Maven java 项目构建，但不运行 [英] Maven java project builds, but doesn't run

问题描述

我正在从头开始创建一个maven项目，首先只是学习如何使用maven.主项目不包含源代码文件，但它有两个模块(app 和 util).应用程序依赖于 util.我想要一个来自应用程序的 .jar，如果可能的话，没有清单文件.我可以使用 mvn clean install 编译整个项目，但无法从控制台运行该应用程序.

I am creating a maven project from scratch, first just learn how to use maven. The main project contains no source code file, but it has two modules (app, and util). App depends on util. I would like to have a .jar from app, and have no manifest file if possible. I am able to compile the whole project with mvn clean install, but can not run the app from console.

主要项目 .pom 是

<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>com.proba</groupId>
  <artifactId>myproject</artifactId>
  <version>0.0.1</version>
<packaging>pom</packaging>


<modules>
  <module>util</module>
  <module>app</module>
</modules>
</project>

Util .pom 是

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

  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>com.proba</groupId>
    <artifactId>myproject</artifactId>
    <version>0.0.1</version>
  </parent>
  <artifactId>util</artifactId>


 <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
     </dependency>
 </dependencies>

</project>

app pom 是

<?xml version="1.0"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.proba</groupId>
        <artifactId>myproject</artifactId>
        <version>0.0.1</version>
    </parent>
    <artifactId>app</artifactId>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.proba</groupId>
            <artifactId>util</artifactId>
            <version>0.0.1</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>com.proba.app.App</mainClass>
                            <addClasspath>true</addClasspath>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.1.1</version>
                <executions>
                    <execution>
                        <phase>site-deploy</phase>
                        <goals>
                            <goal>java</goal>
                        </goals>
                        <configuration>
                            <mainClass>com.proba.app.App</mainClass>
                            <!--<arguments> <argument>myArg1</argument> <argument>myArg2</argument> 
                                </arguments> -->
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

代码没有做太多事情.App.java(在 app 模块内)是包 com.proba.app;

The code doesn't do too much. App.java (that inside the app module) is package com.proba.app;

import com.proba.util.UtilClass;
public class App 
{
    public static void main( String[] args )
    {
        System.out.println( "Hello World!" );
        UtilClass uc = new UtilClass(); 
        System.out.println( "QQQQQ: " + uc.print() );
    }
}

我编译它

mvn clean install
[INFO] Reactor Summary:
[INFO]
[INFO] myproject .......................................... SUCCESS [  0.406 s]
[INFO] util ............................................... SUCCESS [  2.074 s]
[INFO] app ................................................ SUCCESS [  0.535 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

myproject、util、app 成功了.

myproject, util, app is SUCCESS.

我尝试运行它

java -jar app/target/app-0.0.1.jar
Hello World!
Exception in thread "main" java.lang.NoClassDefFoundError: com/proba/util/UtilClass
        at com.proba.app.App.main(App.java:17)
Caused by: java.lang.ClassNotFoundException: com.proba.util.UtilClass
        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

如您所见，Hello World！打印出来了，但是没有找到UtilClass.我可以从 Eclipse 运行构建，但不能从控制台运行.我做错了什么?你有什么想法吗?

As you can see, Hello World! is printed out, but UtilClass is not found. I am able to run the build from eclipse, but not from the console. What I am doing wrong? Do you have any idea?

推荐答案

你缺少的是 UtilClass 的 jar.你只需要在你的 pom.xml 中添加 shade 插件.作为参考:maven-shade-plugin

What you missing is the jar of UtilClass. You just need to add shade plugin in your pom. As reference: maven-shade-plugin

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