小编典典

作为 jar 运行时找不到类路径资源

all

在 Spring Boot 1.1.5 和 1.1.6 中都有这个问题 - 我正在使用 @Value 注释加载一个类路径资源,当我从
STS(3.6.0,Windows)中运行应用程序时它工作得很好。但是,当我运行 mvn 包然后尝试运行 jar 时,我得到 FileNotFound
异常。

资源 message.txt 位于 src/main/resources 中。我检查了 jar 并验证它在顶层(与
application.properties 相同)包含文件“message.txt”。

这是应用程序:

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application implements CommandLineRunner {

    private static final Logger logger = Logger.getLogger(Application.class);

    @Value("${message.file}")
    private Resource messageResource;

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

    @Override
    public void run(String... arg0) throws Exception {
        // both of these work when running as Spring boot app from STS, but
        // fail after mvn package, and then running as java -jar
        testResource(new ClassPathResource("message.txt"));
        testResource(this.messageResource);
    }

    private void testResource(Resource resource) {
        try {
            resource.getFile();
            logger.debug("Found the resource " + resource.getFilename());
        } catch (IOException ex) {
            logger.error(ex.toString());
        }
    }
}

例外:

c:\Users\glyoder\Documents\workspace-sts-3.5.1.RELEASE\classpath-resource-proble
m\target>java -jar demo-0.0.1-SNAPSHOT.jar

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.1.5.RELEASE)

2014-09-16 08:46:34.635  INFO 5976 --- [           main] demo.Application
                  : Starting Application on 8W59XV1 with PID 5976 (C:\Users\glyo
der\Documents\workspace-sts-3.5.1.RELEASE\classpath-resource-problem\target\demo
-0.0.1-SNAPSHOT.jar started by glyoder in c:\Users\glyoder\Documents\workspace-s
ts-3.5.1.RELEASE\classpath-resource-problem\target)
2014-09-16 08:46:34.640 DEBUG 5976 --- [           main] demo.Application
                  : Running with Spring Boot v1.1.5.RELEASE, Spring v4.0.6.RELEA
SE
2014-09-16 08:46:34.681  INFO 5976 --- [           main] s.c.a.AnnotationConfigA
pplicationContext : Refreshing org.springframework.context.annotation.Annotation
ConfigApplicationContext@1c77b086: startup date [Tue Sep 16 08:46:34 EDT 2014];
root of context hierarchy
2014-09-16 08:46:35.196  INFO 5976 --- [           main] o.s.j.e.a.AnnotationMBe
anExporter        : Registering beans for JMX exposure on startup
2014-09-16 08:46:35.210 ERROR 5976 --- [           main] demo.Application
                  : java.io.FileNotFoundException: class path resource [message.
txt] cannot be resolved to absolute file path because it does not reside in the
file system: jar:file:/C:/Users/glyoder/Documents/workspace-sts-3.5.1.RELEASE/cl
asspath-resource-problem/target/demo-0.0.1-SNAPSHOT.jar!/message.txt
2014-09-16 08:46:35.211 ERROR 5976 --- [           main] demo.Application
                  : java.io.FileNotFoundException: class path resource [message.
txt] cannot be resolved to absolute file path because it does not reside in the
file system: jar:file:/C:/Users/glyoder/Documents/workspace-sts-3.5.1.RELEASE/cl
asspath-resource-problem/target/demo-0.0.1-SNAPSHOT.jar!/message.txt
2014-09-16 08:46:35.215  INFO 5976 --- [           main] demo.Application
                  : Started Application in 0.965 seconds (JVM running for 1.435)

2014-09-16 08:46:35.217  INFO 5976 --- [       Thread-2] s.c.a.AnnotationConfigA
pplicationContext : Closing org.springframework.context.annotation.AnnotationCon
figApplicationContext@1c77b086: startup date [Tue Sep 16 08:46:34 EDT 2014]; roo
t of context hierarchy
2014-09-16 08:46:35.218  INFO 5976 --- [       Thread-2] o.s.j.e.a.AnnotationMBe
anExporter        : Unregistering JMX-exposed beans on shutdown

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2022-08-16

共1个答案

小编典典

resource.getFile()期望资源本身在文件系统上可用,即它不能嵌套在
jar 文件中。这就是为什么当您在 STS(Spring Tool Suite)中运行您的应用程序时它可以工作,但一旦您构建了应用程序并从可执行 jar
运行它就不能工作。getFile()我建议使用而不是使用来访问资源的内容getInputStream()。这将允许您阅读资源的内容,无论它位于何处。

2022-08-16