SBT+spring-boot：“在 META-INF/spring.factories 中找不到自动配置类”

Question

我有一个用 Scala 编写的 Spring Boot 应用程序。我正在使用 SBT 来构建项目。我已经使用“sbt-assembly”生成了一个大的胖 jar，并将所有必需的依赖项添加为一个。

sbt.version = 1.3.5 scalaVersion := "2.13.1"

下面是我的 build.sbt 文件

import BuildUtils.readVersion

name := "DiscoveryEngine"
version := "0.1"
scalaVersion := "2.13.1"
organization := "com.javasree.scala.discoveryengine"
publishMavenStyle := true

lazy val artifactoryRepo = settingKey[sbt.librarymanagement.Resolver]("Artifactory repository value")

isSnapshot := {
  sys.props.getOrElse("DISCOVERY_ENGINE_SNAPSHOT", sys.env.getOrElse("DISCOVERY_ENGINE_SNAPSHOT", "true")) match {
    case "true" | "1" => true
    case "false" | "0" => false
    case _ => println("taking the default value as true for 'SNAPSHOT'")
      true
  }
}

publishArtifact in (Compile, packageDoc) := false
publishArtifact in (Compile, packageSrc) := false

/*
if env variable(DISCOVERY_ENGINE_SNAPSHOT) is set to true then build will do "snapshot"
or else it will be "release"
* */
version := {
  readVersion("app-build")+
    (isSnapshot.value match {
      case true => "-SNAPSHOT"
      case false => ""
    })
}

artifactoryRepo := {
  val repoURL = "http://localhost:8081/artifactory"
  (isSnapshot.value match {
    case true => "jfrog-snapshot" at s"${repoURL}/javasree-sbt-snapshot;build.timestamp=" + new java.util.Date().getTime
    case false => "jfrog-remote" at s"${repoURL}/javasree-sbt-local"
  })
}

publishTo := Some( artifactoryRepo.value )
credentials += Credentials("Artifactory Realm", "localhost", "admin", "password")

assemblyMergeStrategy in assembly := {
  case PathList("META-INF", xs @ _*) => MergeStrategy.discard
  case x => MergeStrategy.last
}

  libraryDependencies ++= Seq(
    "com.google.code.gson" % "gson" % "2.8.2" % "provided"
  )++Dependencies.springDependencies

我是 scala 和 sbt 的新手。由于谷歌搜索，一些东西是盲目添加的。只是为了确保我的构建工作。一种这样的代码是程序集合并策略。

当我遇到“重复数据删除发现错误”时，我使用了不同的 mergeStrategy 代码。经过几次跟踪和错误方法后，我终于能够生成胖罐子了。最初我的胖罐子没有成功运行，因为它再次失败并出现不同的错误“无法加载主......”。 上面的构建脚本是我生成胖 jar 的最终脚本，我能够运行 jar。这次它没有给出“无法加载主...”错误，而是给了我新的不同错误，如下所示。

$ java -jar DiscoveryEngine-assembly-1.0-SNAPSHOT.jar
00:44:54.232 [main] DEBUG org.springframework.web.context.support.StandardServletEnvironment - Activating profiles []

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::         (v1.0-SNAPSHOT)

00:44:54.323 [main] INFO scala.App - Starting App v1.0-SNAPSHOT on LAPTOP-U3JTGOFA with PID 5648 (H:\Projects\Scala\DiscoryEngine\target\scala-2.13\DiscoveryEngine-assembly-1.0-SNAPSHOT.jar started by sree in H:\Projects\Scala\DiscoryEngine\target\scala-2.13)
00:44:54.324 [main] DEBUG scala.App - Running with Spring Boot v1.0-SNAPSHOT, Spring v1.0-SNAPSHOT
00:44:54.324 [main] INFO scala.App - No active profile set, falling back to default profiles: default
00:44:54.325 [main] DEBUG org.springframework.boot.SpringApplication - Loading source class com.javasree.scala.discoveryengine.DiscoveryEngine
00:44:54.367 [main] DEBUG org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext - Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@1445d7f
00:44:54.378 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'org.springframework.context.annotation.internalConfigurationAnnotationProcessor'
00:44:54.477 [main] ERROR org.springframework.boot.SpringApplication - Application run failed
java.lang.IllegalArgumentException: No auto configuration classes found in META-INF/spring.factories. If you are using a custom packaging, make sure that file is correct.
    at org.springframework.util.Assert.notEmpty(Assert.java:464)
    at org.springframework.boot.autoconfigure.AutoConfigurationImportSelector.getCandidateConfigurations(AutoConfigurationImportSelector.java:173)
    at org.springframework.boot.autoconfigure.AutoConfigurationImportSelector.getAutoConfigurationEntry(AutoConfigurationImportSelector.java:116)
    at org.springframework.boot.autoconfigure.AutoConfigurationImportSelector$AutoConfigurationGroup.process(AutoConfigurationImportSelector.java:396)
    at org.springframework.context.annotation.ConfigurationClassParser$DeferredImportSelectorGrouping.getImports(ConfigurationClassParser.java:875)
    at org.springframework.context.annotation.ConfigurationClassParser$DeferredImportSelectorGroupingHandler.processGroupImports(ConfigurationClassParser.java:801)
    at org.springframework.context.annotation.ConfigurationClassParser$DeferredImportSelectorHandler.process(ConfigurationClassParser.java:771)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:185)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:315)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:232)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:95)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:705)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:531)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:743)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:390)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:312)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1214)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1203)
    at com.javasree.scala.discoveryengine.DiscoveryEngine$.delayedEndpoint$com$javasree$scala$discoveryengine$DiscoveryEngine$1(DiscoveryEngine.scala:13)
    at com.javasree.scala.discoveryengine.DiscoveryEngine$delayedInit$body.apply(DiscoveryEngine.scala:12)
    at scala.Function0.apply$mcV$sp(Function0.scala:39)
    at scala.Function0.apply$mcV$sp$(Function0.scala:39)
    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:17)
    at scala.App.$anonfun$main$1(App.scala:73)
    at scala.App.$anonfun$main$1$adapted(App.scala:73)
    at scala.collection.IterableOnceOps.foreach(IterableOnce.scala:553)
    at scala.collection.IterableOnceOps.foreach$(IterableOnce.scala:551)
    at scala.collection.AbstractIterable.foreach(Iterable.scala:921)
    at scala.App.main(App.scala:73)
    at scala.App.main$(App.scala:71)
    at com.javasree.scala.discoveryengine.DiscoveryEngine$.main(DiscoveryEngine.scala:12)
    at com.javasree.scala.discoveryengine.DiscoveryEngine.main(DiscoveryEngine.scala)
00:44:54.479 [main] DEBUG org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext - Closing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@1445d7f, started on Tue May 05 00:44:54 IST 2020

我确信这与我的 sbt-assembly 插件和我的 MergeStrategy 有关，但 SO 的另一个线程中的解决方案没有解决我的问题，除了询问 SO 专家之外，我别无选择并交叉我的手指以获得正确的答案。先感谢您。

Answer 1

Merge 策略都没有正确合并 spring.factories 文件。

所以我做到了

我用 scala 创建了汇编 jar，没有库依赖

Sbt assembly

然后我使用 sbt package native plugin 来获取 my_lib 文件夹中的所有依赖 jar

Sbt univarsal:packageBin

我通过命令运行 jar

Java -classpath "my_lib/*;my jar" my.main