springboot服務引入外部jar包在windows運行正常，在linux環境上無法加載到引入jar包的類

一、問題描述

　　最近開發了一個springboot程序，需要依賴第三方jar包，這個jar包無法直接通過pom遠程倉庫下載，需要從自己本地引入，於是配置pom文件如下：將本地jar包引入工程，systemPath為jar所在的本地路徑

<!--第三方jar包引入-->
<dependency>
　　<groupId>com.hikvision.js</groupId>
　　<artifactId>data-sdk-bms</artifactId>
　　<version>2.0.3</version>
　　<scope>system</scope>
　　<systemPath>${project.basedir}/lib/data-sdk-bms-2.0.3.jar</systemPath>
</dependency>

在打包時將本地引入的jar引入打進lib文件夾下，如果沒有如下配置，jar無法打入lib目錄

<dependencySets>  
        <dependencySet>
            <useProjectArtifact>false</useProjectArtifact>
            <outputDirectory>lib</outputDirectory>
            <unpack>false</unpack>
            <scope>system</scope>
        </dependencySet>
</dependencySets>

然后使用maven打包，首先部署到windows機器上，啟動程序，運行正常，然后將程序部署到linux環境上，運行報如下錯誤：

[WARN ] [2020-09-09 09:28:15] [org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550)] Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanDefinitionStoreException: Failed to parse configuration class [com.hikvision.js.deployalarmtool.DeployalarmtoolApplication]; nested exception is java.io.FileNotFoundException: class path resource [com/hikvision/bms/caller/BmsMessage.class] cannot be opened because it does not exist
[ERROR] [2020-09-09 09:28:15] [org.springframework.boot.SpringApplication.reportFailure(SpringApplication.java:771)] Application startup failed
org.springframework.beans.factory.BeanDefinitionStoreException: Failed to parse configuration class [com.hikvision.js.deployalarmtool.DeployalarmtoolApplication]; nested exception is java.io.FileNotFoundException: class path resource [com/hikvision/bms/caller/BmsMessage.class] cannot be opened because it does not exist
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:183)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:308)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:228)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:272)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:92)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:687)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:524)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:124)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107)
    at com.hikvision.js.deployalarmtool.DeployalarmtoolApplication.main(DeployalarmtoolApplication.java:14)
Caused by: java.io.FileNotFoundException: class path resource [com/hikvision/bms/caller/BmsMessage.class] cannot be opened because it does not exist
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:172)
    at org.springframework.core.type.classreading.SimpleMetadataReader.<init>(SimpleMetadataReader.java:50)
    at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:102)
    at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.createMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:89)
    at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.getMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:76)
    at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:80)
    at org.springframework.context.annotation.ConfigurationClassParser.asSourceClass(ConfigurationClassParser.java:701)
    at org.springframework.context.annotation.ConfigurationClassParser$SourceClass.getInterfaces(ConfigurationClassParser.java:879)
    at org.springframework.context.annotation.ConfigurationClassParser.processInterfaces(ConfigurationClassParser.java:368)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:325)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:247)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:192)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:297)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:247)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:200)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:169)
    ... 13 more

nested exception is java.io.FileNotFoundException: class path resource [com/hikvision/bms/caller/BmsMessage.class] cannot be opened because it does not exist，顯然是com/hikvision/bms/caller/BmsMessage.class這個類不存在，而這個類正是引入的本地的那個jar包中的，檢查lib目錄發現jar是存在的，並且權限也正常，這就很奇怪，一時間束手無策。

排查無果，又重新打包，發現一個maven的warning日志：

[WARNING] 'dependencies.dependency.systemPath' for com.hikvision.js:data-sdk-bms:jar should not point at files within the project directory, ${project.basedir}/lib/data-sdk-bms-2.0.3.jar will be unresolvable by dependent projects @ line 113, column 25

於是我便從這個warning入手進行排查，果然warning解決，問題也得到了解決。

二、解決方法

本地第三方jar包引入方法：

<!--第三方jar包引入-->
<dependency>
    <groupId>com.hikvision.js</groupId>
    <artifactId>data-sdk-bms</artifactId>
    <version>2.0.3</version>
</dependency>

<plugin>
　　<groupId>org.apache.maven.plugins</groupId>
　　<artifactId>maven-install-plugin</artifactId>
　　<version>2.5.2</version>
　　<executions>
　　　　<execution>
　　　　　　<id>install-data-sdk-bms</id>
　　　　　　<phase>clean</phase>
　　　　　　<configuration>
　　　　　　　　<file>${project.basedir}/lib/data-sdk-bms-2.0.3.jar</file>
　　　　　　　　<repositoryLayout>default</repositoryLayout>
　　　　　　　　<groupId>com.hikvision.js</groupId>
　　　　　　　　<artifactId>data-sdk-bms</artifactId>
　　　　　　　　<version>2.0.3</version>
　　　　　　　　<packaging>jar</packaging>
　　　　　　　　<generatePom>true</generatePom>
　　　　　　</configuration>
　　　　<goals>
　　　　　　<goal>install-file</goal>
　　　　</goals>
　　　</execution>
　　</executions>
</plugin>

按上面的方式配置pom，打包正常，windows和linux環境下運行也正常。