java.lang.ClassNotFoundException : org. springframework.boot.SpringApplication 与 maven-jar-plugin

Question

我是 Spring 和 Maven 的新手。我正在尝试运行一个简单应用程序的 jar，但收到以下错误:

java -jar target/gs-rest-service-0.0.1-SNAPSHOT.jar 
Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
    at hello.Application.main(Application.java:10)
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
    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

这是 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>gs-rest-service</groupId>
  <artifactId>gs-rest-service</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>MyApp</name>
  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>hello.Application</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
    </plugins>
  </build>
  <dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>4.3.10.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot</artifactId>
        <version>1.5.5.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-autoconfigure</artifactId>
        <version>1.5.5.RELEASE</version>
    </dependency>
  </dependencies>
</project>

这是需要 SpringApplication 的主类:

package hello;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

我还可以看到 org.springframework.boot.SpringApplication 位于 Maven Dependencies 库中应有的位置。所以我不太确定是什么导致了这个错误。

有什么想法吗？

Answer 1

可以尝试将maven-jar-plugin版本升级到3.0.2和

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>3.0.2</version>
        <configuration>
          <archive>
            <manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
          </archive>
        </configuration>
        ...
      </plugin>
    </plugins>
  </build>
  ...
</project>

如果仍然出现此错误，那么您可以关注 this stackoverflow 链接，soemirno 提出的问题，您可以从中获得专家对此问题的合适答案。