通过appassembler-maven-plugin生成的脚本无法在Spring Boot应用程序中找到主类 [英] Script generated via appassembler-maven-plugin is not able to find main class in Spring Boot application
问题描述
我使用appassembler-maven-plugin生成的启动脚本有问题。
我有一个只有一个类的基本spring-boot应用程序:
I have a problem with the start script that I generate with appassembler-maven-plugin. I have a basic spring-boot application with only one class:
@SpringBootApplication
public class ScriptDemoApplication {
public static void main(String[] args) {
SpringApplication.run(ScriptDemoApplication.class, args);
}
}
和我的pom.xml
and my 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>org.home.sziolkow</groupId>
<artifactId>script-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>script-demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.7</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<mainClass>${start-class}</mainClass>
</configuration>
<executions>
<execution>
<goals>
<goal>
repackage
</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>appassembler-maven-plugin</artifactId>
<version>1.10</version>
<configuration>
<goal>
package
</goal>
<showConsoleWindow>
true
</showConsoleWindow>
<platforms>
<platform>unix</platform>
</platforms>
<programs>
<program>
<mainClass>org.home.sziolkow.ScriptDemoApplication</mainClass>
<id>app</id>
</program>
</programs>
</configuration>
</plugin>
</plugins>
</build>
</project>
我运行maven: mvn package appassembler:assemble
生成包和脚本但是当我尝试运行 ./ target / appassembler / bin / app
,我得到
Package and scripts are generated but when I try to run ./target/appassembler/bin/app
, I get
错误:无法找到或加载主类org.home.sziolkow.ScriptDemoApplication
Error: Could not find or load main class org.home.sziolkow.ScriptDemoApplication
我测试了生成的包,我可以毫无问题地启动应用程序:
I tested generated packages and I can start the application without problems with:
java -jar ./target/appassembler/repo/org/home/sziolkow/script-demo/0.0.1-SNAPSHOT/script-demo-0.0.1-SNAPSHOT.jar
推荐答案
由于Spring Boot重新打包JAR的方式,你遇到了麻烦它是一个可执行的JAR。来自文档:
You're having this trouble because of the way Spring Boot is repackaging your JAR, in order to make it an executable JAR. From the documentation:
可执行存档不能用作依赖项,因为可执行的jar格式包
BOOT-INF / classes
中的应用程序类。这意味着当可执行jar用作依赖项时无法找到它们。
The executable archive cannot be used as a dependency as the exectuable jar format packages application classes in
BOOT-INF/classes
. This means that they cannot be found when the executable jar is used as a dependency.
基本上,Spring Boot Maven插件重新打包你的JAR并将您的类放入 BOOT-INF / classes
, BOOT-INF / lib
中的所有JAR依赖项,并启动其 JarLauncher
类作为主类,它将在这些位置搜索类和JAR。
Essentially, the Spring Boot Maven Plugin repackages your JAR and puts your classes inside BOOT-INF/classes
, all the JAR dependencies inside BOOT-INF/lib
, and launches its JarLauncher
class as main class, which will search for classes and JARs at those locations.
所以你有2解决方案:不要使用Spring Boot将JAR重新打包成可执行的JAR,或者根本不使用Appassembler插件。
So you have 2 solutions: do not use Spring Boot to repackage your JAR into an executable JAR, or do not use the Appassembler plugin at all.
由于Spring Boot为您创建了一个可执行的JAR,因此不需要使用Appassembler插件生成脚本。删除 appassembler-maven-plugin
的插件声明,并拥有:
Since Spring Boot creates an executable JAR for you, generating scripts with the Appassembler plugin is not necessary. Remove the plugin declaration for appassembler-maven-plugin
and have:
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<mainClass>org.home.sziolkow.ScriptDemoApplication</mainClass>
</configuration>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
POM的唯一变化是添加< mainClass>
指向主类的参数,以及 appassembler-maven-plugin
的删除。启动 mvn clean package
时,您将能够直接启动生成的可执行JAR:
The only change with your POM is the addition of the <mainClass>
parameter pointing to your main class, and the removal of the appassembler-maven-plugin
. When launching mvn clean package
, you'll be able to launch the generated executable JAR directly with:
java -jar target/script-demo-0.0.1-SNAPSHOT.jar
如果可执行文件名称中的版本0.0.1-SNAPSHOT存在问题,您只需设置< finalName>
即可你的POM:
If the version 0.0.1-SNAPSHOT in the name of the executable is an issue, you can simply set a <finalName>
in your POM:
<build>
<finalName>${project.artifactId}</finalName>
<!-- ... -->
</build>
然后使用 java -jar target / script启动可执行JAR -demo.jar
。
如前所述,自从Spring Boot repackage
目标将类和JAR放在 BOOT-INF
文件夹中,我们需要摆脱它。所以删除 spring-boot-maven-plugin
插件声明,并进入你的POM:
As said before, since Spring Boot repackage
goal put the classes and JARs inside a BOOT-INF
folder, we need to get rid of that. So remove the spring-boot-maven-plugin
plugin declaration, and have in your POM:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>appassembler-maven-plugin</artifactId>
<version>1.10</version>
<executions>
<execution>
<id>assemble</id>
<goals>
<goal>assemble</goal>
</goals>
<phase>package</phase>
<configuration>
<showConsoleWindow>true</showConsoleWindow>
<platforms>
<platform>unix</platform>
</platforms>
<programs>
<program>
<mainClass>org.home.sziolkow.ScriptDemoApplication</mainClass>
<id>app</id>
</program>
</programs>
</configuration>
</execution>
</executions>
</plugin>
与当前POM的区别在于Appassembler绑定到包
阶段,以便在不调用 appassembler:assemble
的情况下启动执行。然后,当运行 mvn clean package
时,您将能够使用Appassembler生成的脚本启动您的应用程序:
The difference with your current POM is that the Appassembler is bound to the package
phase, so that the execution is launched without invoking appassembler:assemble
. Then, when running mvn clean package
, you'll be able to start your application using the scripts generated by the Appassembler:
./target/appassembler/bin/app
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