java.lang.NoClassDefFoundError: org/springframework/context/ApplicationContext maven [英] java.lang.NoClassDefFoundError: org/springframework/context/ApplicationContext maven
问题描述
我是 spring 和 maven 的新手.我有一个使用 Spring 的简单 hello world 项目.项目构建成功,但我在运行时遇到以下错误:
I am new to spring and maven. I have a simple hello world project using Spring . The project builds successfully but i face the following error at runtime:
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/context/ApplicationContext
这是主应用程序:App.java
This is the main app: App.java
package com.test.SpringMaven2;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args )
{
System.out.println( "Hello World!" );
System.out.println( "Hello World!" );
ApplicationContext context = new AnnotationConfigApplicationContext(HelloWorldConfig.class);
HelloWorld hello = (HelloWorld) context.getBean("helloWorld");
hello.setName("Adnan");
hello.getName();
}
}
这是HelloWorld bean
This is the HelloWorld bean
package com.test.SpringMaven2;
public class HelloWorld{
private String name;
public void setName(String name){
this.name = name;
}
public void getName(){
System.out.println("Hello, " + name);
}
}
这是基于注解的配置文件:
This is the annotation based configuration file:
package com.test.SpringMaven2;
import org.springframework.context.annotation.*;
@Configuration
public class HelloWorldConfig{
@Bean
public HelloWorld helloWorld(){
return new HelloWorld();
}
}
这是我的 pom.xml
This is my pom.xml
<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.test</groupId>
<artifactId>SpringMaven2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>SpringMaven2</name>
<url>http://maven.apache.org</url>
<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>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>4.3.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.3.3.RELEASE</version>
</dependency>
</dependencies>
</project>
我在 CMD 中运行以下命令来运行应用程序:java -cp {nameofresultjarfile} com.test.SpringMaven2.App
I am running the following command in CMD to run the application: java -cp {nameofresultjarfile} com.test.SpringMaven2.App
但是得到上面的错误信息
But getting the error messsage above
有什么建议吗?
谢谢
推荐答案
您的 pom.xml
创建一个 jar 文件,其中仅包含您的项目中定义的类.但不包括您的应用程序所需的所有其他依赖项(spring-core、spring-context-support).
Your pom.xml
creates a jar file which contains only the classes defined in your project. But all the other dependencies (spring-core, spring-context-support) which are required by your application aren't included.
如果您的应用程序是在 eclipse 中启动的,eclipse 会将这些所需的 jar 文件集成到应用程序的类路径中,以便它能够运行.
如果您的应用程序是从 CMD 启动的,则在类路径中找不到 spring 类,并且您会收到 java.lang.NoClassDefFoundError
.
If your application is started within eclipse, eclipse integrates these required jar files to the classpath of the application and so it is able to run.
If your application is started from CMD the spring classes can't be found in the classpath and you get a java.lang.NoClassDefFoundError
.
当应用程序从 CMD(类路径)启动时,可以手动命名所有需要的 jar,但是创建一个所谓的自包含 jar 文件要容易得多,其中已经包含了所有这些.这可以使用 maven-assembly-plugin 来完成.
It's possible to name all the required jars manually when the application is started from CMD (classpath), but is much easier to created a so called self contained jar file, which has all of them already included. This can be done using maven-assembly-plugin.
可以找到如何创建自包含 jar 文件的示例 这里.
An example how to create a self contained jar file can be found here.
现在可以从 CMD 启动自包含 jar 中的应用程序:
java -jar name_of_your_project-jar-with-dependencies.jar
The application in a self contained jar can be started now from CMD:
java -jar name_of_your_project-jar-with-dependencies.jar
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