java - AWS EC2 Java Spring Boot - 线程 "main"java.lang.NoClassDefFoundError : org/springframework/boot/SpringApplication 中出现异常

Question

您好，我正在尝试在 AWS EC2 实例中运行 Spring Boot，但收到以下错误:

EC2 中的命令:java -jar app-dal-1.0-SNAPSHOT.jar

Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
        at com.smartcommunity.smartparking.appdal.BootApp.main(BootApp.java:12)
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
        at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        ... 1 more

在我的本地计算机上一切正常。

本地 Java 版本“9.0.4”- EC2 Java 版本 1.8.0

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>com.smartcommunity.smartparking</groupId>
    <artifactId>app-dal</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>



    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.0.4.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.3</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.8</version>
        </dependency>

            <dependency>
                <groupId>org.mongodb</groupId>
                <artifactId>mongodb-driver</artifactId>
                <version>3.5.0</version>
            </dependency>

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.3.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.3.1</version>
        </dependency>


        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-core</artifactId>
            <version>8.5.32</version>
        </dependency>
    </dependencies>

    <build>
        <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}/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.smartcommunity.smartparking.appdal.BootApp</mainClass>
                        </manifest>
                    </archive>


                </configuration>

            </plugin>
        </plugins>
    </build>

</project>

我使用 IntelliJ Maven Lifecycle 遵循的步骤:

• Maven 清洁
• Maven 编译
• Maven 包
• Maven 安装

Answer 1

当使用 Spring Boot 时，它需要您的 jar 文件中有一个特殊的结构。 spring-boot-maven-plugin 确保在 jar 中创建此结构。

spring-boot-maven-plugin专门设计和构建为基于 Spring Boot 的应用程序创建可执行 jar 文件。因此，而不是您明确添加的 >maven-dependency-plugin和maven-jar-plugin ，将其替换为单个 spring-boot-maven-plugin 。

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        <plugin>
    </plugins>
</build>

基本上这就是您所需要的。