为什么是 ！ 在docker上的spring-boot应用程序的属性文件路径中？

Question

I developed the rest API. So, I tried to run it on the docker. However, when I run it, it gives me file not found error.

This is file list in the app.jar.

This is error message.

Caused by: java.io.FileNotFoundException: file:app.jar!/BOOT-INF/classes!/application_variable.properties (No such file or directory)
        at java.io.FileInputStream.open0(Native Method) ~[na:1.8.0_111]
        at java.io.FileInputStream.open(FileInputStream.java:195) ~[na:1.8.0_111]
        at java.io.FileInputStream.<init>(FileInputStream.java:138) ~[na:1.8.0_111]
        at java.io.FileInputStream.<init>(FileInputStream.java:93) ~[na:1.8.0_111]
        at com.t3q.userManage.utils.SSOProperties.<init>(SSOProperties.java:31) ~[classes!/:0.0.1-SNAPSHOT]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_111]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_111]
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_111]
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:172) ~[spring-beans-5.1.6.RELEASE.jar!/:5.1.6.RELEASE]
        ... 53 common frames omitted

How can I solve this problem? ps. It works well in the eclipse!

ADDED. This is my Dockerfile.

FROM java:8
VOLUME /tmp
EXPOSE 8080
ADD target/userManageWithRest-0.0.1-SNAPSHOT.jar app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

This is SSOProperties.

public class SSOProperties {
    private static String servicePayloadDefault = "ID";
    private static final Logger logger = LoggerFactory.getLogger(SSOProperties.class);

    private String rootPath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
    private String propertiesPath = "application_variable.properties";
    private Properties props;


    public SSOProperties() throws FileNotFoundException, IOException {
        props = new Properties();
        rootPath = rootPath.replaceAll("%20", " ");
        rootPath = rootPath.replaceFirst("/", "");
        props.load(new FileInputStream(rootPath + propertiesPath));

        logger.info("rootPath="+rootPath);
    }
    ...
}

Answer 1

Caused by: java.io.FileNotFoundException: file:app.jar!/BOOT-INF/classes!/application_variable.properties (No such file or directory)

That is standard way of Java to convey classloading of resources from archives.
What is after the ! is inside the app.jar file.
Same thing for classes! but that is inside a directory in an archive (the jar).

Your problem is there :

private String rootPath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
//...
props.load(new FileInputStream(rootPath + propertiesPath));

You pass rootPath that is String path but that is included in a archive (the jar ), the FileInputStream cannot access to it.
What you need is getting the inputstream from the archive and to pass it to the Properties.load() method:

InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(propertiesPath);
props.load(is);

Note that as you use Spring you could also just do :

ClassPathResource resource = new ClassPathResource(propertiesPath);
props.load(resource.getInputStream());

And you could even automate the properties loading thanks to @PropertySource and @ConfigurationProperties :

@Configuration
@PropertySource("classpath:application_variable.properties")
@ConfigurationProperties
public class VariableProperties {

    private String foo;
    private String bar;

    // getters and setters
}

And inject it wherever you need it.