There is case that cannot scan classes using SpringBootVFS

[kazuki43zoo]

Overview

See mybatis/mybatis-3#1500.

Conditions that matches this issue

If following all conditions are matched, the SpringBootVFS cannot scan classes correctly.

• Run without executable jar(e.g. Maven/Gradle Plugin, IDE, etc...)
• Scanning target classes are stored in jar file under maven local repository (e.g. ${HOME}/.m2/repository)
• Specified scanning base package is matched with prefix of groupId

In this case, all conditions are matched as follow:

• Run without executable jar because it use spring-boot-devtools
• Scanning target classes are stored in $HOME/.m2/repository/com/bee/kuna/kuna-server-db/0.1.1-RELEASE/kuna-server-db-0.1.1-RELEASE.jar
• Specified scanning base package is com.bee
• GroupId of artifact that stared target classes is com.bee.kuna -> the groupId prefix is matched with scanning base package(com.bee)

Fix version

• 2.0.1
• 1.3.4 (backport) Fix resources scanning bug on SpringBootVFS #305

[kazuki43zoo]

The valid workaround is changing the scanning base package to more nested package(e.g. com.bee.kuna.typehandler).

NOET:
Does not support the wildcard as the scanning base package (e.g. com.bee.*.typehandler). If you need to scan classes from multiple package, please specify base package for each. (e.g. mybatis.type-handlers-package=com.bee.kuna.typehandler,com.bee.foo.typehandler)

[kazuki43zoo]

This issue's root cause are following code in SpringBootVFS.

spring-boot-starter/mybatis-spring-boot-autoconfigure/src/main/java/org/mybatis/spring/boot/autoconfigure/SpringBootVFS.java

Lines 57 to 65 in ba00741

	private static String preserveSubpackageName(final Resource resource, final String rootPath) {
	try {
	final String uriStr = resource.getURI().toString();
	final int start = uriStr.indexOf(rootPath);
	return uriStr.substring(start);
	} catch (IOException e) {
	throw new UncheckedIOException(e);
	}
	}

In this implementation, the MyBatis will try to scan the /com/bee/kuna/kuna-server-db/0.1.1-RELEASE/kuna-server-db-0.1.1-RELEASE.jar!com/bee/kuna/typehandler/FooTypeHandler.class.
In this case, the MyBatis should be scan com/bee/kuna/typehandler/FooTypeHandler.class.

I think uriStr.indexOf(rootPath); should be changed to uriStr.lastIndexOf(rootPath); .

New suggestion is as follow:

  @Override
  protected List<String> list(URL url, String path) throws IOException {
    String urlString = url.toString();
    String baseUrlString = urlString.endsWith("/") ? urlString : urlString.concat("/");
    Resource[] resources = resourceResolver.getResources(baseUrlString + "**/*.class");
    return Stream.of(resources)
        .map(resource -> preserveSubpackageName(baseUrlString, resource, path))
        .collect(Collectors.toList());
  }

  private static String preserveSubpackageName(final String baseUrlString, final Resource resource, final String rootPath) {
    try {
      return rootPath + (rootPath.endsWith("/") ? "" :  "/")
          + resource.getURL().toString().substring(baseUrlString.length());
    } catch (IOException e) {
      throw new UncheckedIOException(e);
    }
  }

Above solution work fine on following runtime env:

• IDE execution feature (Java application and XUnit)
• Spring Boot Maven Plugin (mvn spring-boot:run)
• Executable Jar file / War file (java -jar)
• Deploying War file on Tomcat

[kazuki43zoo]

@eddumelendez WDYT? Is correct my analysis and suggestion?

[kazuki43zoo]

@wamaco

Thanks for your report!
I propose to apply workaround until fix this issue. See #301 (comment).