JAR file as I want, but when running the final JAR file from the target folder I always get ClassNotFoundException:

Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/context/ApplicationContext
Caused by: java.lang.ClassNotFoundException: org.springframework.context.ApplicationContext
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: com.myapp.MainClass. Program will exit.

如何修复此异常?

推荐答案

点击此链接:

如何:Eclipse Maven 安装带有依赖项的构建 jar

我发现这不是可行的解决方案，因为类加载器不会从 jar 内加载 jar，所以我想我会解压 jar 内的依赖项.

i found out that this is not workable solution because the class loader doesn't load jars from within jars, so i think that i will unpack the dependencies inside the jar.

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