Maven多模块项目在IntelliJ中工作,但通过命令行运行;java.lang.NoClassDefFoundError“;
我开始用Maven inside IntelliJ编写一个基本的Hello World多模块项目。它可以通过内置的run按钮完美地运行,但是当我使用Maven多模块项目在IntelliJ中工作,但通过命令行运行;java.lang.NoClassDefFoundError“;,java,maven,intellij-idea,Java,Maven,Intellij Idea,我开始用Maven inside IntelliJ编写一个基本的Hello World多模块项目。它可以通过内置的run按钮完美地运行,但是当我使用mvn install通过命令行构建项目,然后尝试使用java-cp HelloWorld/target/HelloWorld-1.0-SNAPSHOT.jar App运行它时,它说 线程“main”java.lang.NoClassDefFoundError中出现异常: App.main(App.java:5)处的MoreDataClass由以下原
mvn install
通过命令行构建项目,然后尝试使用java-cp HelloWorld/target/HelloWorld-1.0-SNAPSHOT.jar App
运行它时,它说
线程“main”java.lang.NoClassDefFoundError中出现异常:
App.main(App.java:5)处的MoreDataClass由以下原因引起:
java.lang.ClassNotFoundException:MoreDataClass位于
java.net.URLClassLoader.findClass(URLClassLoader.java:381)位于
loadClass(ClassLoader.java:424)位于
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)位于
loadClass(ClassLoader.java:357)
可能问题在于项目结构(IntelliJ提供给我的):
HelloWorld
-模块中的App.java
如下所示:
public class App {
public static void main(String[] args) {
System.out.println("Hello World");
MoreDataClass c = new MoreDataClass();
System.out.println(c.getMoreData());
}
}
而GetMoreData
-模块内部的MoreDataClass
包含以下代码:
public class MoreDataClass {
public String getMoreData() {
return "Here is some more data from the Module GetMoreData";
}
}
在IntelliJ中运行App.main()
,将在标准输出处返回(假设)以下行:
Hello World
Here is some more data from the Module GetMoreData
另一方面,在命令行中通过Maven运行它(如开头所述),将返回以下结果:
Hello World
Exception in thread "main" java.lang.NoClassDefFoundError: MoreDataClass
at App.main(App.java:5)
Caused by: java.lang.ClassNotFoundException: MoreDataClass
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more
因此,App.main()
已经构建并可以执行,但它找不到MoreDataClass
。为什么不呢
如果这些都与问题有关,下面是我的pom.xml:
****** parent/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>de.playground.multiModule</groupId>
<artifactId>parent</artifactId>
<packaging>pom</packaging>
<version>1.0-SNAPSHOT</version>
<modules>
<module>GetMoreData</module>
<module>HelloWord</module>
</modules>
</project>
***** parent/GetMoreData/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">
<parent>
<artifactId>parent</artifactId>
<groupId>de.playground.multiModule</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>GetMoreData</artifactId>
</project>
***** parent/HelloWorld/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">
<parent>
<artifactId>parent</artifactId>
<groupId>de.playground.multiModule</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>HelloWord</artifactId>
<dependencies>
<dependency>
<groupId>de.playground.multiModule</groupId>
<artifactId>GetMoreData</artifactId>
<version>1.0-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
</dependencies>
</project>
*****parent/pom.xml:******
4.0.0
操场
父母亲
聚甲醛
1.0-快照
GetMoreData
赫洛沃德
*****父级/GetMoreData/pom.xml*****
父母亲
操场
1.0-快照
4.0.0
GetMoreData
*****parent/HelloWorld/pom.xml*****
父母亲
操场
1.0-快照
4.0.0
赫洛沃德
操场
GetMoreData
1.0-快照
编译
您需要将GetMoreData
jar添加到类路径,或者配置HelloWorld
s构建以生成
****** parent/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>de.playground.multiModule</groupId>
<artifactId>parent</artifactId>
<packaging>pom</packaging>
<version>1.0-SNAPSHOT</version>
<modules>
<module>GetMoreData</module>
<module>HelloWord</module>
</modules>
</project>
***** parent/GetMoreData/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">
<parent>
<artifactId>parent</artifactId>
<groupId>de.playground.multiModule</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>GetMoreData</artifactId>
</project>
***** parent/HelloWorld/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">
<parent>
<artifactId>parent</artifactId>
<groupId>de.playground.multiModule</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>HelloWord</artifactId>
<dependencies>
<dependency>
<groupId>de.playground.multiModule</groupId>
<artifactId>GetMoreData</artifactId>
<version>1.0-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
</dependencies>
</project>